One Nation. One Grid
REACTIVE POWER MANAGEMENT
&
VOLTAGE CONTROL
IN
NORTH EASTERN REGION
POWER SYSTEM OPERATION CORPORATION LIMITED
(A wholly owned subsidiary of Powergrid)
(A GOVT. OF INDIA UNDERTAKING)
NORTH EASTERN REGIONAL LOAD DESPATCH CENTRE
SHILLONG
Edition December 2014
Prepared by: System Operation - I department
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
CONTENTS
EXECUTIVE SUMMARY
5
1
6
6
8
10
11
12
13
14
17
20
Reactive Power Management and Voltage Control
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2
3
4
5
Transmission Lines and Reactive Power Compensation
21
2.1
2.2
2.3
2.4
21
23
23
24
Introduction
Surge impedance loading (SIL)
Shunt compensation in line
Line loading as function of line length and compensation
Series and Shunt Capacitor Voltage Control
40
3.1
3.2
3.3
40
41
41
Introduction
MeSEB capacity building and training document suggestion
THE ASSAM GAZETTE, EXTRAORDINARY, FEBRUARY 10, 2005
Transformer Load Tap Changer and Voltage Control
44
4.1
4.2
44
45
Introduction
THE ASSAM GAZETTE, EXTRAORDINARY, FEBRUARY 10, 2005
HVDC and Voltage Control
5.1
5.2
5.3
5.4
6
Introduction
Analogy of Reactive Power
Understanding Vectorially
Voltage Stability
Voltage Collapse
Proximity to Instability
Reactive reserve margin
NER GRID – OVERVIEW
Reliability improvement due to local voltage regulation
Introduction
HVDC Configuration
Reactive power source
”Inter-regional Transmission system for power export from
NER to NR/WR”
57
57
57
60
60
FACTS and Voltage Control
61
6.1
6.2
6.3
6.4
61
61
62
63
Introduction
Static Var Compensator (SVC)
Converter-based Compensator
Series-connected controllers
Page 1 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
7
Generator Reactive Power and Voltage Control
64
7.1
7.2
64
66
Introduction
Synchronous condensers
8
CONCLUSION
91
9
SUMMARY
89
10
Statutory Provisions for Reactive Power Management and
Voltage Control
94
10.1
94
10.2
10.3
11.
Provision in the Central Electricity Authority (Technical
Standard for connectivity to the grid) Regulations 2007 [8]:
Provision in the Indian Electricity Grid Code (IEGC), 2010
94
99
THE ASSAM GAZETTE, EXTRAORDINARY, FEBRUARY 10, 2005
Bibliography
103
Details of List
LIST-1:
LIST-2:
LIST-3:
LIST-4:
LIST-5:
LIST-6:
LIST-7:
LIST-8:
LIST-9:
LIST-10:
400 KV LINE DETAILS OF POWERGRID IN NORTH EASTERN REGION
400 KV LINE (CHARGED AT 220 KV) DETAILS OF POWERGRID IN NORTH
EASTERN REGION
220 KV LINE DETAILS OF POWERGRID IN NORTH EASTERN REGION
132 KV LINE DETAILS OF POWERGRID IN NORTH EASTERN REGION
132 KV LINE DETAILS OF NEEPCO IN NORTH EASTERN REGION
132 KV LINE DETAILS OF AEGCL IN NORTH EASTERN REGION
132 KV LINE DETAILS OF MANIPUR IN NORTH EAST
132 KV LINE DETAILS OF TSECL IN NORTH EASTERN REGION
132 KV LINE DETAILS OF NAGALAND IN NORTH EASTERN REGION
132 KV LINE DETAILS OF MIZORAM IN NORTH EASTERN REGION
LIST-11:
132 KV LINE DETAILS OF MeECL IN NORTH EAST
32
LIST-12:
LIST-13:
LIST-14:
LIST-15:
LIST-16:
LIST-17:
132 KV LINE DETAILS OF ARUNACHAL PRADESH IN NORTH EAST
66 KV LINE DETAILS OF NORTH EASTERN REGION
SHUNT COMPENSATED LINES IN NORTH EASTERN REGION
SHUNT COMPENSATED INTER – REGIONAL LINES IN NORTH EASTERN REGION
INTER-STATE LINE DETAILS OF NORTH EASTERN REGION
FIXED, SWITCHABLE AND CONVERTIBLE LINE REACTORS IN NORTH EASTERN
REGION
BUS REACTORS IN NORTH EASTERN REGION
TERTIARY REACTORS ON 33 KV SIDE OF 400/220/33 KV ICTS IN NORTH EASTERN
REGION
SUBSTATIONS IN NER
SHUNT CAPACITOR DETAILS OF NORTH EASTERN REGION
ICT DETAILS OF POWERGRID IN NORTH EASTERN REGION
ICT DETAILS OF NEEPCO IN NORTH EASTERN REGION
ICT DETAILS OF NHPC IN NORTH EASTERN REGION
32
33
34
35
35
LIST-18:
LIST-19:
LIST-20:
LIST-21:
LIST-22:
LIST-23:
LIST-24:
Page 2 of 103
26
26
27
27
28
29
29
31
31
32
36
37
39
39
42
46
46
47
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
LIST-25:
LIST-26:
LIST-27:
LIST-28:
LIST-29:
LIST-30:
LIST-31:
LIST-32:
LIST-33:
ICT DETAILS OF ARUNACHAL PRADESH IN NORTH EASTERN REGION
ICT DETAILS OF AEGCL IN NORTH EASTERN REGION
ICT DETAILS OF MANIPUR IN NORTH EASTERN REGION
ICT DETAILS OF MeECL IN NORTH EASTERN REGION
ICT DETAILS OF MIZORAM IN NORTH EASTERN REGION
ICT DETAILS OF NAGALAND IN NORTH EASTERN REGION
ICT DETAILS OF TSECL IN NORTH EASTERN REGION
ICT DETAILS OF OTPC IN NORTH EASTERN REGION
TRANSMISSION/TRANSFORMATION/VAR COMPENSATION CAPACITY OF NER
47
47
52
52
53
54
55
56
56
List of Figures
Fig1.
Fig2.
Fig3.
Fig4.
Fig5.
Fig6.
Fig7.
Fig8.
Fig9.
Fig10.
Fig11.
Fig12.
Fig13.
Fig14.
Fig15.
Fig16.
Fig17.
Fig18.
Voltage and Current waveforms
Power Triangle
Boat pulled by a Horse
Direction of pull
Vector representation of the analogy
LABYRINTSPEL
Vector representation
Time frames for voltage stability phenomena
PV curve and voltage stability margin under different conditions
Average cost of reactive power technologies
NER grid map
SIL vs. Compensation
Switching principles of LTC
HVDC fundamental components
Static VAR Compensators (SVC)
STATCOM topologies
Series-connected FACTS controllers
D-Curve of a typical Generator
6
7
8
8
8
9
10
13
14
16
17
24
44
59
62
62
63
64
Annexure: Capability Curve of generating machines of NER
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
LTPS UNIT 5, 6 & 7 CAPABILITY CURVE
NTPS UNIT 1, 2 & 3 CAPABILITY CURVE
NTPS UNIT 4 CAPABILITY CURVE
NTPS UNIT 6 CAPABILITY CURVE
LTPS CAPABILITY CURVE
NTPS CAPABILITY CURVE
UMIUM ST I CAPABILITY CURVE
UMIUM STAGE II CAPABILITY CURVE
UMIUM STAGE III CAPABILITY CURVE
UMIUM STAGE IV CAPABILITY CURVE
AGBPP UNIT 5, 6, 7, 8 & 9 CAPABILITY CURVE
AGBPP UNIT 1, 2, 3 & 4 CAPABILITY CURVE
AGTPP CAPABILITY CURVE
DOYANG HEP UNIT 1 CAPABILITY CURVE
KHANDONG HEP UNIT 2 CAPABILITY CURVE
KOPILI HEP UNIT 1 CAPABILITY CURVE
KOPILI HEP UNIT 2 CAPABILITY CURVE
KOPILI HEP ST II CAPABILITY CURVE
RANGANADI HEP CAPABILITY CURVE
Page 3 of 103
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
20
21
22
23
24
LOKTAK HEP CAPABILITY CURVE
ROKHIA UNIT 3, 4 & 6 CAPABILITY CURVE
ROKHIA & BARAMURA CAPABILITY CURVE
OTPC PALATANA GTG CAPABILITY CURVE
OTPC PALATANA STG CAPABILITY CURVE
86
87
88
89
90
List of Tables
Table 1
Table 2
Table 3
Table 4
Table 5
Table 6
Reactive power compensation sources
Fault level at important sub-stations of NER
Line Parameters and Surge Impedance Loading of Different Conductor Type
Equipment preference
List of units in NER to be normally operated with free governor
action and AVR in service
IEGC Operating Voltage Range
Page 4 of 103
16
19
25
40
66
97
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
EXECUTIVE SUMMARY
Quality
of power to the stakeholders is the question of the hour worldwide.
Enactment of several regulations viz. IE act – 2003, ABT, Open access regulations,
IEGC, DSM and
several other amendments are in the direction towards
improvement of system reliability and power quality.
It is also significant to mention that due to the massive load growth in the country,
the existing power networks are operated under greater stress with transmission
lines carrying power near their limits. Increase in the complexity of network and
being loaded non-uniformly has increased its vulnerability to grid disturbances due
to abnormal voltages (High and Low). In the past, reason for many a black outs
across the world have been attributed to this cause.
Three
objectives dominate reactive power management. Firstly, maintaining
adequate voltage throughout the transmission system under normal and
contingency conditions. Secondly, minimizing congestion of real – power flows.
Thirdly, minimizing real – power losses. Also with dynamic ATCs, var
compensation, congestion charges, if not seriously thought, it may have serious
commercial implications in times to come due to the amount of bulk power transfer
across the country.
Highlights of the rolling year vis-à-vis NER grid includes commissioning of 400 kV
Azara – Silchar S/C, 400/220 kV 315 MVA ICT I & II at Azara, 400 kV Balipara –
Bongaigaon III & IV with convertible line reactors at both the ends, 400 kV
Bongaigaon – Siliguri III & IV inter-regional lines have led to reinforcement in the
NER grid elements and greater options of controlling grid parameters. With the
increase in controllability compared to earlier years, grid operation has been
smooth and grid parameters were maintained within the prescribed IEGC limits.
This manual is in continuation to the previous edition to understand the basics of
reactive power and its management towards voltage control, its significance and
consequences of inadequate reactive power support. It also includes details of
reactive power support available at present and efforts by planners from future
perspective in respect of NER grid.
Page 5 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
1
1.1
Reactive Power Management and Voltage
Control
Introduction
1.1.1
W
1.1.2
Power flows, both actual and potential, must be carefully controlled for a
power system to operate within acceptable voltage limits. Reactive power
flows can give rise to substantial voltage changes across the system,
which means that it is necessary to maintain reactive power balances
between sources of generation and points of demand on a 'zonal basis'.
Unlike system frequency, which is consistent throughout an
interconnected system, voltages experienced at points across the system
form a "voltage profile" which is uniquely related to local generation and
demand at that instant, and is also affected by the prevailing system
network arrangements.
1.1.3
In an interconnected AC grid,
the voltages and currents
alternate up and down 50
times
per
second
(not
necessarily at the same time).
In that sense, these are
pulsating quantities. Because
of this, the power being
transmitted down a single line
also “pulsates” - although it
goes up and down 100 times
per second rather than 50.
hat is Reactive Power ? Reactive power is a concept used by
engineers to
describe
the background energy movement in
an Alternating Current (AC) system arising from the production of
electric and magnetic fields. These fields store energy which changes
through each AC cycle. Devices which store energy by virtue of a
magnetic field produced by a flow of current are said to absorb reactive
power (viz. transformers, Reactors) and those which store energy by
virtue of electric fields are said to generate reactive power (viz.
Capacitors).
Page 6 of 103
Fig 1. Voltage and Current waveforms
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
1.1.4
To distinguish reactive power from real power, we use the reactive power
unit called “VAR” - which stands for Volt-Ampere-Reactive (Q). Normally
electric power is generated, transported and consumed in alternating
current (AC) networks. Elements of AC systems supply (or produce) and
consume (or absorb or lose) two kinds of power: real power and reactive
power.
1.1.5
Real power accomplishes useful work (e.g., runs motors and lights
lamps). Reactive power supports the voltages that must be controlled for
system reliability. In AC power networks, while active power corresponds
to useful work, reactive power supports voltage magnitudes that are
controlled for system reliability, voltage stability, and operational
acceptability.
1.1.6
VAR Management? It is defined as the control of generator voltages,
variable transformer tap settings, compensation, switchable shunt
capacitor and reactor banks plus allocation of new shunt capacitor and
reactor banks in a manner that best achieves a reduction in system
losses and/or voltage control.
1.1.7
Although active power can be transported over long distances, reactive
power is difficult to transmit, since the reactance of transmission lines is
often 4 to 10 times higher than the resistance of the lines. When the
transmission system is heavily loaded, the active power losses in the
transmission system are also high. Reactive power (vars) is required to
maintain the voltage to deliver active power (watts) through transmission
lines. When there is not enough reactive power, the voltage sags down
and it is not possible to push the power demanded by loads through the
lines. Reactive power supply is necessary in the reliable operation of AC
power systems. Several recent power outages worldwide may have been
a result of an inadequate reactive power supply which subsequently led
to voltage collapse.
1.1.8
Voltage and current may not pulsate up and
down at the same time. When the voltage and
current do go up and down at the same time,
only real power is transmitted. When the
voltage and current go up and down at
different times, reactive power is also gets
transmitted. How much reactive power and
which direction it is flowing on a transmission
line depend on how different these two items
are.
Page 7 of 103
Fig 2. Power Triangle
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
Although AC voltage and current pulsate at the same frequency, they
peak at a different time. Power is the algebraic product of voltage and
current. Over a cycle, power has an average value, called real power (P),
measured in volt-amperes, or watts. There is also a portion of power with
zero average value that is called reactive power (Q), measured in voltamperes reactive, or vars. The total power is called apparent power or
Complex power, measured in volt-amperes, or VA.
1.2
Analogy of Reactive Power
1.2.1
Why an analogy? Reactive Power is an essential aspect of the electricity
system, but one that is difficult to comprehend by a lay man. The horse
and the boat analogy best describe the Reactive Power aspect.
Visualize a boat on a canal, pulled by a horse on the bank of the canal.
Fig 3. Boat pulled by a Horse
Fig 4. Direction of pull
In actual the horse is not in front of the boat to do a meaningful work of
pulling it in a straight path. Due to the balancing compensation by the
rudder of the boat, the boat is made to move in a straight manner rather
deviating towards the bank. This is in line with the understanding of the
reactive power.
Fig 5. Vector representation of the analogy
Page 8 of 103
W
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
1.2.1
In the horse and boat analogy, the horse’s objective (real power) is to
move the boat straightly. The fact that the rope is being pulled from the
flank of the horse and not straight behind it, limits the horse’s capacity to
deliver real work of moving straightly. Therefore, the power required to
keep the boat steady in navigating straightly is delivered by the rudder
movement (reactive power). Without reactive power there can be no
transfer of real power, likewise without the support of rudder, the boat
cannot move in a straight line.
1.2.2
Reactive power is like the bouncing up and down that happens when we
walk on a trampoline. Because of the nature of the trampoline, that updown bouncing is an essential part of our forward movement across the
trampoline, even though it appears to be movement in the opposite
direction.
1.2.3
Reactive power and real power work together in the way that’s illustrated
very well by the labyrinth puzzle, LABYRINTSPEL:
The description of the puzzle begins to
show why this game represents the
relationship between real and reactive
power:
The intent is to manipulate a steel ball
(1.2cm in diameter) through the maze by
rotating the knobs – without letting the ball
fall into one of the holes before it reaches
the end of the maze. If a ball does fall
prematurely into a hole, a slanted floor
inside the box returns the ball to the user in
the trough on the lower right corner of the
box.
Fig 6. LABYRINTSPEL
1.2.4
The Objective is to twist the two knobs to adjust the angle of the platform
in two directions, in order to keep the ball rolling through the maze
without falling into any holes. Those twists are REACTIVE POWER, which
helps propel the real power through to its ultimate goal, which is delivery
to the user. Without reactive power, ball falls into holes along the way,
which are NETWORK failures.
1.2.5
Both of these examples illustrate how important it is to understand the
system and how it works in order to meet our objectives effectively. In the
LABYRINTSPEL game, if the structure of the system is not taken into
account, winning would be really easy because one knob would be turned
Page 9 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
all the way in one direction, and the other knob all the way in the other
direction, and the ball would merely roll across the platform. If that’s the
model how electricity works, then that would deliver the electrons to the
end user in the form of real power. But in the game, on the trampoline,
and in the electric power network, the system has more going on that
means it’s essential to do things that seem counterintuitive, like bouncing
up and down on the trampoline or turning the platform in the game
towards west to avoid the hole to the east, even though we have to go
east to win.
1.2.6
In electric power, the counterintuitive thing about reactive power is to use
some power along the path to balance the flow of electrons and the
circuits. Otherwise, the electricity just flows from the generator to the
largest consumer (that’s Kirchhoff’s law, basically). In this sense, reactive
power is like water pressure in a water network.
1.2.7
LABYRINTSPEL game and the trampoline are good examples that they
capture the fact that mathematically, real power and reactive power are
pure conjugates.
1.3
Understanding Vectorially
1.3.1
In practice circuits are invariably combinations of resistance, inductance
and capacitance. The combined effect of these impedances to the flow of
current is most easily assessed by expressing the power flows as vectors
that show the angular relationship between the powers waveforms
associated with each type of impedance. Figure 7 shows how the vectors
can be resolved to determine the net capacity of the circuit needed to
transfer the power requirements of the connected equipment.
1.3.2
The useful power that can be drawn
from the electricity distribution
system is represented by the vertical
vector in the diagram and is
measured in kilowatts (kW).The
reactive or wattless power that is a
consequence of the inductive load in
the circuit is represented by the
horizontal vector to the right and the
reactive power attributable to the
circuit capacitance by the horizontal
vector to the left. These are
measured in kilovars (kVAr).
Page 10 of 103
Fig 7. Vector representation
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
1.3.3
The resolution of these vectors, which is the diagonal vector in the
diagram is the capacity required to transmit the active power, and is
measured in kilovolts-ampere (kVA). The ratio of the kW to kVA is the
cosine of the angle in the diagram shown as theta, and is referred to as
the “power factor”.
1.3.4
When the net impedance of the circuit is solely resistance, so that the
inductance and capacitance exactly cancel each other out, then the angle
theta becomes zero and the circuit has a power factor of unity. The circuit
is now operating at its highest efficiency for transferring useful power.
However, as a net reactive power emerges the angle theta starts to
increase and its cosine falls.
1.3.5
At low power factors the magnitude of the kVA vector is significantly
greater than the real power or kW vector. Since distribution assets such
as cables, lines and transformers must be sized to meet the kVA
requirement, but the useful power drawn by the customer is the kW
component, a significant cost emerges from having to over-size the
distribution system to accommodate the substantial amount of reactive
power that is associated with the active power flow.
1.4
Voltage Stability
1.4.1
Power flows, both actual and potential, must be carefully controlled for a
power system to operate within acceptable voltage limits and vice versa.
Not only is reactive power necessary to operate the transmission system
reliably, but it can also substantially improve the efficiency with which
real power is delivered to customers. Increasing reactive power
production at certain locations (usually near a load center) can
sometimes alleviate transmission constraints and allow cheaper real
power to be delivered into a load pocket.
1.4.2
Voltage control (keeping voltage within defined limits) in an electric
power system is Important for proper operation of electric power
equipment and saving it from imminent damage, to reduce transmission
losses and to maintain the ability of the system to withstand disturbances
and prevent voltage collapse. In general terms, decreasing reactive power
causes voltages to fall, while increasing reactive power causes voltages
to rise. A voltage collapse occurs when the system is trying to serve
much more load than the voltage can support.
1.4.3
As voltage drops, current must increase to maintain the power supplied,
causing the lines to consume more reactive power and the voltage to
drop further. If current increases too much, transmission lines trip, or go
off-line, overloading other lines and potentially causing cascading
Page 11 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
failures. If voltage drops too low, some generators will automatically
disconnect to protect themselves.
1.4.4
Usually the causes of under – voltages are:
•
Overloading of supply transformers
•
Inadequate short circuit level in the point of supply
•
Excessive voltage drop across a long feeder
•
Poor power factor of the connected load
•
Remote system faults , while they are being cleared
•
Interval in re-closing of an auto-reclosure
•
Starting of large HP induction motors
1.4.5
If the declines continue, these voltage reductions cause additional
elements to trip, leading to further reduction in voltage and loss of load.
The result is a progressive and uncontrollable decline in voltage, all
because the power system is unable to provide the reactive power
required to supply the reactive power demand.
1.5
Voltage Collapse
1.5.1
When voltages in an area are significantly low or blackout occurs due to
the cascading events accompanying voltage instability, the problem is
considered to be a voltage collapse phenomenon. Voltage collapse
normally takes place when a power system is heavily loaded and/or has
limited reactive power to support the load. The limiting factor could be the
lack of reactive power (SVC and generators hit limits) production or the
inability to transmit reactive power through the transmission lines.
1.5.2
The main limitation in the transmission lines is the loss of large amounts
of reactive power and also line outages, which limit the transfer capacity
of reactive power through the system.
1.5.3
In the early stages of analysis, voltage collapse was viewed as a static
problem but it is now considered to be a non linear dynamic
phenomenon. The dynamics in power systems involve the loads, and
voltage stability is directly related to the loads. Hence, voltage stability is
also referred to as load stability.
1.5.4
There are other factors which also contribute to voltage collapse, and
are as below:
•
•
•
Increase in load
Action of tap changing transformers
Load recovery dynamics
Page 12 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
All these factors play a significant part in voltage collapse as they effect
the transmission, consumption, and generation of reactive power.
Usually voltage stability is categorized into two parts
•
•
Large disturbance voltage stability
Small disturbance voltage stability
Fig 8. Time frames for voltage stability phenomena
1.5.5
When a large disturbance occurs, the ability of the system to maintain
acceptable voltages falls due to the impact of the disturbance. Ability to
maintain voltages is dependent on the system and load characteristics,
and the interactions of both the continuous and the discrete controls and
protections. Similarly, the ability of the system to maintain voltages after
a small perturbation i.e. incremental change in load is referred to as small
disturbance voltage stability. It is influenced by the load characteristics,
continuous control and discrete controls at a given instant of time.
1.6
Proximity to Instability
1.6.1
Static voltage instability is mainly associated with reactive power
imbalance. Thus, the loadability of a bus in a system depends on the
reactive power support that the bus can receive from the system. As the
system approaches the maximum loading point or voltage collapse point,
both real and reactive power losses increase rapidly.
Page 13 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
1.6.2
Therefore, the reactive power supports have to be locally adequate. With
static voltage stability, slowly developing changes in the power system
occur that eventually lead to a shortage of reactive power and declining
voltage.
1.6.3
This phenomenon can be seen from
a plot of power transferred versus
voltage at the receiving end. These
plots are popularly referred to as
P–V curves or ‘Nose’ curves. As
power transfer increases, the
voltage at the receiving end
decreases. In the fig(9) eventually, a
critical (nose) point, the point at
which the system reactive power is
out of usage, is reached where any
further increase in active power
transfer will lead to very rapid
decrease in voltage magnitude.
Knee
point
∆v
Fig 9. PV curve and Voltage stability margin
under different conditions
1.6.4
Before reaching the critical point, a large voltage drop due to heavy
reactive power losses is observed. The only way to save the system from
voltage collapse is to reduce the reactive power load or add additional
reactive power prior to reaching the point of voltage collapse.
•
•
•
•
These are curves drawn between V and P of a critical bus at a
constant load power factor.
These are produced by using a series of power flow
solutions for different load levels.
At the knee point or the nose point of the V-P curve, the
voltage drops rapidly with an increase in the load demand.
Power flow solution fails to converge beyond this limit which
indicates the instability.
1.7
Reactive Reserve Margin
1.7.1
The amount of unused available capability of reactive power static as well
as dynamic in the system (at peak load for a utility system) as a
percentage of total capability is known as Reactive reserve margin.
1.7.2
Voltage collapse normally occurs when sources producing reactive
power reach their limits i.e. generators, SVCs or shunt reactors, and there
is not much reactive power to support the load. As reactive power is
Page 14 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
directly related to voltage collapse, it can be used as a measure of voltage
stability margin.
1.7.3
The voltage stability margin can be defined as a measure of how close the
system is to voltage instability, and by monitoring the reactive reserves in
the power system, proximity to voltage collapse can be monitored.
1.7.4
In case of reactive reserve criteria, the reactive power reserve of an
individual or group of VAr sources must be greater than some specified
percentage (x %) of their reactive power output under all contingencies.
The precincts where reactive power reserves were exhausted would be
identified as critical areas.
1.7.5
Reactive power requirements over and above those which occur naturally
are provided by an appropriate combination of reactive source/devices
which are normally classified as static and dynamic devices.
1.7.6
•
STATIC SOURCES: Static sources are typically transmission
and distribution equipments such as Capacitors and
Reactors that are relatively static and can respond to the
changes in voltage – support requirements only slowly and
in discrete steps. Devices are inexpensive, but the
associated switches, control, and communications, and their
maintenance, can amount to as much as one third of the total
operations and maintenance budget of a distribution system.
•
DYNAMIC SOURCES: It includes pure reactive power
compensators like synchronous condensers, Synchronous
generators and solid-state devices such as FACTS, SVC,
STATCOM, D-VAR, and SuperVAR which are normally
dynamic and can respond within cycles to changing reactive
power requirement. These are typically considered as
transmission service devices.
Static devices typically have lower capital costs than dynamic devices,
and from a system point of view, they are used to provide normal or
intact-system voltage support and to adapt to slowly changing
conditions, such as daily load cycles and scheduled transactions. By
contrast, dynamic reactive power sources must be deployed to allow the
transmission system to respond to rapidly changing conditions on the
transmission system, such as sudden loss of generators or transmission
facilities. An appropriate combination of both static and dynamic
resources is needed to ensure reliable operation of the transmission
system at an appropriate level of costs.
Page 15 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
1.7.7
Reactive power absorption occurs when current flows through an
inductance. Inductance is found in transmission lines, transformers, and
induction motors etc. The reactive power absorbed by a transmission line
or transformer is proportional to the square of the current.
Sources of Reactive Power
Static:
Shunt Capacitors
Filter banks
Under ground cables
Transmission lines (lightly
loaded)
Fuel cells
PV systems
Dynamic:
Synchronous Generators
Synchronous Condensers
FACTS (e.g.,SVC,STATCOM)
Sinks of Reactive Power
Transmission lines (Heavily
loaded)
Transformers
Shunt Reactors
Synchronous machines
FACTS (e.g.,SVC,STATCOM)
Induction generators (wind
plants)
Loads
• Induction motors (Pumps,
Fans etc)
• Inductive loads (Arc furnace
etc)
Table 1. Reactive power compensation sources
1.7.8
A transmission line also has capacitance. When a small amount of
current is flowing, the capacitance dominates, and the lines have a net
capacitive effect which raises voltage. This happens at night when
current flows/Load is low. During the day, when current flow/load is high,
inductive effect is greater than the capacitance, and the voltage sags.
Fig 10. Average cost of Reactive power technologies
Page 16 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
1.8
NER GRID – Overview
1.8.1
NER grid with a maximum peak requirement of around 2100 MW and
installed capacity of 2746 MW caters to the seven north eastern states. It
is synchronously connected with NEW GRID through 400 kV QUAD/C
BONGAIGAON – NEW SILIGURI, 220 kV D/C BIRPARA – SALAKATI and
internationally through 132 kV SALAKATI – GELYPHU(Bhutan) and 132 kV
Rangia - Deothang. The bottle neck of operating the NER grid arises
because of the brittle back bone network of about 7666 Ckt Kms of 132
KV lines, 2084 Ckt Kms of 400 KV lines and 2925 Ckt Kms of 220 KV lines
compared to other regional grids.
Fig 11. NER Grid map
1.8.2
Almost 50% of the total NER load is spread out in 132 kV pocket of
southern part of NER which were without the direct support of major EHV
trunk lines. This part of the network was highly sensitive and was
susceptible to grid disturbance in the past and demanded more
operational acumen. Increase in the loading of major 132 kV trunk lines,
in particular 132 kV DIMAPUR – IMPHAL S/C,132 kV JIRIBAM – LOKTAK
S/C and 132 kV BADARPUR – KHLIEHRIAT S/C in peak hours has led to
Page 17 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
many a grid incidents in the past in the form of cascade tripping
accompanied by voltage sag. However, with system augmentation grid
incidence in this part of the grid has become a matter of past.
1.8.3
NER system has been strengthened with the commissioning of 400 kV
AZARA – Silchar S/C, 400/220 kV 315 MVA ICT I & II, 400 kV Balipara –
Bongaigaon III & IV, 400 kV Bongaigaon – Siliguri III & IV. With the
availability of greater options, grid operation has been smooth and grid
parameters were maintained within the prescribe IEGC limits.
1.8.4
Relationship between frequency and voltage is a well known fact. Studies
have revealed that though voltage is a localized factor, it is directly
affected by the frequency which is a notional factor. Any lopsidedness in
the demand/generation side leading to fluctuations in NEW grid frequency
affects NER grid immensely, in particular the voltage profile of the grid,
leading to sagging and swelling of voltage heavily during such occasions.
Ironically, NER was synchronously connected with NEW grid for
stretching the transmission capability to reduce the load – generation
mismatch of the country.
1.8.5
FSC’s have been integrated with the NER system in the 400 kV Balipara –
Bongaigaon III & IV at Balipara end . It is needed to be seen how far the
+/-800 KV HVDC project in NER which is in the execution stage will help in
maintaining a healthy voltage profile in the region with its reactive reserve
support in the form of filters and capacitor banks.
1.8.6
Presently NER Grid is supported by 2383 MVAr from shunt reactors and
273 MVAr from shunt capacitors spread across the region.
1.8.7
Skewness in the location of hydro stations and load centers in NER is
another obstacle which aggravates the voltage problem further. Lines are
long and pass through difficult terrains to the load centers. Northern part
of NER grid which is well supported by some strong 400 KV and 220 KV
network faces high voltage regime during lean hydro period as the
corridor is not fully utilized and is usually lightly loaded. Supports from
hydro stations in condenser mode are not available for containing low
voltage conditions. D curve optimization is yet to be realized fully due to
technical glitches.
1.8.8
Reactive power management and voltage control are two aspects of a
single activity that both supports reliability and facilitates commercial
transaction across transmission network. Controlling reactive power flow
can reduce losses and congestion on the transmission system.
Page 18 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
1.8.9
Operationally in NER, Voltage is normally controlled by managing
production and absorption of reactive power in real time :
•
•
Switching in and out of Line reactance compensators such
as capacitors and shunt reactors (Line/Bus Reactors) as and
when system demands in co-operation with the constituents
and the CTU.
Circuit switching: Mostly one circuit of the lightly loaded d/c
line is kept open keeping in mind the n-1 criterion during
high voltage and high frequency period. Voltage differences
as well as fault level of stations are taken into account before
any switching operation of circuits.
Fault levels of major substation in NER are as below:
Three Phase Fault Level (Minimum Fault Level with IEC) of Major Sub-Stations of NER
Off Peak
Bus
3 ϕ Fault
Current in kA
Peak
3 ϕ Fault MVA
3 ϕ Fault
Current in kA
3 ϕ Fault MVA
400 kV Substations
Azara (Mirza)
Balipara
Bongaigaon
Byrnihat
Misa
Palatana
Ranganadi
Silchar
3.2
5.9
8.2
3.5
5.6
4.3
3.8
4.8
2238
3.2
4093
6.0
5716
8.1
2403
3.4
3851
5.6
2977
4.3
2637
4.0
3222
4.6
220 kV Substations
2217
4178
5606
2384
3902
2966
2757
3189
AGBPP
(Kathalguri)
Agia
Azara (Mirza)
Balipara
Boko
BTPS
Byrnihat
Dimapur (PG)
Kopili
5.6
6.6
6.3
6.3
4.8
9.3
6.7
4.5
8.5
2132
2497
2383
2397
1841
3543
2566
1716
3252
2103
2418
2355
2426
1818
3306
2540
1738
3238
Page 19 of 103
5.5
6.3
6.2
6.4
4.8
8.7
6.7
4.6
8.5
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
Langpi
Mariani (AS)
Mariani (PG)
Misa
NTPS
Salakati
Samaguri
Sarusajai
Tinsukia
3.8
5.1
3.1
11.9
4.2
9.5
9.5
5.8
5.0
1438
3.8
1931
5.0
1193
3.1
4537
11.9
1601
4.1
3630
8.9
3629
9.6
2207
5.8
1920
4.9
132 kV Substations
1437
1902
1189
4554
1573
3377
3643
2201
1888
Silchar
Badarpur
Khandong
Khlierihat
AGTPP (RC
Nagar)
Kumarghat
Dimapur (PG)
Jiribam
Nirjuli
Loktak
Haflong
Doyang
Balipara
Aizawl
10.1
9.3
8.2
7.8
2315
2134
1864
1792
9.9
9.1
7.7
6.9
2273
2080
1772
1576
7.5
5.7
5.6
4.4
4.4
3.2
3.2
3.2
3.1
2.8
1716
1303
1273
1006
1000
732
734
738
720
646
7.5
5.7
5.7
4.5
4.6
3.7
3.2
3.3
3.2
2.8
1723
1306
1306
1032
1047
847
730
748
735
652
Table 2. Fault level at important Sub-Stations of NER
•
•
•
•
The generating units provide the basic means of voltage
control: The automatic voltage regulators (AVR) control field
excitation to maintain the scheduled voltage levels at the
terminals of the generators. In real time operation, connected
generation should never be on reactive generation or
absorption limits.
By generation re-dispatch/rescheduling.
Regulating voltage with the help of OLTC’s.
By load staggering/shedding.
Page 20 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
1.9
Reliability Improvement Due to Local Voltage Regulation
1.9.1
Local voltage regulation to a voltage schedule supplied by the utility can
have a very beneficial effect on overall system reliability, reducing the
problems caused by voltage dips on distribution circuits such as
dimming lights, slowing or stalling motors, dropout of contactors and
solenoids, and shrinking television pictures.
1.9.2
In past years a voltage drop would inherently reduce load, helping the
situation. Light bulbs would dim and motors would slow down with
decreasing voltage. Dimmer lights and slower motors typically draw less
power, so the situation was in a certain sense self-correcting. With
modern loads, this situation is changing.
1.9.3
Today many incandescent bulbs are being replaced with compact
fluorescent lights, LED lamps that draw constant power as voltage
decreases, and motors are being powered with adjustable-speed drives
that maintain a constant speed as voltage decreases. In addition, voltage
control standards are rather unspecific, and there is a tremendous
opportunity for an improvement in efficiency and reliability from better
voltage regulation. Capacitors supply reactive power to boost voltage, but
their effect is dramatically diminished as voltage dips.
1.9.4
Capacitor effectiveness is proportional to the square of the voltage, so at
80% voltage, capacitors are only 64% as effective as they are at normal
conditions. As voltage continues to drop, the capacitor effect falls off
until voltage collapses. The reactive power supplied by an inverter is
dynamic, it can be controlled very rapidly, and it does not drop off with a
decrease in voltage. Distribution systems that allow customers to supply
dynamic reactive power to regulate voltage could be a tremendous asset
to system reliability and efficiency by expanding the margin to voltage
collapse.
Page 21 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
2
2.1
TRANSMISSION LINES AND REACTIVE
POWER COMPENSATION
Introduction
2.1.1
In moving power from generators to loads, the transmission network
introduces both real and reactive losses. Housekeeping loads at
substations (such as security lighting and space conditioning) and
transformer excitation losses are roughly constant (i.e., independent of
the power flows on the transmission system). Transmission-line losses,
on the other hand, depend strongly on the amount of power being
transmitted.
2.1.2
Real-power losses arise because aluminum and copper (the materials
most often used for transmission lines) are not perfect conductors; they
have resistance. The consumption of reactive power by transmission
lines increases with the square of current i.e., the transmission of reactive
power requires an additional demand for reactive power in the system
components.
2.1.3
The reactive-power nature of transmission lines is associated with the
geometry of the conductors themselves (primarily the radius of the
conductor) and the geometry of the conductor configuration (the
distances between each conductor and ground and the distances among
conductors).
2.1.4
The reactive-power behavior of transmission lines is complicated by their
inductive and capacitive characteristics. At low line loadings, the
capacitive effect dominates, and generators and transmission-related
reactive equipment must absorb reactive power to maintain line voltages
within their appropriate limits. On the other hand, at high line loadings,
the inductive effect dominates, and generators, capacitors, and other
reactive devices must produce reactive power
2.1.5
The thermal limit is the loading point (in MVA) above which real power
losses in the equipment will overheat and damage the equipment. Most
transmission elements (e.g., conductors and transformers) have normal
thermal limits below which the equipment can operate indefinitely without
any damage. These types of equipment also have one or more emergency
limits to which the equipment can be loaded for several hours with
minimal reduction in the life of the equipment.
Page 22 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
2.1.6
2.2
If uncompensated, these line losses reduce the amount of real power that
can be transmitted from generators to loads. Transmission-line capacity
decreases as the line length increases if there is no voltage support
(injection or absorption of reactive power) on the line. At short distances,
the line’s capacity is limited by thermal considerations; at intermediate
distances the limits are related to voltage drop; and beyond roughly 300
to 350 miles, stability limits dominate.
Surge Impedance Loading (SIL)
2.2.1
Transmission lines and cables generate and consume reactive power at
the same time. The reactive power generation is almost constant,
because the voltage of the line is usually constant, and the line’s reactive
power consumption depends on the current or load connected to the line
that is variable. So at the heavy load conditions transmission lines
consume reactive power, decreasing the line voltage, and in the low load
conditions – generate, increasing line voltage.
2.2.2
The case when line’s reactive power produced by the line capacitance is
equal to the reactive power consumed by the line inductance is called
natural loading or surge impedance loading (SIL) , meaning that the line
provides exactly the amount of MVAr needed to support its voltage. The
balance point at which the inductive and capacitive effects cancel each
other is typically about 40% of the line’s thermal capacity. Lines loaded
above SIL consume reactive power, while lines loaded below SIL supply
reactive power.
2.2.3
A 400 kV, line generates approximately 55 MVAR per 100 km/Ckt, when it
is idle charged due to line charging susceptance. This implies a 300 km
line generates about 165 MVAR when it is idle charged.
2.3
Shunt Compensation in Line
2.3.1
Normally there are two types of shunt reactors – Line reactor and bus
reactor. Line reactor’s functionality is to avoid the switching and load
rejection over voltages where as Bus reactors are used to avoid the
steady state over voltage during light load conditions.
2.3.2
The degree of compensation is decided by an economic point of view
between the capitalized cost of compensator and the capitalized cost of
reactive power from supply system over a period of time. In practice a
compensator such as a bank of capacitors (or inductors) can be divided
into parallel sections, each Switched separately, so that discrete changes
Page 23 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
in the compensating reactive power may be made, according to the
requirements of the load.
2.3.3
Reasons for the application of shunt capacitor units are :
•
•
•
•
•
•
2.4
2.4.1
Increase voltage level at the load
Improves voltage regulation if the capacitor units are
properly switched.
Reduces I2R power loss in the system because of reduction
in current.
Increases power factor of the source generator.
Decrease kVA loading on the source generators and circuits
to relieve an overloaded condition or release capacity for
additional load growth.
By reducing kVA loading on the source generators additional
kilowatt loading may be placed on the generation if turbine
capacity is available.
Line loading as function of Line Length and Compensation
The operating
limits
for
transmission
lines
may be taken as
minimum
of
thermal
rating
of
conductors
and
the
maximum
permissible
line
loadings
derived
from
St.
Clair’s
curve.
SIL given
in
table
above
is
for
uncompensated line. If
k
is the compensation
then:
• For
a
shunt
compensated line:
SIL modified =SIL x √ (1-k)
•
For
a
series
compensated line:
SIL modified=SIL/ √ (1- k)
Fig 12. SIL VS Compensation
Further to take into account the line length one needs to multiple
the
modified SIL with the multiplying factor
derived from St. Clair's
curve.The derived steady state limit for a line would be = SIL modified x
factor from St. Clair's curve.
Page 24 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
Page 25 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
LIST-1: 400 KV LINE DETAILS OF NORTH EASTERN REGION
SR.
NO.
FROM
TO
UTILITY
KM
CKT
NETCL
264
1
CONDUCTOR
ACSR TWIN
MOOSE
ACSR
MOOSE/AACSR
ACSR
MOOSE/AACSR
ACSR MOOSE
ACSR MOOSE
ACSR TWIN
MOOSE
ACSR TWIN
MOOSE
AAAC QUAD
MOOSE
AAAC QUAD
MOOSE
1
AZARA
SILCHAR
2
BALIPARA
MISA
POWERGRID
95.4
1
BALIPARA
MISA
POWERGRID
95.4
2
BALIPARA
BALIPARA
RANAGANADI
RANAGANADI
POWERGRID
POWERGRID
166.3
166.3
1
2
6
BONGAIGAON
BALIPARA
POWERGRID
289.8
1
7
BONGAIGAON
BALIPARA
POWERGRID
289.8
2
8
BONGAIGAON
BALIPARA
POWERGRID
305.0
3
9
BONGAIGAON
BALIPARA
POWERGRID
305.0
4
10
BONGAIGAON
BTPS
POWERGRID
3.1
1
TWIN MOOSE
11
BONGAIGAON
BTPS
POWERGRID
3.1
2
TWIN MOOSE
POWERGRID
218
1
ACSR TWIN
MOOSE
POWERGRID
218
2
ACSR TWIN
MOOSE
POWERGRID
221
3
AAAC QUAD
MOOSE
POWERGRID
221
4
AAAC QUAD
MOOSE
3
4
5
BONGAIGAON
12
BONGAIGAON
13
BONGAIGAON
14
BONGAIGAON
15
NEW
SILIGURI
(BINAGURI)
NEW
SILIGURI
(BINAGURI)
NEW
SILIGURI
(BINAGURI)
NEW
SILIGURI
(BINAGURI)
16
BYRNIHAT
SILCHAR
NETCL
217.14
1
17
PALLATANA
SILCHAR
NETCL
246
1
18
PALLATANA
SILCHAR
NETCL
246
2
ACSR TWIN
MOOSE
ACSR TWIN
MOOSE
ACSR TWIN
MOOSE
LIST-2: 400 KV LINE (CHARGED AT 220 KV) DETAILS OF NORTH
EASTERN REGION
SR.
NO.
1
FROM
MARIANI
TO
UTILITY
KM
CKT
CONDUCTOR
KATHALGURI
POWERGRID
162.9
1
ACSR TWIN
MOOSE
Page 26 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
2
MISA
NEW
MARIANI
POWERGRID
222.7
1
3
MISA
MARIANI
POWERGRID
220.0
1
4
NEW
MARIANI
KATHALGURI
POWERGRID
160.5
1
ACSR TWIN
MOOSE
ACSR TWIN
MOOSE
ACSR TWIN
MOOSE
LIST-3: 400 KV LINE CHARGED AT 132 KV
SR.
NO.
1
FROM
PALATANA
TO
UTILITY
KM
CKT
CONDUCTOR
SURJAMANIN
AGAR
POWERGRID
37
1
ACSR TWIN
MOOSE
LIST-4: 220 KV LINE DETAILS OF NORTH EASTERN REGION
SR.
NO.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
FROM
TO
AGIA
AGIA
AGIA
AGIA
AZARA
AZARA
BALIPARA
BONGAIGAON
AZARA
BOKO
BTPS
BTPS
BOKO
SARUSAJAI
SAMAGURI
SALAKATI
DEOMALI
KATHALGURI
KATHALGURI
KATHALGURI
MISA
MISA
MISA
MISA
MISA
MISA
MISA
NTPS
NTPS
TINSUKIA
TINSUKIA
DIMAPUR
DIMAPUR
KOPILI
KOPILI
KOPILI
BYRNIHAT
BYRNIHAT
TINSUKIA
TINSUKIA
BIRPARA
(ER)
BIRPARA
(ER)
BTPS
BTPS
SALAKATI
SALAKATI
SALAKATI
SALAKATI
UTILITY
KM
CKT
CONDUCTOR
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
POWERGRID
ARUNACHAL
PRADESH
AEGCL
AEGCL
POWERGRID
POWERGRID
POWERGRID
POWERGRID
POWERGRID
MeECL
MeECL
AEGCL
AEGCL
1.0
70.0
67.0
67.0
38
48
55.0
5.4
1
1
1
2
1
1
1
1
AAAC ZEBRA
AAAC ZEBRA
AAAC ZEBRA
AAAC ZEBRA
AAAC ZEBRA
AAAC ZEBRA
SINGLE ZEBRA
SINGLE ZEBRA
19.0
1
SINGLE ZEBRA
22.0
22.0
121.9
121.9
72.8
72.8
75.9
115.0
115.0
40.0
40.0
1
2
1
2
1
2
3
1
2
1
2
SINGLE ZEBRA
SINGLE ZEBRA
ACSR ZEBRA
ACSR ZEBRA
ACSR ZEBRA
ACSR ZEBRA
AAAC ZEBRA
SINGLE ZEBRA
SINGLE ZEBRA
SINGLE ZEBRA
SINGLE ZEBRA
POWERGRID
160.0
1
SINGLE ZEBRA
POWERGRID
160.0
2
SINGLE ZEBRA
AEGCL
POWERGRID
2.7
2.7
1
2
ACSR ZEBRA
ACSR ZEBRA
Page 27 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
25
26
27
28
29
30
31
SAMAGURI
SAMAGURI
SAMAGURI
SAMAGURI
SARUSAJAI
SARUSAJAI
SARUSAJAI
JAWAHARN
AGAR
MARIANI
MISA
MISA
JAWAHARN
AGAR
LANGPI
SAMAGURI
AEGCL
120
1
AAAC ZEBRA
AEGCL
POWERGRID
POWERGRID
164.0
34.4
34.4
1
1
2
AAAC DEER
ACSR ZEBRA
ACSR ZEBRA
AEGCL
10
1
AAAC ZEBRA
AEGCL
AEGCL
108.0
124.0
1
2
AAAC ZEBRA
AAAC ZEBRA
LIST-5: 132 KV LINE DETAILS OF POWERGRID IN NORTH EASTERN
REGION
SR.
NO.
1
2
3
4
5
6
7
8
9
10
11
FROM
TO
UTILITY
KM
CKT
CONDUCTOR
66.1
1
AAAC PANTHER
AIZWAL
KOLASIB
POWERGRID
AIZWAL
ZEMABAWK
POWERGRID
7.0
1
ACSR PANTHER
BADARPUR
JIRIBAM
POWERGRID
67.2
1
AAAC PANTHER
BADARPUR
KUMARGHAT
POWERGRID
118.5
1
AAAC PANTHER
BADARPUR
PANCHGRAM
POWERGRID
1.0
1
BADARPUR
KOLASIB
POWERGRID
172.3
1
AAAC PANTHER
ACSR PANTHER
BADARPUR
SILCHAR
POWERGRID
19
1
ACSR PANTHER
BADARPUR
SILCHAR
POWERGRID
19
2
ACSR PANTHER
DIMAPUR
DOYANG
POWERGRID
92.5
1
ACSR PANTHER
DIMAPUR
DOYANG
POWERGRID
92.5
2
ACSR PANTHER
HAFLONG
POWERGRID
100.0
1
ACSR PANTHER
POWERGRID
1.5
1
ACSR PANTHER
IMPHAL
JIRIBAM
IMPHAL
(MANIPUR)
DIMAPUR
POWERGRID
168.9
1
ACSR PANTHER
JIRIBAM
AIZWAL
POWERGRID
170.0
1
ACSR PANTHER
12
13
14
15
16
17
18
19
20
21
IMPHAL
22
23
24
KHLEIHRIAT
25
26
27
JIRIBAM
LOKTAK
POWERGRID
82.4
2
ACSR PANTHER
KHANDONG
HAFLONG
POWERGRID
64.0
1
ACSR PANTHER
KHANDONG
KOPILI
POWERGRID
10.9
1
ACSR PANTHER
KHANDONG
KOPILI
POWERGRID
10.9
2
ACSR ZEBRA
KHLEIHRIAT
KHANDONG
POWERGRID
42.5
1
KHLEIHRIAT
KHANDONG
POWERGRID
40.9
2
ACSR PANTHER
ACSR PANTHER
KHLEIHRIAT
POWERGRID
76.6
1
ACSR PANTHER
POWERGRID
5.5
1
KUMARGHAT
BADARPUR
KHLEIHRIAT
(MeECL)
AIZWAL
POWERGRID
131.0
1
ACSR PANTHER
KUMARGHAT
R C NAGAR
104.0
1
ACSR PANTHER
LEKHI
NIRJULI
4
1
LOKTAK
IMPHAL
POWERGRID
POWERGRID,
DoP,AP
POWERGRID
35.0
1
ACSR PANTHER
NIRJULI
GOHPUR
POWERGRID
42.5
1
ACSR PANTHER
Page 28 of 103
ACSR PANTHER
ACSR PANTHER
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
PANCHGRAM
SURAJMANI
NAGAR
BADARPUR
R C NAGAR
AGARTALA
R C NAGAR
AGARTALA
32
33
RANGANADI
LEKHI
RANGANADI
ZIRO
34
35
RANGIA
36
37
28
PALLATANA
29
30
31
ACSR PANTHER
37
1
POWERGRID
1.0
1
AAAC PANTHER
POWERGRID
8.4
1
ACSR PANTHER
POWERGRID
POWERGRID,
DoP,AP
POWERGRID
8.4
2
ACSR PANTHER
18
3
ACSR PANTHER
44.5
1
ACSR PANTHER
POWERGRID
49
1
ACSR PANTHER
POWERGRID
49.2
1
ACSR PANTHER
SILCHAR
MOTONGA
GELYPHU
(BHUTAN)
SRIKONA
POWERGRID
1
1
ACSR PANTHER
SILCHAR
SRIKONA
POWERGRID
1
2
AAAC PANTHER
SALAKATI
LIST-6: 132 KV LINE DETAILS OF NEEPCO IN NORTH EASTERN
REGION
SR.
NO.
1
2
3
FROM
BALIPARA
BHALUKPANG
KHUPI
TO
BHALUKPANG
KHUPI
KIMI
UTILITY
KM
CKT
CONDUCTOR
NEEPCO
NEEPCO
NEEPCO
35
32
8
1
1
1
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
LIST-7: 132 KV LINE DETAILS OF AEGCL IN NORTH EASTERN
REGION
SR.
NO.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
FROM
B CHARIALI
BALIPARA
BALIPARA
BOKAJAN
BORNAGAR
CTPS
DEPOTA
DEPOTA
DHALIGAON
DHALIGAON
DHALIGAON
DHALIGAON
DHALIGAON
DHALIGAON
DIBRUGARH
DIPHU
DISPUR
TO
GOHPUR
DEPOTA
GOHPUR
DIMAPUR
RANGIA
JAGIROAD
B CHARIALI
SAMAGURI
BTPS
BTPS
NALBARI
BORNAGAR
ASHOK PAPER
MILL
BRPL
MORAN
SANKARDEV NGR
CTPS
UTILITY
KM
CKT
CONDUCTOR
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
51.0
28.0
106.0
5.0
86.0
35.0
57.0
45.0
22.0
22.0
106.0
41.0
1
1
1
1
1
1
1
1
1
2
1
1
AEGCL
37.0
1
ACSR PANTHER
ACSR PANTHER
SINGLE ZEBRA
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
AEGCL
AEGCL
AEGCL
AEGCL
1.0
36.0
72.0
29.0
1
1
1
1
Page 29 of 103
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
43
39
40
41
42
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
GOHPUR
GOHPUR
GOLAGHAT
GOSAIGAON
GOSAIGAON
HAFLONG
JAGIROAD
JIRIBAM
JORHAT
KAHELIPARA
KAHELIPARA
KAHELIPARA
KAHELIPARA
KAHELIPARA
KAHELIPARA
LANKA
LTPS
LTPS
LTPS
LTPS
LTPS
LTPS
MARIANI
MARIANI
MARIANI
MOKOKCHUNG
N LAKHIMPUR
NALBARI
NARENGI
NAZIRA
PANCHGRAM
PANCHGRAM
RANGIA
RANGIA
RANGIA
RANGIA
ROWTA
ROWTA
SAMAGURI
SILCHAR
SIPAJHAR
SISUGRAM
SRIKONA
TINSUKIA
TINSUKIA
N LAKHIMPUR
N LAKHIMPUR
BOKAJAN
DHALIGAON
GAURIPUR
HAFLONG
HPC
PAILAPOOL
BOKAKHAT
NARENGI
SARUSAJAI
SARUSAJAI
SARUSAJAI
SARUSAJAI
DISPUR
DIPHU
NTPS
NTPS
NAZIRA
NAZIRA
MARIANI
MORAN
JORHAT
JORHAT
GOLAGHAT
MARIANI
DHEMAJI
RANGIA
CTPS
SIBSAGAR
SRIKONA
SILCHAR
SISUGRAM
SIPAJHAR
KAHELIPARA
ROWTA
DEPOTA
DEPOTA
SANKARDEV NGR
DULLAVCHERRA
ROWTA
KAHELIPARA
PAILAPOOL
LEDO
DIBRUGARH
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
Page 30 of 103
77.0
77.0
65.0
65.0
62.0
1.0
5.0
15.0
89.0
12.0
4.0
4.0
4.0
4.0
3.0
71.6
60.0
60.0
22.0
22.0
80.0
39.0
20.0
20.0
45.0
19.0
63.0
22.0
20.0
13.0
19.0
30.0
33.0
38.0
46.0
108.0
72.0
64.0
61.0
50.0
44.0
12.0
35.0
53.0
53.0
1
1
1
1
1
1
1
1
1
1
1
2
3
4
1
1
1
2
1
2
1
1
1
2
1
1
1
1
1
1
1
1
1
1
1
1
1
2
1
1
1
1
1
1
1
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
TINSUKIA
63
NTPS
AEGCL
43.0
1
ACSR PANTHER
LIST-8: 132 KV LINE DETAILS OF MANIPUR IN NORTH EASTERN
REGION
SR.
NO.
1
2
3
4
5
6
7
8
9
10
11
12
FROM
CHURACHANDPUR
IMPHAL
IMPHAL MANIPUR
KAKCHING
KONGBA
LOKTAK
LOKTAK
NINGTHOUKONG
NINGTHOUKONG
NINGTHOUKONG
RENGPANG
YAINGANGPOKPI
TO
UTILITY
KM
CKT
KAKCHING
IMPHAL(PG)
KARONG
KONGBA
YAINGANGPOKPI
NINGTHOUKONG
RENGPANG
CHURACHANDPUR
CHURACHANDPUR
IMPHAL(PG)
JIRIBAM
IMPHAL MANIPUR
MANIPUR
MANIPUR
MANIPUR
MANIPUR
MANIPUR
MANIPUR
MANIPUR
MANIPUR
MANIPUR
MANIPUR
MANIPUR
MANIPUR
38.0
2.3
60.0
45.0
33.0
20.0
42.0
23.0
23.0
26.2
40.4
42.0
1
2
1
1
1
1
1
1
2
1
1
1
CONDUCTOR
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
LIST-9: 132 KV LINE DETAILS OF TSECL IN NORTH
SR.
NO.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
FROM
TO
UTILITY
KM
CKT
CONDUCTOR
8.0
35.0
35.0
14.0
7.0
45.0
25.0
15.0
32.0
18.0
1.0
45.0
31.0
35.0
1
1
2
1
1
1
1
1
1
1
1
1
1
1
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
6
1
40.0
1
AGARTALA
AGARTALA
AGARTALA
BARAMURA
BODHJ NGR
DHALABIL
GAMAITILLA
JIRANIA
KAMALPUR
P K BARI
P K BARI
P K BARI
P K BARI
P K BARI
BODHJ NGR
ROKHIA
ROKHIA
GAMAITILLA
JIRANIA
AGARTALA
AMBASA
BARAMURA
DHALABIL
KAILASHOR
KUMARGHAT
AMBASA
KAMALPUR
DHARMA NAGAR
PALLATANA
UDAIPUR
TSECL
TSECL
TSECL
TSECL
TSECL
TSECL
TSECL
TSECL
TSECL
TSECL
TSECL
TSECL
TSECL
TSECL
TSECL
ROKHIA
UDAIPUR
TSECL
Page 31 of 103
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
LIST-10: 132 KV LINE DETAILS OF NAGALAND IN NORTH EASTERN
REGION
SR.
NO.
1
2
3
4
5
6
7
8
FROM
DIMAPUR
DIMAPUR
DOYANG
KOHIMA
KOHIMA
KOHIMA
MELURI
WOKHA
TO
DIMAPUR (PGCIL)
DIMAPUR (PGCIL)
MOKOKCHUNG
MELURI
DIMAPUR (PGCIL)
WOKHA
KIPHIRI
DOYANG
UTILITY
KM
CK
T
CONDUCTOR
NAGALAND
NAGALAND
NAGALAND
NAGALAND
NAGALAND
NAGALAND
NAGALAND
NAGALAND
1
1
30
74
58
58
42
13
1
2
1
1
1
1
1
1
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
LIST-11: 132 KV LINE DETAILS OF MIZORAM IN NORTH EASTERN
REGION
SR.
NO.
1
2
3
4
5
FROM
ZUANGTUI
SERCHIP
LUNGLEI
AIZWAL
BHAIRABI
TO
SAITUAL
ZUANGTUI
SERCHIP
LUANGMUAL
KOLASIB
UTILITY
KM
CK
T
CONDUCTOR
MIZORAM
MIZORAM
MIZORAM
MIZORAM
MIZORAM
50.0
54.0
69.0
6.7
30.0
1
1
1
1
1
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
LIST-12: 132 KV LINE DETAILS OF MeECL IN NORTH EASTERN
REGION
SR.
NO.
1
2
3
4
5
6
7
8
9
10
11
FROM
TO
UTILITY
KM
CK
T
1
AGIA
NAGALBIBRA
MeECL
92.0
EPIP I
SHYAM CENTURY
MeECL
0.15
1
EPIP I
MAITHAN
MeECL
0.2
1
EPIP I
SAI PRAKASH
MeECL
4.0
1
EPIP I
GREYSTONE
MeECL
0.7
1
EPIP II
EPIP I
MeECL
2.5
1
EPIP II
EPIP I
MeECL
2.5
2
EPIP II
KILLING
MeECL
10.0
1
EPIP II
KILLING
10.0
2
EPIP II
TRISHUL
MeECL
MeECL
0.2
1
EPIP II
NALARI
MeECL
0.2
1
Page 32 of 103
CONDUCTOR
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
KHLEIHRIAT
MeECL
KHLEIHRIAT
MeECL
KHLEIHRIAT
MeECL
KHLEIHRIAT
MeECL
LUMSHNONG
LUMSHNONG
MeECL
MeECL
LESHKA
MeECL
LESHKA
24.0
1
ACSR PANTHER
26.0
1
ACSR PANTHER
26.0
2
ACSR PANTHER
2
ACSR PANTHER
KHLEIHRIAT
MeECL
5.0
CMCL
MeECL
0.16
1
LUMSHNONG
MCL
MeECL
3.0
1
LUMSHNONG
ADHUNIK CEMENT
MeECL
8.0
1
LUMSHNONG
HILL CEMENT
MeECL
8.0
1
LUMSHNONG
JUD CEMENT
MeECL
2.0
1
LUMSHNONG
GVIL CEMENT
MeECL
2.0
1
MAWLAI
CHEERAPUNJI
MeECL
41.0
1
MAWLAI
NONGSTOIN
MeECL
71.3
1
MAWLAI
NEHU
MeECL
9.2
1
NANGALBIBRA
TURA
MeECL
68.7
1
NEHU
NEIGHRIMS
MeECL
7.0
1
NEHU
KHLEIHRIAT MeECL
MeECL
52.6
1
NEIGHRIMS
KHLEIHRIAT MeECL
MeECL
64.8
1
NONGSTOIN
NANGALBIBRA
MeECL
56.0
1
UMIUM
NEHU
MeECL
7.0
1
UMIUM ST I
UMIUM ST II
MeECL
3.0
1
UMIUM ST I
MAWLAI
MeECL
12.0
1
UMIUM ST I
UMIUM
5.0
1
UMIUM ST I
MAWNGAP
MeECL
MeECL
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
33
1
ACSR PANTHER
UMIUM ST I
MAWNGAP
MeECL
33
2
ACSR PANTHER
UMIUM ST III
UMIUM ST I
MeECL
17.5
1
UMIUM ST III
UMIUM ST I
MeECL
17.5
2
UMIUM ST IV
UMIUM ST III
MeECL
8.0
1
UMIUM ST IV
UMIUM ST III
MeECL
8.0
2
UMTRU
UMIUM ST III
MeECL
41.2
1
UMTRU
UMIUM ST III
MeECL
41.2
2
UMTRU
UMIUM ST IV
MeECL
37.6
1
UMTRU
UMIUM ST IV
MeECL
37.6
2
UMTRU
EPIP II
MeECL
0.7
1
UMTRU
EPIP II
MeECL
0.7
2
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
LIST-13: 132 KV LINE DETAILS OF AP IN NORTH EASTERN REGION
SR.
NO.
1
2
3
4
FROM
TO
UTILITY
KM
CK
T
CONDUCTOR
AGBPP
DEOMALI
AP
19
1
ACSR ZEBRA
DAPORIJO
ALONG
AP
81.7
1
HOZ
CHIPMHU
AP
30
1
ACSR PANTHER
ACSR PANTHER
LEKHI
HOZ
AP
18
1
ACSR PANTHER
Page 33 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
5
ZIRO
DAPORIJO
AP
87.2
1
ACSR PANTHER
LIST-14: 66 KV LINE DETAILS OF NORTH EASTERN REGION
SR.
NO.
FROM
TO
UTILITY
KM
CKT CONDUCTOR
AEGCL
TSECL
TSECL
TSECL
TSECL
TSECL
TSECL
TSECL
AEGCL
34.0
30.0
24.0
8.0
36.0
29.0
8.0
15.0
39.0
1
1
1
1
1
1
1
1
1
1
2
3
4
5
6
7
8
9
AGIA
AMARPUR
BADARGHAT
BADARGHAT
BAGAFA
BAGAFA
BARAMURA
BELONIA
BOKAJAN
LAKHIPUR
GUMTI
ROKHIA
AGARTALA
SATCHAND
UDAIPUR
TELIAMURA
BAGAFA
DIPHU
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
DIMAPUR
POWER HOUSE
NAGALAND
4.0
1
DIMAPUR
DIMAPUR
DULLAVCHERRA
FCI
FCI
GOKULNAGAR
GOLAGHAT
GOLAGHAT
GUMTI
KHIPHIRE
KHIPHIRE
KOLASIB
MARIANI
MARIANI
MARIANI
MARIANI
SINGRIJAN
SINGRIJAN
PATHARKANDI
NTPS
NTPS
BADARGHAT
BOKAJAN
BOKAJAN
UDAIPUR
LIKHIMRO
LIKHIMRO
VAIRENGTE
GOLAGHAT
GOLAGHAT
NAZIRA
NAZIRA
NAGALAND
NAGALAND
AEGCL
AEGCL
AEGCL
TSECL
AEGCL
AEGCL
TSECL
NAGALAND
NAGALAND
MIZORAM
AEGCL
AEGCL
AEGCL
AEGCL
5.4
5.4
....
3.0
3.0
12.0
64.0
64.0
45.0
35.0
35.0
35.0
40.0
40.0
54.0
54.0
1
2
1
1
2
1
1
2
1
1
2
1
1
2
1
2
27
28
29
30
MOKOKCHUNG
ZUNHEBOTO
NAGALAND
46.0
1
MOKOKCHUNG
MOKOKCHUNG
NAGINIMORA
NAZIRA
NAZIRA
NITO FARM
PATHARKANDI
POWER HOUSE
RABINDRA
NAGAR
TULI
TUENSANG
TIZIT
NTPS
NTPS
DAIRY FARM
ADAMTILLA
DAIRY FARM
NAGALAND
NAGALAND
NAGALAND
AEGCL
AEGCL
NAGALAND
AEGCL
NAGALAND
56.3
50.4
44.0
74.0
74.0
12.0
....
5.0
1
1
1
1
2
1
1
1
TSECL
38.0
1
31
32
33
34
35
36
BELONIA
Page 34 of 103
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
37
ROKHIA
38
SATCHAND
39
SINGRIJAN
40
41
42
43
44
45
46
47
48
SINGRIJAN
TELIAMURA
TINSUKIA
TINSUKIA
TINSUKIA
TIZIT
TUENSANG
TULI
UDAIPUR
RABINDRA
NAGAR
SABROOM
GANESH
NAGAR
CHUMUKIDIMA
AMARPUR
RUPAI
NTPS
NTPS
MON
KHIPHIRE
NAGINIMORA
GOKULNAGAR
TSECL
23.0
1
TSECL
15.0
1
NAGALAND
21.4
1
NAGALAND
TSECL
AEGCL
AEGCL
AEGCL
NAGALAND
NAGALAND
NAGALAND
TSECL
7.9
35.0
25.0
36.0
36.0
31.0
55.7
33.0
31.0
1
1
1
1
2
1
1
1
1
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
ACSR WOLF
LIST-15: SHUNT COMPENSATED LINES IN NORTH EASTERN REGION
SR.
NO.
1
2
3
4
5
6
7
8
9
10
11
12
SENDING RECEIVING
CKT END LINE
END LINE
REACTOR REACTOR
FROM
TO
UTILITY
KM
BONGAIGAON
BONGAIGAON
BONGAIGAON
BONGAIGAON
MISA
MISA
PALLATANA
PALLATANA
BALIPARA
BALIPARA
BALIPARA
BALIPARA
NEW MARIANI
MARIANI
SILCHAR
SILCHAR
POWERGRID
POWERGRID
POWERGRID
POWERGRID
POWERGRID
POWERGRID
NETCL
NETCL
289.9
289.9
305
305
382.9
220
247
247
1
2
3
4
1
1
1
2
50
50
63
63
50
50
63
63
63
63
63
63
NIL
NIL
50
50
RANGANADI
RANGANADI
SILCHAR
SILCHAR
BALIPARA
BALIPARA
AZARA
BYRNIHAT
POWERGRID
POWERGRID
NETCL
NETCL
166.3
166.3
264
217.1
1
2
1
1
50
50
63
63
50
50
63
63
LIST-16: SHUNT COMPENSATED INTER – REGIONAL LINES IN
NORTH EASTERN REGION
SR.
NO.
FROM
1
BONGAIGAON
2
BONGAIGAON
TO
BINAGURI
(ER)
BINAGURI
(ER)
UTILITY
KM
CKT
SENDING
END LINE
REACTOR
RECEIVING
END LINE
REACTOR
POWERGRID
218
1
63
NIL
POWERGRID
218
2
63
NIL
Page 35 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
LIST-17: INTER-STATE LINE DETAILS OF NORTH EASTERN REGION
SR.
NO.
CONNECTING
STATES
1
ARUNACHAL –
ASSAM
2
ASSAM –
MEGHALAYA
ASSAM NAGALAND
3
ASSAM –
TRIPURA
4
5
6
7
8
ASSAM –
MANIPUR
ASSAM –
MIZORAM
MIZORAM –
MANIPUR
MIZORAM –
TRIPURA
NAGALAND –
MANIPUR
OWNED BY
FROM
TO
KV
KM
CKTS
POWERGRID
RANGANADI
BALIPARA
400
166.3
D/C
ARUNACHAL PRADESH
NEEPCO
POWERGRID
POWERGRID
POWERGRID
AEGCL & MeECL
AEGCL & MeECL
AEGCL & MeECL
AEGCL & MeECL
POWERGRID
AEGCL & NAGALAND
AEGCL
AEGCL & NAGALAND
DEOMALI
KHUPI
NIRJULI
BADARPUR
KHANDONG
PANCHGRAM
SARASUJAI
AGIA
KAHILIPARA
MISA
MARIANI
BOKAJAN
BOKAJAN
KATHALGURI
BALIPARA
GOHPUR
KHLIEHRIET
KHLIEHRIET
LUMSHNONG
UMTRU
NANGALBIBRA
UMTRU
DIMAPUR
MOKOKCHUNG
DIMAPUR
DIMAPUR
220
132
132
132
132
132
132
132
132
220
132
132
66
19.0
67.2
42.5
76.6
42.5
23.4
37.0
9.0
123.5
50.0
5.0
8.0
S/C
S/C
S/C
S/C
D/C
S/C
D/C
S/C
D/C
D/C
S/C
S/C
S/C
AEGCL & TRIPURA
DULLAVCHERRA
DHARMANAGAR
132
29.0
S/C
POWERGRID
POWERGRID
POWERGRID
AEGCL
BADARPUR
BADARPUR
HAFLONG
PAILAPOOL
KUMARAGHAT
JIRIBAM
JIRIBAM
JIRIBAM
132
132
132
132
118.5
67.2
100.6
15.0
S/C
S/C
S/C
S/C
POWERGRID
BADARPUR
KOLASIB
132
107.2
S/C
POWERGRID
AIZWAL
JIRIBAM
132
172.3
S/C
POWERGRID
AIZWAL
KUMARAGHAT
132
131.0
S/C
POWERGRID
MANIPUR & NAGALAND
DIMAPUR
KOHIMA
IMPHAL
KARONG
132
132
168.9
50.0
S/C
S/C
Page 36 of 103
CONDUCTOR
ACSR TWIN
MOOSE
ACSR ZEBRA
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR ZEBRA
ACSR PANTHER
ACSR PANTHER
ACSR WOLF
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
ACSR PANTHER
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
LIST-18: FIXED, SWITCHABLE AND CONVERTIBLE LINE REACTORS IN NORTH EASTERN REGION.
SR.
NO.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
UTILITY
FROM
TO
POWERGRID
POWERGRID
POWERGRID
POWERGRID
POWERGRID
POWERGRID
POWERGRID
POWERGRID
POWERGRID
POWERGRID
POWERGRID
POWERGRID
POWERGRID
POWERGRID
POWERGRID
POWERGRID
POWERGRID
POWERGRID
POWERGRID
POWERGRID
POWERGRID
POWERGRID
POWERGRID
BALIPARA
BONGAIGAON
BONGAIGAON
BONGAIGAON
BONGAIGAON
BONGAIGAON
BONGAIGAON
BONGAIGAON
BONGAIGAON
BONGAIGAON
BONGAIGAON
MISA
MISA
PALATANA
PALATANA
PALATANA
PALATANA
RANGANADI
RANGANADI
RANGANADI
RANGANADI
SILCHAR
SILCHAR
MISA
BALIPARA
BALIPARA
BALIPARA
BALIPARA
BALIPARA
BALIPARA
BALIPARA
BALIPARA
BINAGURI(ER)
BINAGURI(ER)
KATHALGURI
MARIANI
SILCHAR
SILCHAR
SILCHAR
SILCHAR
BALIPARA
BALIPARA
BALIPARA
BALIPARA
BYRNIHAT
BONGAIGAON
INSTALLED
AT (STATION)
MISA
BONGAIGAON
BONGAIGAON
BALIPARA
BALIPARA
BONGAIGAON
BONGAIGAON
BALIPARA
BALIPARA
BONGAIGAON
BONGAIGAON
MISA
MISA
SILCHAR
SILCHAR
PALLATANA
PALLATANA
RANGANADI
RANGANADI
BALIPARA
BALIPARA
SILCHAR
SILCHAR
KV
MVAR
KM
400
400
400
400
400
400
400
400
400
400
400
220
220
400
400
400
400
400
400
400
400
400
400
50
50
50
63
63
63
63
63
63
63
63
50
50
50
50
63
63
50
50
50
50
63
63
95.4
289.9
289.9
289.9
289.9
305.0
305.0
305.0
305.0
218.0
218.0
382.9
220.0
247
247
247
247
166.3
166.3
166.3
166.3
217.14
N/A
Page 37 of 103
CONVERTIBLE
….
....
....
....
....
TRUE
TRUE
TRUE
TRUE
....
....
....
….
TRUE
TRUE
….
….
….
….
TRUE
TRUE
TRUE
TRUE
FIXED
TRUE
TRUE
TRUE
TRUE
TRUE
….
….
….
….
TRUE
TRUE
TRUE
TRUE
….
….
….
….
TRUE
TRUE
....
....
….
….
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
24
25
POWERGRID
AEGCL
SILCHAR
SILCHAR
AZARA
AZARA
SILCHAR
AZARA
400
400
63
63
264
264
TRUE
NOTE: CONVERTIBLE: LINE REACTORS WHICH CAN BE OPERATED UPON ONLY WHEN LINE IS IN OUT CONDITION.
FIXED
: LINE REACTORS WHICH ARE FIXED AND CANNOT BE OPERATED UPON AS A BUS REACTOR
Page 38 of 103
….
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
LIST-19: BUS REACTORS IN NORTH EASTERN REGION
SR. NO.
UTILITY
INSTALLED AT
(STATION)
KV
RATING
MVAR
MAKE
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
POWERGRID
POWERGRID
POWERGRID
POWERGRID
POWERGRID
POWERGRID
OTPC
NEEPCO
ASSAM
ASSAM
POWERGRID
POWERGRID
TRIPURA
POWERGRID
POWERGRID
POWERGRID
ASSAM
ASSAM
MEGHALAYA
BALIPARA
BALIPARA
BONGAIGAON
BONGAIGAON
MISA
SILCHAR
PALATANA
RANGANADI
MARIANI
SAMAGURI
AIZWAL
KUMARGHAT
DHARMANAGAR
ZIRO
IMPHAL
NEW MARIANI
SAMAGURI
AZARA
BYRNIHAT
400
400
400
400
400
400
400
400
220
220
132
132
132
132
132
132
132
400
400
50
80
2 X 50
2 X 80
50
2 X 63
80
50
2 X 12.5
2 X 12.5
20
20
2X2
20
20
20
2X12.5
63
63
BHEL
BHEL
BHEL
BHEL
BHEL
CGL
BHEL
….
....
....
....
....
....
….
….
….
….
….
STATUS
IN SERVICE
IN SERVICE
IN SERVICE
IN SERVICE
IN SERVICE
IN SERVICE
IN SERVICE
IN SERVICE
IN SERVICE
IN SERVICE
IN SERVICE
IN SERVICE
IN SERVICE
IN SERVICE
IN SERVICE
IN SERVICE
IN SERVICE
IN SERVICE
IN SERVICE
LIST-20: TERTIARY REACTORS ON 33 KV SIDE OF 400/220/33 KV ICTS IN
NORTH EASTERN REGION
SR. NO.
UTILITY
INSTALLED
AT (STATION)
1
POWERGRID
BALIPARA
2
POWERGRID
BONGAIGAON
3
POWERGRID
MISA
INSTALLED
ON
33 KV SIDE OF
ICT I
33 KV SIDE OF
ICT I
33 KV SIDE OF
ICT I
Page 39 of 103
RATING
MVAR
MAKE
STATUS
4 X 25
BHEL
IN SERVICE
2 X 25
BHEL
IN SERVICE
4 X 25
BHEL
IN SERVICE
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
3
3.1
SERIES AND SHUNT CAPACITOR VOLTAGE
CONTROL
INTRODUCTION
3.1.1
Capacitors aid in minimizing operating expenses and allow the utilities to
serve new loads and consumers with a minimum system investment.
Series and shunt capacitors in a power system generate reactive power to
improve power factor and voltage, thereby enhancing the system capacity
and reducing the losses.
3.1.2
In series capacitors the reactive power is proportional to the square of the
load current, thus generating reactive power when it is most needed
whereas in shunt capacitors it is proportional to the square of the voltage.
Series capacitors compensation is usually applied for long transmission
lines and transient stability improvement. Series compensation reduces
net transmission line inductive reactance. The reactive generation I2XC
compensates for the reactive consumption I2X of the transmission line.
This is a self-regulating nature of series capacitors. At light loads series
capacitors have little effect.
3.1.3
There
are
certain
unfavorable aspects of
series
capacitors.
Generally the cost of
installing
series
capacitors is higher than
that of a corresponding
installation of a shunt
capacitor.
3.1.4
This is because the
protective equipment for a
series capacitor is often
more complicated. The
factors which influence
the choice between the
shunt
and
series
capacitors
are
summarized in Table 3.
Page 40 of 103
Table 4. Equipment preference
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
3.1.5
Due to various limitations in the use of series capacitors, shunt
capacitors are widely used in distribution systems. For the same voltage
improvement, the rating of a shunt capacitor will be higher than that of a
series capacitor. Thus a series capacitor stiffens the system, which is
especially beneficial for starting large motors from an otherwise weak
power system, for reducing light flicker caused by large fluctuating load,
etc.
3.2
MeSEB CAPACITY BUILDING AND TRAINING
DOCUMENT SUGGEST (Sub title as given in the PFC
document for corporatization of MeSEB):
3.2.1
Installation of Shunt-capacitors:
Installation of capacitors is a low cost process for reduction of technical
losses. The agricultural load mainly consists of irrigation pump motors.
The PF of pump motors are generally below 0.6, which means the total
reactive power demand of the system is high. The reactive power demand
can be reduced by installation of suitable capacitors. However, proper
maintenance has to be adopted to keep the system in order. In view of the
maintenance problem, reactive compensation technique could be
installed at the distribution transformer centers. Care has to be taken that
it does not lead to over voltage problems during the off peak hours. To
avoid this there should be switch off arrangement in the capacitor bank.
The optimum allocation of LT capacitors at distribution substation by
minimizing a cost function, which includes loss cost in the beneficiary
system and the annual cost of the capacitor bank. The reactive
compensation can also be carried out at the primary distribution feeders
(11 KV) lines. The optimum number, size and location of online capacitors
will depend on the following factors:
•
Type of load.
•
Quantum of load.
•
Load factor.
•
Annual load cycle.
•
Power factor.
3.3
AS PER THE ASSAM GAZETTE, EXTRAORDINARY,
FEBRUARY 10, 2005
IN CHAPTER 9: FREQUENCY AND VOLTAGE MANAGEMENT
Sec 9.1 (d) System voltages levels can be affected by Regional operation.
The SLDC shall optimize voltage management by adjusting
transformer taps to the extent available and switching of
Page 41 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
circuits/ capacitors/ reactors and other operational steps.
SLDC will instruct generating stations to regulate MVAr
generation within their declared parameters. SLDC shal also
instruct Distribution Licensees to regulate demand, if
necessary.
LIST-21: SUBSTATIONS IN NER
AGENCY
400KV
220 KV
POWER GRID
ARUNACHAL
PRADESH
AEGCL
4
3
132 KV &
66 KV
11
NIL
1
6
7
1
8
22
31
MANIPUR
NIL
NIL
7
7
MeECL
1
NIL
9
10
MIZORAM
NIL
NIL
6
6
NAGALAND
NIL
NIL
7
7
NEEPCO
1
2
4
7
NHPC
NIL
NIL
1
1
TSECL
1
NIL
9
10
OTPC
1
NIL
NIL
1
TOTAL
9
14
82
105
Page 42 of 103
TOTAL
18
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
LIST-22: SHUNT CAPACITOR DETAILS OF NORTH EASTERN REGION
SR. NO.
UTILITY
SUBSTATION
INSTALLED ON
CAPACITY
(MVAR)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
MeECL
MeECL
MeECL
MeECL
MeECL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
AEGCL
132 KV BUS BAR
132 KV BUS BAR
132 KV BUS BAR
33 KV BUS BAR
33 KV BUS BAR
33 KV BUS BAR
33 KV BUS BAR
33 KV BUS BAR
33 KV BUS BAR
33 KV BUS BAR
33 KV BUS BAR
33 KV BUS BAR
33 KV BUS BAR
33 KV BUS BAR
33 KV BUS BAR
33 KV BUS BAR
33 KV BUS BAR
33 KV BUS BAR
33 KV BUS BAR
12.5
20
20
15
15
2X5
3X5
2X5
1X5
1X10
2X10
2X5
1X5
1X5
2X5
2X10
2X5
2X5
2X10
20
AEGCL
33 KV BUS BAR
2X5
21
22
AEGCL
AEGCL
MAWLAI
EPIP I
EPIP II
EPIP II
EPIP II
BAGHJAB
KAHELIPARA
BARNAGAR
GOSAIGAON
GAURIPUR
RANGIA
MARGHERITA
N LAKHIMPUR
DULLAVCHERRA
DEPOTA
SARUSAJAI
ROWTA
DIPHU
DIBRUGARH
SHANKARDEV
NAGAR
RUPAI
SRIKONA
33 KV BUS BAR
33 KV BUS BAR
2X5
2X5
Total Capacity of NER
Page 43 of 103
273
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
4
TRANSFORMER LOAD TAP CHANGER AND
VOLTAGE CONTROL
4.1
INTRODUCTION
4.1.1
Transformers provide the capability to raise alternating-current
generation voltages to levels that make long-distance power transfers
practical and then lowering voltages back to levels that can be distributed
and used. The ratio of the number of turns in the primary to the number of
turns in the secondary coil determines the ratio of the primary voltage to
the secondary voltage. By tapping the primary or secondary coil at
various points, the ratio between the primary and secondary voltage can
be adjusted. Transformer taps can be either fixed or adjustable under
load through the use of a load-tap changer (LTC). Tap capability is
selected for each application during transformer design.
4.1.2
The OLTC alters the power
transformer turns ratio in a
number of pre defined steps
and in that way changes the
secondary side voltage.
4.1.3
Each step usually represents
a change in LV side no-load
voltage of approximately 0.51.7%. Standard tap changers
offer between ± 9 to ± 17
steps (i.e. 19 to 35 positions).
The
automatic
voltage
regulator (AVR) is designed
to
control
a
power
transformer with a motor
driven on-load tap-changer.
Fig 13. Switching principle of LTC
4.1.4
Typically the AVR regulates voltage at the secondary side of the power
transformer. The control method is based on a step-by-step principle
which means that a control pulse, one at a time, will be issued to the onload tap-changer mechanism to move it up or down by one position.
4.1.5
The pulse is generated by the AVR whenever the measured voltage, for a
given time, deviates from the set reference value by more than the preset
dead band (i.e. degree of insensitivity). Time delay is used to avoid
Page 44 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
unnecessary operation during short voltage deviations from the pre-set
value.
4.1.6
Transformer-tap changers can be used for voltage control, but the control
differs from that provided by reactive sources. Transformer taps can
force voltage up (or down) on one side of a transformer, but it is at the
expense of reducing (or raising) the voltage on the other side. The
reactive power required to raise (or lower) voltage on a bus is forced to
flow through the transformer from the bus on the other side.
4.1.7
The reactive power consumption of a transformer at rated current is
within the range 0.05 to 0.2 p.u. based on the transformer ratings. Fixed
taps are useful when compensating for load growth and other long-term
shifts in system use. LTCs are used for more-rapid adjustments, such as
compensating for the voltage fluctuations associated with the daily load
cycle. While LTCs could potentially provide rapid voltage control, their
performance is normally intentionally degraded. With an LTC, tap
changing is accomplished by opening and closing contacts within the
transformer’s tap changing mechanism.
4.2
AS PER THE ASSAM GAZETTE, EXTRAORDINARY,
FEBRUARY 10, 2005
IN CHAPTER 9: FREQUENCY AND VOLTAGE MANAGEMENT
Sec 9.1(d) System voltages levels can be affected by Regional operation.
The SLDC shall optimise voltage management by adjusting transformer
taps to the extent available and switching of circuits/ capacitors/ reactors
and other operational steps. SLDC will instruct generating stations to
regulate MVAr generation within their declared parameters. SLDC shall
also instruct Distribution Licensees to regulate demand, if necessary.
Page 45 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
LIST-23: ICT DETAILS OF POWERGRID IN NORTH EASTERN REGION
STEP
%AGE
KV
SL.
NO.
SUBSTATION
AGENCY
ICT
NO.
MVA
KV
RATIO
MAKE
TT
NT
1
BALIPARA
POWERGRID
01
315
400/220
/33 kV
TELK
17
9
1.25
5
10
2
BONGAIGAON
POWERGRID
01
315
400/220
/33 kV
TELK
17
9
1.25
5
12
3
SILCHAR
POWERGRID
01
200
CGL
17
9
1.25
5
9B
4
SILCHAR
POWERGRID
01
200
CGL
17
9
1.25
5
9B
5
MISA
POWERGRID
01
315
TELK
17
9
1.25
5
05
6
MISA
POWERGRID
02
315
CGL
17
9
1.25
5
05
7
DIMAPUR
POWERGRID
01
100
TELK
17
13
1.25
2.75
12
8
DIMAPUR
POWERGRID
02
100
ALSTOM
17
13
1.25
2.75
12
9
NIRJULI
POWERGRID
01
10
132 /33
kV
KANOHAR
ELECT.
17
9
1.25
1.65
09
10
NIRJULI
POWERGRID
01
10
132 /33
kV
BBL
5
3
1.25
1.65
03
11
SALAKATI
POWERGRID
01
50
NGEF
17
13
1.25
2.75
16
12
SALAKATI
POWERGRID
02
50
EMCO
17
13
1.25
2.75
16
13
ZIRO
POWERGRID
01
15
132 /33
kV
AREVA
/ALSTOM
17
9
1.25
1.65
02
14
KOPILI
POWERGRID
01
160
220/132
kV
….
….
….
….
….
13
15
IMPHAL
POWERGRID
01
50
132/33
kV
….
….
….
….
….
….
16
IMPHAL
POWERGRID
02
50
132/33
kV
….
….
….
….
….
….
400/132
kV
400/132
kV
400/220
/33 kV
400/220
kV
220/132
kV
220/132
kV
220/132
kV
220/132
kV
LIST-24: ICT DETAILS OF NEEPCO IN NORTH EASTERN REGION
SL.
NO.
SUBSTATION
AGENCY
ICT
NO.
MVA
1
RHEP
NEEPCO
01
7.5
2
RHEP
NEEPCO
02
7.5
Page 46 of 103
KV
RATIO
132/33
KV
132/33
KV
STEP
%AGE
KV
MAKE
TT
NT
PT
….
….
….
….
….
02
….
….
….
….
….
03
PT
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
3
BALIPARA
NEEPCO
01
50
4
KOPILI
NEEPCO
01
60
5
RHEP
NEEPCO
01
360
6
RHEP
NEEPCO
02
360
220/132
KV
220/132
KV
400/132
KV
400/132
KV
….
….
….
….
….
09
….
….
….
….
….
09
….
….
….
….
….
10
….
….
….
….
….
09
STEP
%AGE
KV
PT
LIST-25: ICT DETAILS OF NHPC IN NORTH EASTERN REGION
SL.
NO.
SUBSTATION
AGENCY
ICT
NO.
MVA
KV
RATIO
MAKE
TT
NT
1
LOKTAK
NHPC
01
5
132/33
KV
….
….
….
….
….
02
STEP
%AGE KV
PT
LIST-26: ICT DETAILS OF ARUNACHAL PRADESH IN NORTH EASTERN
REGION
SL.
NO.
SUBSTATION
1
ALONG
2
DAPORIJO
3
DAPORIJO
4
DEOMALI
5
DEOMALI
6
LEKHI
7
LEKHI
AGENCY
ARUNACHAL
PRADESH
ARUNACHAL
PRADESH
ARUNACHAL
PRADESH
ARUNACHAL
PRADESH
ARUNACHAL
PRADESH
ARUNACHAL
PRADESH
ARUNACHAL
PRADESH
ICT
NO.
MVA
01
15
01
5
02
5
01
100
01
16
01
15
01
20
KV
RATIO
132/33
KV
132/33
KV
132/33
KV
220/
132 kV
132/33
KV
132/33
KV
132/33
KV
MAKE
TT
NT
….
….
….
….
….
03
….
….
….
….
….
02
….
….
….
….
….
02
….
….
….
….
….
09
….
….
….
….
….
04
….
….
….
….
….
05
….
….
….
….
….
05
STEP
%AGE KV
PT
LIST-27: ICT DETAILS OF AEGCL IN NORTH EASTERN REGION
SL.
NO.
SUBSTATION
AGENCY
ICT
NO.
MVA
1
AGIA
AEGCL
01
50
2
AGIA
AEGCL
02
100
2
AGIA
AEGCL
01
40
3
AGIA
AEGCL
01
12.5
Page 47 of 103
kV
RATIO
220/132
kV
220/132
kV
132/33
kV
132/33
kV
MAKE
TT
NT
….
….
….
….
….
….
….
….
….
….
….
05
….
….
….
….
….
05
….
….
….
….
14
….
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
….
….
….
….
….
….
….
….
….
….
….
….
….
05
….
….
….
….
….
05
….
….
….
….
….
05
….
….
….
….
….
05
….
….
….
….
….
09
….
….
….
….
….
05
….
….
….
….
….
05
….
….
….
….
….
17
….
….
….
….
….
17
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
05
….
….
….
….
….
05
….
….
….
….
….
….
….
….
….
….
….
….
4
AZARA
AEGCL
01
315
400/220
EMCO
5
AZARA
AEGCL
02
315
400/220
EMCO
AEGCL
01
12.5
AEGCL
01
16
6
7
ASHOK PAPER
MILL
ASHOK PAPER
MILL
8
BAGHJHAP
AEGCL
01
16
9
BAGHJHAP
AEGCL
02
16
10
BALIPARA
AEGCL
01
50
11
BOKO
AEGCL
01
10
12
BOKO
AEGCL
02
10
13
B CHARIALI
AEGCL
01
16
14
B CHARIALI
AEGCL
02
16
15
BORNAGAR
AEGCL
01
25
16
BORNAGAR
AEGCL
02
25
17
BOKAKHAT
AEGCL
01
16
18
BOKAKHAT
AEGCL
02
16
19
BOKAJAN
AEGCL
01
16
20
BTPS
AEGCL
01
10
21
BTPS
AEGCL
02
10
22
BTPS
AEGCL
01
80
23
BTPS
AEGCL
02
80
24
BTPS
AEGCL
03
160
25
CTPS
AEGCL
01
16
26
CTPS
AEGCL
01
30
27
DEPOTA
AEGCL
01
31.5
28
DEPOTA
AEGCL
02
31.5
29
DHALIGAON
AEGCL
01
25
30
DHALIGAON
AEGCL
02
25
Page 48 of 103
132/33
kV
132/33
kV
132/33
kV
132/33
kV
220 /132
kV
220/132
kV
220/132
kV
132/33
kV
132/33
kV
132/33
kV
132/33
kV
132/33
kV
132/33
kV
132/33
kV
132/33
kV
132/33
kV
220/132
kV
220/132
kV
220/132
kV
132/33
kV
132/33
kV
132/33
kV
132/33
kV
132/33
kV
132/33
kV
08
08
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
31
DHEMAJI
AEGCL
01
16
32
DIPHU
AEGCL
01
16
33
DIPHU
AEGCL
02
16
34
DIBRUGARH
AEGCL
01
31.5
35
DIBRUGARH
AEGCL
01
20
36
DIBRUGARH
AEGCL
02
20
37
DISPUR
AEGCL
01
16
38
DISPUR
AEGCL
02
16
39
DULLAVCHERRA
AEGCL
01
3.5
40
DULLAVCHERRA
AEGCL
02
3.5
41
DULLAVCHERRA
AEGCL
03
3.5
42
DULLAVCHERRA
AEGCL
04
3.5
43
DULLAVCHERRA
AEGCL
05
3.5
44
DULLAVCHERRA
AEGCL
06
3.5
45
GAURIPUR
AEGCL
01
10
46
GAURIPUR
AEGCL
02
10
47
GOHPUR
AEGCL
01
16
48
GOHPUR
AEGCL
01
10
49
GOSSAIGAON
AEGCL
01
16
50
GOLAGHAT
AEGCL
01
25
51
GOLAGHAT
AEGCL
02
25
52
HAFLONG
AEGCL
01
10
53
HAFLONG
AEGCL
02
10
54
JORHAT
AEGCL
01
25
55
JORHAT
AEGCL
01
16
56
KAHELIPARA
AEGCL
01
30
57
KAHELIPARA
AEGCL
02
30
58
KAHELIPARA
AEGCL
03
30
Page 49 of 103
132/33
kV
132/66
kV
132/66
kV
132/33
kV
132/33
kV
132/33
kV
132/33
kV
132/33
kV
132/33
kV
132/33
kV
132/33
kV
132/33
kV
132/33
KV
132/33
KV
132/33
kV
132/33
KV
132/33
kV
132/33
kV
132/33
kV
132/33
kV
132/33
kV
132/33
kV
132/33
kV
132/33
KV
132/33
kV
132/33
kV
132/33
kV
132/33
kV
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
08
….
….
….
….
….
08
….
….
….
….
….
08
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
05
….
….
….
….
….
03
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
05
….
….
….
….
….
05
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
05
….
….
….
….
….
05
….
….
….
….
….
06
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
59
KAHELIPARA
AEGCL
01
10
60
KAHELIPARA
AEGCL
02
10
61
LEDO
AEGCL
01
10
62
LEDO
AEGCL
02
10
63
LTPS
AEGCL
01
7.5
64
LTPS
AEGCL
02
7.5
65
MAJULI
AEGCL
01
5.5
66
MARIANI
AEGCL
01
20
67
MARIANI
AEGCL
02
20
68
MARIANI
AEGCL
01
100
69
MARIANI
AEGCL
02
100
70
MORAN
AEGCL
01
16
71
MORAN
AEGCL
02
16
72
NALBARI
AEGCL
01
16
73
NALBARI
AEGCL
02
16
AEGCL
01
10
AEGCL
02
10
74
75
NALKATA
(NORTH
LAKHIMPUR)
NALKATA
(NORTH
LAKHIMPUR)
76
NARENGI
AEGCL
01
25
77
NARENGI
AEGCL
02
25
78
NAZIRA
AEGCL
01
25
79
NTPS
AEGCL
01
25
80
NTPS
AEGCL
02
25
81
PAILAPOOL
AEGCL
01
10
82
PAILAPOOL
AEGCL
02
10
83
PAILAPOOL
AEGCL
03
10
84
PANCHGRAM
AEGCL
01
16
85
PANCHGRAM
AEGCL
02
16
Page 50 of 103
132/33/11
kV
132/33/11
kV
132/33
kV
132/33
kV
132/33
kV
132/33
kV
132/33
kV
132/66
kV
132/66
kV
220/132
kV
220/132
kV
132/33
KV
132/33
kV
132/33
kV
132/33
kV
….
….
….
….
….
02
….
….
….
….
….
02
….
….
….
….
….
06
….
….
….
….
….
06
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
06
….
….
….
….
….
06
….
….
….
….
….
13
….
….
….
….
….
13
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
132/33
kV
….
….
….
….
….
….
132/33
kV
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
06
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
05
….
….
….
….
….
05
….
….
….
….
….
05
….
….
….
….
….
08
….
….
….
….
….
08
132/33
kV
132/33
kV
132/33
kV
132/66
kV
132/66
kV
132/33
kV
132/33
kV
132/33
kV
132/33
kV
132/33
kV
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
86
PANCHGRAM
AEGCL
01
10
87
PANCHGRAM
AEGCL
02
10
88
PAVOI
AEGCL
01
16
89
PAVOI
AEGCL
02
16
90
RANGIA
AEGCL
01
25
91
RANGIA
AEGCL
02
25
92
ROWTA
AEGCL
01
25
93
ROWTA
AEGCL
02
25
94
S NAGAR
AEGCL
01
16
95
S NAGAR
AEGCL
02
16
96
SAMAGURI
AEGCL
01
50
97
SAMAGURI
AEGCL
02
50
98
SAMAGURI
AEGCL
03
50
99
SAMAGURI
AEGCL
01
25
100
SAMAGURI
AEGCL
02
25
101
SARUSAJAI
AEGCL
01
31.5
102
SARUSAJAI
AEGCL
02
31.5
103
SARUSAJAI
AEGCL
01
100
104
SARUSAJAI
AEGCL
02
100
105
SARUSAJAI
AEGCL
03
100
106
SISUGRAM
AEGCL
01
31.5
107
SISUGRAM
AEGCL
02
31.5
108
SIBSAGAR
AEGCL
01
16
109
SIBSAGAR
AEGCL
02
16
110
SIPAJHAR
AEGCL
01
16
111
SIPAJHAR
AEGCL
02
16
112
SRIKONA
AEGCL
01
25
113
SRIKONA
AEGCL
02
25
Page 51 of 103
132/33
kV
132/33
kV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
220/132
kV
220/132
kV
220/132
kV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
220/132
KV
220/132
kV
220/132
kV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
….
….
….
….
….
01
….
….
….
….
….
03
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
03
….
….
….
….
….
03
….
….
….
….
….
03
….
….
….
….
….
03
….
….
….
….
….
04
….
….
….
….
….
05
….
….
….
….
….
12
….
….
….
….
….
12
….
….
….
….
….
12
….
….
….
….
….
06
….
….
….
….
….
06
….
….
….
….
….
06
….
….
….
….
….
06
….
….
….
….
….
10
….
….
….
….
….
12
….
….
….
….
….
11
….
….
….
….
….
06
….
….
….
….
….
06
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
05
….
….
….
….
….
05
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
114
TINSUKIA
AEGCL
01
20
115
TINSUKIA
AEGCL
02
20
116
TINSUKIA
AEGCL
03
20
117
TINSUKIA
AEGCL
01
50
118
TINSUKIA
AEGCL
02
50
132/66
KV
132/66
KV
132/66
KV
220/132
kV
220/132
kV
….
….
….
….
….
02
….
….
….
….
….
04
….
….
….
….
….
03
….
….
….
….
….
16
….
….
….
….
….
16
STEP
%AGE KV
PT
LIST-28: ICT DETAILS OF MANIPUR IN NORTH EASTERN REGION
SL.
NO.
SUBSTATION
AGENCY
ICT
NO.
MVA
1
CHURACHANDPUR
MANIPUR
01
20
2
IMPHAL
MANIPUR
01
20
3
IMPHAL
MANIPUR
02
20
4
IMPHAL
MANIPUR
03
20
5
KAKCHING
MANIPUR
01
20
6
KARONG
MANIPUR
01
20
7
NINGTHOUKHONG
MANIPUR
01
12.5
8
NINGTHOUKHONG
MANIPUR
02
12.5
9
YANGANGPOKPI
MANIPUR
01
20
10
YANGANGPOKPI
MANIPUR
02
20
11
JIRIBAM
MANIPUR
01
6.3
KV
RATIO
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
MAKE
TT
NT
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
….
LIST-29: ICT DETAILS OF MEGHALAYA IN NORTH EASTERN REGION
SL.
NO.
SUBSTATION
AGENCY
ICT
NO.
MVA
1
CHERAPUNJEE
MeECL
01
12.5
2
EPIP I
MeECL
01
20
3
EPIP I
MeECL
02
20
4
EPIP II
MeECL
01
50
5
KHLIEHRIAT
MeECL
01
20
Page 52 of 103
KV
RATIO
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
STEP
%AGE KV
MAKE
TT
NT
PT
….
….
….
….
….
06
….
….
….
….
….
03
….
….
….
….
….
03
….
….
….
….
….
08
….
….
….
….
….
05
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
6
KHLIEHRIAT
MeECL
02
20
7
MAWLAI
MeECL
01
20
8
MAWLAI
MeECL
02
20
9
MAWLAI
MeECL
01
10
10
MAWLAI
MeECL
01
12.5
11
NANGALBIBRA
MeECL
01
10
12
NANGALBIBRA
MeECL
01
12.5
13
NEHU
MeECL
01
20
14
NEHU
MeECL
02
20
15
NEIGRIHMS
MeECL
01
10
16
NEIGRIHMS
MeECL
02
10
17
NONGSTOIN
MeECL
01
12.5
18
UMIUM ST III
MeECL
01
10
19
TURA
MeECL
01
20
20
TURA
MeECL
01
15
21
TURA
MeECL
02
15
22
TURA
MeECL
03
15
23
LUMSHNONG
MeECL
01
10
24
UMTRU
MeECL
01
20
25
BYRNIHAT
MeECL
01
315
400/132
26
BYRNIHAT
MeECL
02
315
400/132
27
NANGALBIBRA
MeECL
01
12.5
132/33
28
NANGALBIBRA
MeECL
02
12.5
132/33
….
….
….
….
….
06
….
….
….
….
….
04
….
….
….
….
….
08
….
….
….
….
….
03
….
….
….
….
….
07
….
….
….
….
….
07
….
….
….
….
….
06
….
….
….
….
….
06
….
….
….
….
….
06
….
….
….
….
….
05
….
….
….
….
….
04
….
….
….
….
….
04
….
….
….
….
….
08
….
….
….
….
….
15
….
….
….
….
….
15
….
….
….
….
….
15
….
….
….
….
….
15
….
….
….
….
….
….
….
….
….
….
….
02
LIST-30: ICT DETAILS OF MIZORAM IN NORTH EASTERN REGION
SL.
NO.
1
2
SUBSTATION
AIZAWL
LUANGMUAL
AIZAWL
LUANGMUAL
AGENCY
ICT
NO.
MVA
MIZORAM
01
12.5
MIZORAM
02
12.5
Page 53 of 103
KV
RATIO
132/33
KV
132/33
KV
STEP
%AGE KV
MAKE
TT
NT
PT
….
….
….
….
….
05
….
….
….
….
….
05
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
AIZAWL
ZUANGTUI
AIZAWL
ZUANGTUI
3
4
MIZORAM
01
12.5
MIZORAM
02
12.5
5
KOLASIB
MIZORAM
01
12.5
6
KOLASIB
MIZORAM
02
12.5
7
LUNGLEI
MIZORAM
01
12.5
8
LUNGLEI
MIZORAM
02
12.5
9
SERCHHIP
MIZORAM
01
12.5
10
SERCHHIP
MIZORAM
02
6.3
11
SAITUAL
MIZORAM
01
6.3
132/33
KV
132/33
KV
132/66
KV
132/66
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
….
….
….
….
….
05
….
….
….
….
….
05
….
….
….
….
….
10
….
….
….
….
….
09
….
….
….
….
….
05
….
….
….
….
….
09
….
….
….
….
….
02
….
….
….
….
….
03
….
….
….
….
….
06
STEP
%AGE KV
PT
LIST-31: ICT DETAILS OF NAGALAND IN NORTH EASTERN REGION
SL.
NO.
SUBSTATION
AGENCY
ICT
NO.
MVA
1
DIMAPUR
NAGALAND
01
20
2
DIMAPUR
NAGALAND
02
20
3
DIMAPUR
NAGALAND
03
20
4
KIPHIRE
NAGALAND
01
6.5
5
KIPHIRE
NAGALAND
02
6.5
6
KIPHIRE
NAGALAND
03
6.5
7
KOHIMA
NAGALAND
01
8
8
KOHIMA
NAGALAND
02
8
9
KOHIMA
NAGALAND
03
8
10
MELURI
NAGALAND
01
5
11
MOKOKCHUNG
NAGALAND
01
12.5
12
MOKOKCHUNG
NAGALAND
02
12.5
13
WOKHA
NAGALAND
01
5
Page 54 of 103
KV
RATIO
132/66
KV
132/66
KV
132/66
KV
132/66
KV
132/66
KV
132/66
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/66
KV
132/66
KV
132/33
KV
MAKE
TT
NT
….
….
….
….
….
05
….
….
….
….
….
05
….
….
….
….
….
03
….
….
….
….
….
04
….
….
….
….
….
04
….
….
….
….
….
04
….
….
….
….
….
03
….
….
….
….
….
03
….
….
….
….
….
03
….
….
….
….
….
01
….
….
….
….
….
04
….
….
….
….
….
04
….
….
….
….
….
03
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
LIST-32: ICT DETAILS OF TSECL IN NORTH EASTERN REGION
SL.
NO.
SUBSTATION
AGENCY
ICT
NO.
MVA
1
AGARTALA
TSECL
01
15
2
AGARTALA
TSECL
01
15
3
AGARTALA
TSECL
02
15
4
AGARTALA
TSECL
03
15
5
AGARTALA
TSECL
04
15
6
AGARTALA
TSECL
01
20
7
AGARTALA
TSECL
02
20
8
AGARTALA
TSECL
01
15
9
AMBASA
TSECL
01
7.5
10
AMBASA
TSECL
02
7.5
11
BARAMURA
TSECL
01
30
12
DHALABIL
TSECL
01
7.5
13
DHARMANAGAR
TSECL
01
7.5
14
DHARMANAGAR
TSECL
02
7.5
15
DHARMANAGAR
TSECL
03
7.5
16
KAILASHOR
TSECL
01
7.5
17
KAMALPUR
TSECL
01
7.5
18
P K BARI
TSECL
01
15
19
P K BARI
TSECL
01
10
20
ROKHIA
TSECL
01
30
21
UDAIPUR
TSECL
01
15
22
UDAIPUR
TSECL
02
10
23
UDAIPUR
TSECL
03
10
24
UDAIPUR
TSECL
04
15
25
UDAIPUR
TSECL
05
10
Page 55 of 103
KV
RATIO
132/66
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/11
KV
132/33
KV
132/33
KV
132/66
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/33
KV
132/11
KV
132/33
KV
132/11
KV
132/66
KV
132/66
KV
132/66
KV
132/66
kV
132/11
kV
66/33
kV
STEP
%AGE KV
MAKE
TT
NT
PT
….
….
….
….
….
09
….
….
….
….
….
13
….
….
….
….
….
13
….
….
….
….
….
13
….
….
….
….
….
13
….
….
….
….
….
13
….
….
….
….
….
13
….
….
….
….
….
13
….
….
….
….
….
08
….
….
….
….
….
08
….
….
….
….
….
05
….
….
….
….
….
04
….
….
….
….
….
07
….
….
….
….
….
07
….
….
….
….
….
07
….
….
….
….
….
08
….
….
….
….
….
08
….
….
….
….
….
05
….
….
….
….
….
05
….
….
….
….
….
05
….
….
….
….
….
05
….
….
….
….
….
05
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
LIST-33: ICT DETAILS OF OTPC IN NORTH EASTERN REGION
SL.
NO.
SUBSTATION
AGENCY
ICT
NO.
MVA
KV
RATIO
MAKE
TT
NT
1
PALLATANA
OTPC
01
125
400/132
kV
BHEL
….
….
STEP
%AGE
KV
….
….
LIST-34:TRANSMISSION/TRANSFOMATION/VAR COMPENSATION
CAPACITY OF NER
TRANSMISSION LINE (CKT KM)
AGENCY
400 KV
220 KV
132 KV
66 KV
POWERGRID
NEEPCO
NETC
STATES
TOTAL
1719.2
NIL
973.14
37
2729.34
1317
NIL
NIL
1639
2956
1988
67
NIL
5702
7757
NIL
NIL
NIL
1809
1809
TRANSFORMATION CAPACITY (MVA)
POWERGRID/NEEPCO/
OTPC/NHPC
STATES
TOTAL
2375/860/125/5 MVA
7285 MVA
10650
REACTIVE COMPENSATION (MVAR)
POWERGRID/NEEPCO/
OTPC
STATES
1318/150/206 MVAR
117 MVAR
CAPACITIVE COMPENSATION – 273 MVAR
Page 56 of 103
PT
….
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
5
HVDC AND VOLTAGE CONTROL
5.1
INTRODUCTION
5.1.1
Basically for transferring power over a long distance or submarine power
transmission, High voltage DC transmission lines (HVDC) are preferred
which transmits power via DC (direct current). They normally consist of
two converter terminals connected by a DC transmission line and in some
applications, multi-terminal HVDC with interconnected DC transmission
lines. Back-to-Back DC and HVDC Light are specific types of HVDC
systems. HVDC Light uses new cable and converter technologies and is
economical at lower power levels than traditional HVDC.
5.2
HVDC CONFIGURATION
5.2.1
Bipolar
In bipolar transmission a pair of conductors is used, each at a high
potential with respect to ground, in opposite polarity. Since these
conductors must be insulated for the full voltage, transmission line cost
is higher than a monopole with a return conductor. However, there are a
number of advantages to bipolar transmission which can make it the
attractive option.
•
•
•
•
Under normal load, negligible earth-current flows, as in the
case of monopolar transmission with a metallic earth-return.
This reduces earth return loss and environmental effects.
When a fault develops in a line, with earth return electrodes
installed at each end of the line, approximately half the rated
power can continue to flow using the earth as a return path,
operating in monopolar mode.
Since for a given total power rating each conductor of a
bipolar line carries only half the current of monopolar lines,
the cost of the second conductor is reduced compared to a
monopolar line of the same rating.
In very adverse terrain, the second conductor may be carried
on an independent set of transmission towers, so that some
power may continue to be transmitted even if one line is
damaged.
Page 57 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
A bipolar system may also be installed with a metallic earth return
conductor. Bipolar systems may carry as much as 3,200 MW at voltages
of +/-600 kV (viz., 2500 MW +/- 500 KV TALCHER – KOLAR HVDC link in
INDIA connecting NEW GRID to SR GRID ) Submarine cable installations
initially commissioned as a monopole may be upgraded with additional
cables and operated as a bipole.
5.2.2
Back to back
A back-to-back station (or B2B for short) is a plant in which both static
inverters and rectifiers are in the same area, usually in the same building.
The length of the direct current line is kept as short as possible. HVDC
back-to-back stations are used for
•
•
•
Coupling of electricity mains of different frequency (as in
INDIA; the interconnection between NEW GRID and SR GRID
through 1000 MW HVDC BHADRAVATI and 1000 MW HVDC
GAZUWAKA)
Coupling two networks of the same nominal frequency but
no fixed phase relationship (viz., HVDC SASARAM, HVDC
VINDHYACHAL).
Different frequency and phase number (for example, as a
replacement for traction current converter plants)
The DC voltage in the intermediate circuit can be selected freely at HVDC
back-to-back stations because of the short conductor length. The DC
voltage is as low as possible, in order to build a small valve hall and to
avoid series connections of valves. For this reason at HVDC back-to-back
stations valves with the highest available current rating are used.
5.2.3
A high voltage direct current (HVDC) link consists of a rectifier and an
inverter. The rectifier side of the HVDC link is equivalent to a load
consuming positive real and reactive power and the inverter side of the
HVDC link as a generator providing positive real power and negative
reactive power (i.e. absorbing positive reactive power).
5.2.4
Thyristor based HVDC converters always consume reactive power when
in operation. A DC line itself does not require reactive power and voltage
drop on the line is only the IR drop where I is the DC current. The
converters at the both ends of the line, however, draw reactive power
from the AC system. The reactive power consumption of the HVDC
Page 58 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
converter/inverter is 50-60 % of the active power converted. It is
independent of the length of the line.
5.2.5
The reactive power requirements of the converter and system have to be
met by providing appropriate reactive power in the station. For those
reason reactive power compensations devices are used together with
reactive power control from the ac side in the form of filter and capacitor
banks.
5.2.6
Both AC and DC harmonics are generated in HVDC converters. AC
harmonics are injected into the AC system and DC harmonics are injected
into the DC line. These harmonics have the following harmful effects:
•
•
•
•
Interference in communication system.
Extra power losses in machines and capacitors connected in
the system.
Some harmonics may produce resonance in AC circuits
resulting in over voltages.
Instability of converter controls.
Basic Components of HVDC Terminal
Converter Xmers
DC Line
Smoothing Reactor
400 kV
AC PLC
DC Filter
DC Filter
DC Filter
DC Filter
AC Filter
AC Filter
Valve Halls
Electrode station
-Thyristors
-Control & Protection
-Firing ckts
-Telecommunication
-Cooling ckt
Control Room
Fig 14. HVDC Fundamental components
5.2.7
Harmonics are normally minimized by using filters. The following types of
filters are used:
•
AC filters.
Page 59 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
•
•
DC filters.
High frequency filters.
AC Filters
AC filters are RLC circuits connected between phase and earth. They
offer low impedance to harmonic frequencies. Thus, AC harmonic
currents are passed to earth. Both tuned and damped filter arrangements
are used. The AC harmonic filters also provide reactive power required
for satisfactory operation of converters and also partly injects reactive
power into the system.
DC Filters
DC filters are similar to AC filters. A DC filter is connected between pole
bus and neutral bus. It diverts DC harmonics to earth and prevents them
from entering DC lines. Such a filter does not supply reactive power as
DC line does not require reactive power.
HIGH FREQUENCY FILTERS
HVDC converters may produce electrical noise in the carrier frequency
band from 20 Khz to 490 Khz. They also generate radio interference noise
in the mega hertz range of frequencies. High frequency (PLC-RI) filters are
used to minimize noise and interference with PLCC. Such filters are
connected between the converter transformer and the station AC bus.
5.3
REACTIVE POWER SOURCE
Reactive power is required for satisfactory operation of converters and
also to boost the AC side voltages. AC harmonic filters which help in
minimizing harmonics also provide reactive power partly. Additional
supply may be obtained from shunt (switched) capacitor banks usually
installed in AC side.
5.4
800 KV HVDC BI-POLE
The first 800kV HVDC bi-pole line in INDIA has been planned from a
pooling substation at Bishwanath Chariali in North-eastern Region to
Agra in Northern region. This is being programmed for commissioning
matching with Subansiri Lower HEP in 2016-17. The transmission line
would be for 6000 MW capacity and HVDC terminal capacity would be
3000 MW between Bishwanath Chariali and Agra. In the second phase, for
transmission of power from hydro projects at Sikkim and Bhutan pooled
at Alipurduar, another 3000 MW terminal modules would be added
between Siliguri and Agra. It is envisaged to take-up the proposed 800kV,
6000MW HVDC bi-pole line from Bishwanath Chariali to Agra under a
scheme titled ”Inter-regional Transmission system for power
export from NER to NR/WR” which is under execution.
Page 60 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
6
FACTS AND VOLTAGE CONTROL
6.1
INTRODUCTION
6.1.1
The demands of lower power losses, faster response to system parameter
change, and higher stability of system have stimulated the development
of the Flexible AC Transmission systems (FACTS). Based on the success
of research in power electronics switching devices and advanced control
technology, FACTS has become the technology of choice in voltage
control, reactive/active power flow control, transient and steady-state
stabilization that improves the operation and functionality of existing
power transmission and distribution system.
6.1.2
The achievement of these studies enlarge the efficiency of the existing
generator units, reduce the overall generation capacity and fuel
consumption, and minimize the operation cost. The power electronicsbased switches in the functional blocks of FACTS can usually be
operated repeatedly and the switching time is a portion of a periodic
cycle, which is much shorter than the conventional mechanical switches.
6.1.3
The advance of semiconductors increases the switching frequency and
voltage-ampere ratings of the solid switches and facilitates the
applications. For example, the switching frequencies of Insulated Gate
Bipolar Transistors (IGBTs) are from 3 kHz to 10 kHz which is several
hundred times the utility frequency of power system (50~60Hz). Gate turnoff thyristors (GTOs) have a switching frequency lower than 1 kHz, but the
voltage and current rating can reach 5-8 kV and 6 kA respectively.
6.2
Static Var Compensator (SVC)
6.2.1
Static Var Compensator is “a shunt-connected static Var generator or
absorber whose output is adjusted to exchange capacitive or inductive
current so as to maintain or control specific parameters of the electrical
power system (typically bus voltage)” .SVC is based on thyristors without
gate turn-off capability.
6.2.2
The operating principal and characteristics of thyristors realize SVC
variable reactive impedance. SVC includes two main components and
their combination: (1) Thyristor-controlled and Thyristor-switched
Reactor (TCR and TSR); and (2) Thyristor-switched capacitor (TSC).
Figure 15 shows the diagram of SVC.
Page 61 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
6.2.3
TCR and TSR are both composed of a shunt-connected reactor controlled
by two parallel, reverse-connected thyristors. TCR is controlled with
proper firing angle input to operate in a continuous manner, while TSR is
controlled without firing angle control which results in a step change in
reactance.
6.2.4
TSC
shares
similar
composition
and
same
operational mode as TSR, but
the reactor is replaced by a
capacitor. The reactance can
only be either fully connected
or fully disconnected zero
due to the characteristic of
capacitor.
With
different
combinations of TCR/TSR,
TSC and fixed capacitors, a
SVC can
meet
various
requirements
to
absorb/supply reactive power
from/to the transmission line.
Fig 15. Static VAR Compensators (SVC):
TCR/TSR, TSC, FC and Mechanically Switched
Resistor
6.3
Converter-based Compensator
6.3.1
Static Synchronous Compensator (STATCOM) is one of the key
Converter-based Compensators which are usually based on the voltage
source inverter (VSI) or
current source inverter (CSI),
as shown in Figure 16 (a).
Unlike
SVC,
STATCOM
controls the output current
independently of the AC
system voltage, while the DC
side voltage is automatically
maintained to serve as a
voltage
source.
Mostly,
STATCOM is designed based
on
the
VSI
(VOLTAGE
SOURCE INVERTER).
Fig 16. STATCOM topologies: (a) STATCOM
based on VSI and CSI (b) STATCOM with storage
Page 62 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
6.3.2
Compared with SVC, the topology of a STATCOM is more complicated.
The switching device of a VSI is usually a gate turn-off device paralleled
by a reverse diode; this function endows the VSI advanced controllability.
6.3.3
Various combinations of the switching devices and appropriate topology
make it possible for a STATCOM to vary the AC output voltage in both
magnitude and phase. Also, the combination of STATCOM with a different
storage device or power source (as shown in Figure 16b) endows the
STATCOM the ability to control the real power output.
6.3.4
STATCOM has much better dynamic performance than conventional
reactive power compensators like SVC. The gate turn-off ability shortens
the dynamic response time from several utility period cycles to a portion
of a period cycle. STATCOM is also much faster in improving the
transient response than a SVC. This advantage also brings higher
reliability and larger operating range.
6.4
Series-connected controllers
6.4.1
As shunt-connected controllers, seriescontrollers can also be
divided into
converter type.
6.4.2
The
former
includes
Thyristor-Switched
Series
Capacitor
(TSSC),
Thyristor-Controlled
Series
Capacitor (TCSC), ThyristorSwitched
Series Reactor,
and
Thyristor-Controlled
Series Reactor.
6.4.3
The latter, based on VSI, is
usually in the Compensator
(SSSC). The composition and
operation of different types are
similar to the operation of the
shunt connected peers. Figure
shows the diagrams of various
series-connected controllers.
connected
either impedance
FACTS
type or
Fig 17. Series-connected FACTS controllers:
(a) TCSR and TSSR; (b) TSSC; (c) SSSC
Page 63 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
7
GENERATOR REACTIVE POWER AND
VOLTAGE CONTROL
7.1
INTRODUCTION
7.1.2
An electric-power generator’s primary function is to convert fuel (or other
energy resource) into electric power. Almost all generators also have
considerable control over their terminal voltage and reactive-power
output.
7.1.3
The ability of a generator
to
provide
reactive
support depends on its
real-power
production
which is represented in
the form of generator
capability curve or D curve. Figure 18 shows
the combined limits on
real
and
reactive
production for a typical
generator.
Like
most
electric
equipment,
generators are limited by
their
current-carrying
capability.
Near
rated
voltage, this capability
becomes an MVA limit for
the armature of the
generator rather than a
MW limitation, shown as
the armature heating limit
in the Figure.
7.1.4
Fig 18. D-Curve of a typical Generator
Production of reactive power involves increasing the magnetic field to
raise the generator’s terminal voltage. Increasing the magnetic field
requires increasing the current in the rotating field winding. This too is
current limited, resulting in the field-heating limit shown in the figure.
Absorption of reactive power is limited by the magnetic-flux pattern in the
stator, which results in excessive heating of the stator-end iron, the coreend heating limit. The synchronizing torque is also reduced when
absorbing large amounts of reactive power, which can also limit
Page 64 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
generator capability to reduce the chance of losing synchronism with the
system.
7.1.5
The generator prime mover (e.g., the steam turbine) is usually designed
with less capacity than the electric generator, resulting in the primemover limit in Fig. 18. The designers recognize that the generator will be
producing reactive power and supporting system voltage most of the
time. Providing a prime mover capable of delivering all the mechanical
power the generator can convert to electricity when it is neither
producing nor absorbing reactive power would result in underutilization
of the prime mover.
7.1.6
To produce or absorb additional VARs beyond these limits would require
a reduction in the real-power output of the unit. Capacitors supply
reactive power and have leading power factors, while inductors consume
reactive power and have lagging power factors. The convention for
generators is the reverse. When the generator is supplying reactive
power, it has a lagging power factor and its mode of operation is referred
to as overexcited. When a generator consumes reactive power, it has a
leading power factor region and is under excited.
7.1.7
Control over the reactive output and the terminal voltage of the generator
is provided by adjusting the DC current in the generator’s rotating field.
Control can be automatic, continuous, and fast. The inherent
characteristics of the generator help maintain system voltage.
7.1.8
At any given field setting, the generator has a specific terminal voltage it
is attempting to hold. If the system voltage declines, the generator will
inject reactive power into the power system, tending to raise system
voltage. If the system voltage rises, the reactive output of the generator
will drop, and ultimately reactive power will flow into the generator,
tending to lower system voltage.
7.1.9
The voltage regulator will accentuate this behavior by driving the field
current in the appropriate direction to obtain the desired system voltage.
Because most of the reactive limits are thermal limits associated with
large pieces of equipment, significant short-term extra reactive-power
capability usually exists. Power-system stabilizers also control generator
field current and reactive-power output in response to oscillations on the
power system. This function is a part of the network-stability ancillary
service.
Page 65 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
7.2
SYNCHRONOUS CONDENSERS
7.2.1
Every synchronous machine (motor or generator) has the reactive power
capability. Synchronous motors are occasionally used to provide voltage
support to the power system as they provide mechanical power to their
load. Some combustion turbines and hydro units are designed to allow
the generator to operate without its mechanical power source simply to
provide the reactive-power capability to the power system when the real
power generation is unavailable or not needed.
7.2.2
Synchronous machines that are designed exclusively to provide reactive
support are called synchronous condensers. Synchronous condensers
have all of the response speed and controllability advantages of
generators without the need to construct the rest of the power plant (e.g.,
fuel-handling equipment and boilers). Because they are rotating machines
with moving parts and auxiliary systems, they may require significantly
more maintenance than static alternatives. They also consume real power
equal to about 3% of the machine’s reactive-power rating. That is, a 50MVAR synchronous condenser requires about 1.5 MW of real power.
7.2.3
As per planning philosophy and general guidelines in the Manual on
Transmission planning criteria issued by CEA (MOP, India), Thermal /
Nuclear Generating Units shall normally not run at leading power factor.
However for the purpose of charging unit may be allowed to operate at
leading power factor as per the respective capability curve.
7.2.4
Generator capability may depend significantly on the type and amount of
cooling. This is particularly true of hydrogen cooled generators where
cooling gas pressure affects both the real and reactive power capability
Table 5. List of units in NER required to be normally operated with free governor action
and AVR in service.
SL. NO.
STATION
UTILITY
UNIT NO.
UNIT
CAPACITY
(MW)
TYPE
1
KOPILI HEP
NEEPCO
1,2,3 & 4*
50
HYDEL
2
RANGANADI
HEP
NEEPCO
1,2 & 3
135
HYDEL
*Units running in 132 KV pocket is exempt from FGMO.
Page 66 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
1.
LTPS UNIT 5, 6 & 7 CAPABILITY CURVE
Page 67 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
2.
NTPS UNIT 1, 2 & 3 CAPABILITY CURVE
Page 68 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
3.
NTPS UNIT 4 CAPABILITY CURVE
Page 69 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
4.
NTPS UNIT 6 CAPABILITY CURVE
Page 70 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
5.
LTPS CAPABILITY CURVE
Page 71 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
6.
NTPS CAPABILITY CURVE
Page 72 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
7.
UMIUM ST I CAPABILITY CURVE
Page 73 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
8.
UMIUM STAGE II CAPABILITY CURVE
Page 74 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
9.
UMIUM STAGE III CAPABILITY CURVE
Page 75 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
10.
UMIUM STAGE IV CAPABILITY CURVE
Page 76 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
11.
AGBPP UNIT 5, 6, 7, 8 & 9 CAPABILITY CURVE
Page 77 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
12.
AGBPP UNIT 1, 2, 3 & 4 CAPABILITY CURVE
Page 78 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
13.
AGTPP CAPABILITY CURVE
Page 79 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
14.
DOYANG HEP UNIT 1 CAPABILITY CURVE
Page 80 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
15.
KHANDONG HEP UNIT 2 CAPABILITY CURVE
Page 81 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
16.
KOPILI HEP UNIT 1 CAPABILITY CURVE
Page 82 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
17.
KOPILI HEP UNIT 2 CAPABILITY CURVE
Page 83 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
18.
KOPILI HEP ST II CAPABILITY CURVE
Page 84 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
19.
RANGANADI HEP CAPABILITY CURVE
Page 85 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
20.
LOKTAK HEP CAPABILITY CURVE
Page 86 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
21.
ROKHIA UNIT 3, 4 & 6 CAPABILITY CURVE
Page 87 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
22.
ROKHIA & BARAMURA CAPABILITY CURVE
Page 88 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
23.
OTPC PALATANA GTG CAPABILITY CURVE
Page 89 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
24.
OTPC PALATANA STG CAPABILITY CURVE
Page 90 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
8
CONCLUSION
8.1
Generators, synchronous condensers, SVCs, and STATCOMs all provide
fast, continuously controllable reactive support and voltage control. LTC
transformers provide nearly continuous voltage control but they are slow
because the transformer moves reactive power from one bus to another,
the control gained at one bus is at the expense of the other. Capacitors
and inductors are not variable and offer control only in large steps.
8.2
An unfortunate characteristic of capacitors and capacitor-based SVCs is
that output drops dramatically when voltage is low and support is needed
most. The output of a capacitor, and the capacity of an SVC, is
proportional to the square of the terminal voltage. STATCOMs provide
more support under low-voltage conditions than capacitors or SVCs do
because they are current-limited devices and their output drops linearly
with voltage.
8.3
The output of rotating machinery (i.e., generators and synchronous
condensers) rises with dropping voltage unless the field current is
actively reduced. Generators and synchronous condensers generally
have additional emergency capacity that can be used for a limited time.
Voltage-control characteristics favour the use of generators and
synchronous condensers. Costs, on the other hand, favor capacitors.
8.4
Generators have extremely high capital costs because they are designed
to produce real power, not reactive power. Even the incremental cost of
obtaining reactive support from generators is high, although it is difficult
to unambiguously separate reactive-power costs from real-power costs.
Operating costs for generators are high as well because they involve realpower losses. Finally, because generators have other uses, they
experience opportunity costs when called upon to simultaneously
provide high levels of both reactive and real power.
8.5
Synchronous condensers have the same costs as generators but,
because they are built solely to provide reactive support, their capital
costs do not include the prime mover or the balance of plant and they
incur no opportunity costs. SVCs and STATCOMs are high-cost devices,
as well, although their operating costs are lower than those for
synchronous condensers and generators.
Page 91 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
9
SUMMARY
9.1
The process of controlling voltages and managing reactive power on
interconnected transmission systems is well understood from a technical
perspective. Three objectives dominate reactive-power management.
First, maintain adequate voltages throughout the transmission system
under current and contingency conditions. Second, minimize congestion
of real-power flows. Third, minimize real-power losses.
9.2
This process must be performed centrally because it requires a
comprehensive view of the power system to assure that control is
coordinated. System operators and planners use sophisticated computer
models to design and operate the power system reliably and
economically. Central control by rule works well but may not be the most
technically and economically effective means.
9.3
The economic impact of control actions can be quite different in a
restructured/regulated industry than for vertically integrated utilities.
While it may be sufficient to measure only the response of the system in
aggregate for a vertically integrated utility, determining individual
generator performance will be critical in a competitive environment.
9.4
While it reduces or eliminates opportunity costs by providing sufficient
capacity, it can waste capital. When an investor is considering
construction of new generation, the amount of reactive capability that the
generator can provide without curtailing real-power production should
depend on system requirements and the economics of alternatives, not
on a fixed rule.
9.5
The introduction of advanced devices, such as STATCOMs and SVCs,
further complicates the split between transmission- and generation based
voltage control. The fast response of these devices often allows them to
substitute for generation-based voltage control. But their high capital
costs limit their use. If these devices could participate in a competitive
voltage-control market, efficient investment would be encouraged.
9.6
In areas with high concentrations of generation, sufficient interaction
among generators is likely to allow operation of a competitive market. In
other locations, introduction of a small amount of controllable reactive
support on the transmission system might enable market provision of the
bulk of the reactive support. In other locations, existing generation would
be able to exercise market power and would continue to require economic
regulation for this service.
Page 92 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
9.7
A determination of the extent of each type within each region would be a
useful contribution to restructuring. System planners and operators need
to work closely together during the design of new facilities and
modification of existing facilities. Planners must design adequate reactive
support into the system to provide satisfactory voltage profiles during
normal and contingency operating conditions. Of particular importance is
sufficient dynamic support, such as the reactive output of generators,
which can supply additional reactive power during contingencies.
9.8
System operators must have sufficient metering and analytical tools to be
able to tell when and if the operational reactive resources are sufficient.
Operators must remain cognizant of any equipment outages or problems
that could reduce the system’s static or dynamic reactive support below
desirable levels. Ensuring that sufficient reactive resources are available
in the grid to control voltages may be increasingly difficult because of the
disintegration of the electricity industry.
9.9
Traditional vertically integrated utilities contained, within the same entity,
generator reactive resources, transmission reactive resources, and the
control center that determined what resources were needed when.
Presently, these resources and functions are placed within three different
entities. In addition, these entities have different, perhaps conflicting,
goals. In particular, the owners of generating resources will be driven, in
competitive generation markets, to maximize the earnings from their
resources. They will not be willing to sacrifice revenues from the sale of
real power to produce reactive power unless appropriately compensated.
9.10
Similarly, transmission owners will want to be sure that any costs they
incur to expand the reactive capabilities on their system (e.g., additional
capacitors) will be reflected fully in the transmission rates that they are
allowed to charge.
9.11
Failure to appropriately compensate those entities that provide voltagecontrol services could lead to serious reliability problems and severe
constraints on inter regional links and other congested areas as TTC
(Total Transfer Capability) has a voltage limit function as a baggage with
it which is directly linked to var compensation. With dynamic ATC’s
(Available Transfer capability), Var compensation if not seriously thought
of may have serious commercial implications in time to come due to the
amount of bulk power trading happening across the country in today’s
context.
Page 93 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
10
10.1
Statutory Provisions for Reactive
Management and voltage Control
Power
Provision in the Central Electricity Authority (Technical
Standard for connectivity to the grid) Regulations 2007 [8]:
Extracts from this standard is as reproduced below for ready reference.
Part II : Grid Connectivity Standards applicable to the Generating Units
The units at a generating station proposed to be connected to the grid
shall comply with the following requirements besides the general
connectivity conditions given in the regulations and general requirements
given in part-I of the Schedule:1.
New Generating Units
Hydro generating units having rated capacity of 50 MW and
above shall be capable of operation in synchronous
condenser mode, where ever feasible.
2.
Existing Units
For thermal generating unit having rated capacity of 200
MW and above and hydro units having rated capacity of 100
MW and above, the following facilities would be provided at
the time of renovation and modernization.
(1)
Every generating unit shall have Automatic Voltage
Regulator. Generators having rated capacity of 100
MW and above shall have Automatic Voltage Regulator
with two separate with two separate channels having
independent inputs and automatic changeover.
10.2
Provision in The Indian Electricity Grid Code (IEGC),
2010:
10.2.1
As per sec 3.5 of IEGC planning criterion general policy
(a)
The planning criterion are based on the security philosophy
on which the ISTS has been planned. The security
philosophy may be as per the Transmission Planning
Criteria and other guidelines as given by CEA. The general
policy shall be as detailed below:
i) As a general rule, the ISTS shall be capable of
withstanding and be secured against the following
contingency outages
Page 94 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
a. without necessitating load shedding or rescheduling
of generation during Steady State Operation:
Outage of a 132 kV D/C line or,
Outage of a 220 kV D/C line or,
Outage of a 400 kV S/C line or,
Outage
of
single
Interconnecting
Transformer, or
Outage of one pole of HVDC Bipole line, or
one pole of HVDC back to back Station or
Outage of 765 kV S/C line.
b. without necessitating load shedding but could be
with rescheduling of generation during steady
state operationOutage of a 400 kV S/C line with TCSC, or
Outage of a 400kV D/C line, or
Outage of both pole of HVDC Bipole line or
both poles of HVDC back to back Station or
Outage of a 765kV S/C line with series
compensation.
ii) The above contingencies shall be considered assuming
a pre-contingency system depletion (Planned outage) of
another 220 kV D/C line or 400 kV S/C line in another
corridor and not emanating from the same substation.
The planning study would assume that all the
Generating Units may operate within their reactive
capability curves and the network voltage profile shall
also be maintained within voltage limits specified
(e)
10.2.2
CTU shall carry out planning studies for Reactive Power
compensation of ISTS including reactive power
compensation requirement at the generator’s /bulk
consumer’s switchyard and for connectivity of new
generator/ bulk consumer to the ISTS in accordance with
Central Electricity Regulatory Commission ( Grant of
Connectivity, Long-term Access and Medium-term Open
Access in inter-state Transmission and related matters)
Regulations, 2009.
As per Sec 4.6.1 of IEGC, Important Technical Requirements for
Connectivity to the Grid:
Reactive Power Compensation
a)
Reactive Power compensation and/or other facilities, shall
be provided by STUs, and Users connected to ISTS as far
as possible in the low voltage systems close to the load
Page 95 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
points thereby avoiding the need for exchange of Reactive
Power to/from ISTS and to maintain ISTS voltage within the
specified range.
b)
10.2.3
The person already connected to the grid shall also provide
additional reactive compensation as per the quantum and
time frame decided by respective RPC in consultation with
RLDC. The Users and STUs shall provide information to
RPC and RLDC regarding the installation and healthiness
of the reactive compensation equipment on regular basis.
RPC shall regularly monitor the status in this regard.
In chapter 5 of IEGC operating code for regional grids:
5.2(k) All generating units shall normally have their automatic
voltage regulators (AVRs) in operation. In particular, if a
generating unit of over fifty (50) MW size is required to be
operated without its AVR in service, the RLDC shall be
immediately intimated about the reason and duration, and
its permission obtained. Power System Stabilizers (PSS) in
AVRs of generating units (wherever provided), shall be got
properly tuned by the respective generating unit owner as
per a plan prepared for the purpose by the CTU/RPC from
time to time. CTU /RPC will be allowed to carry out
checking of PSS and further tuning it, wherever considered
necessary.
5.2(o) All Users, STU/SLDC , CTU/RLDC and NLDC, shall also
facilitate identification, installation and commissioning of
System Protection Schemes (SPS) (including inter-tripping
and run-back) in the power system to operate the
transmission system closer to their limits and to protect
against situations such as voltage collapse and cascade
tripping, tripping of important corridors/flow-gates etc..
Such schemes would be finalized by the concerned RPC
forum, and shall always be kept in service. If any SPS is to
be taken out of service, permission of RLDC shall be
obtained indicating reason and duration of anticipated
outage from service.
5.2(s) All Users, RLDC, SLDC STUs , CTU and NLDC shall take all
possible measures to ensure that the grid voltage always
remains within the following operating range.
Page 96 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
Voltage – (KV rms)
Nominal
Maximum
Minimum
765
800
728
400
420
380
220
245
198
132
145
122
110
121
99
66
72
60
33
36
30
Table 6: IEGC operating voltage range
5.2(u) (ii) During the wind generator start-up, the wind generator
shall ensure that the reactive power drawl (inrush
currents incase of induction generators) shall not affect
the grid performance.
10.2.4
In chapter 6 of IEGC Section-6.6 Reactive Power & Voltage Control:
1.
Reactive power compensation should ideally be provided
locally, by generating reactive power as close to the
reactive power consumption as possible. The Regional
Entities except Generating Stations are therefore expected
to provide local VAr compensation/generation such that
they do not draw VArs from the EHV grid, particularly under
low-voltage condition. To discourage VAr drawals by
Regional Entities except Generating Stations, VAr
exchanges with ISTS shall be priced as follows:
-
The Regional Entity except Generating Stations pays
for VAr drawal when voltage at the metering point is
below 97%
-
The Regional Entity except Generating Stations gets
paid for VAr return when voltage is below 97%
-
The Regional Entity except Generating Stations gets
paid for VAr drawal when voltage is above103%
Page 97 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
The Regional Entity except Generating Stations pays for
VAr return when voltage is above 103% Provided that there
shall be no charge/payment for VAr drawal/return by a
regional Entity except Generating Stations on its own line
emanating directly from an ISGS.
2.
The charge for VArh shall be at the rate of 10 paise/kVArh
w.e.f. 1.4.2010, and this will be applicable between the
Regional Entity, except Generating Stations, and the
regional pool account for VAr interchanges. This rate shall
be escalated at 0.5paise/kVArh per year thereafter, unless
otherwise revised by the Commission.
3
Notwithstanding the above, RLDC may direct a Regional
Entity except Generating Stations to curtail its VAr
drawal/injection in case the security of grid or safety of any
equipment is endangered.
4.
In general, the Regional Entities except Generating Stations
shall endeavor to minimize the VAr drawal at an
interchange point when the voltage at that point is below
95% of rated, and shall not return VAr when the voltage is
above 105%. ICT taps at the respective drawal points may
be changed to control the VAr interchange as per a
Regional Entity except Generating Stations’s request to the
RLDC, but only at reasonable intervals.
5.
Switching in/out of all 400 kV bus and line Reactors
throughout the grid shall be carried out as per instructions
of RLDC. Tap changing on all 400/220 kV ICTs shall also be
done as per RLDCs instructions only.
6.
The ISGS and other generating stations connected to
regional grid shall generate/absorb reactive power as per
instructions of RLDC, within capability limits of the
respective generating units, that is without sacrificing on
the active generation required at that time. No payments
shall be made to the generating companies for such VAr
generation/absorption.
7.
VAr exchange directly between two Regional Entities
except Generating Stations on the interconnecting lines
owned by them (singly or jointly) generally address or
cause a local voltage problem, and generally do not have
an impact on the voltage profile of the regional grid.
Accordingly, the management/control and commercial
handling of the VAr exchanges on such lines shall be as
per following provisions, on case-by-case basis:
Page 98 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
i) The two concerned Regional Entities except Generating
Stations may mutually agree not to have any
charge/payment for VAr exchanges between them on an
interconnecting line.
ii) The two concerned Regional Entities except Generating
Stations may mutually agree to adopt a payment
rate/scheme for VAr exchanges between them identical
to or at variance from that specified by CERC for VAr
exchanges with ISTS. If the agreed scheme requires any
additional metering, the same shall be arranged by the
concerned Beneficiaries.
iii) In case of a disagreement between the concerned
Regional Entities except Generating Stations (e.g. one
party wanting to have the charge/payment for VAr
exchanges, and the other party refusing to have the
scheme), the scheme as specified in Annexure-2 shall
be applied. The per kVArh rate shall be as specified by
CERC for VAr exchanges with ISTS.
iv) The computation and payments for such VAr exchanges
shall be effected as mutually agreed between the two
Beneficiaries.
10.3
THE AEGCL GAZETTE, EXTRAORDINARY, FEBRUARY
10, 2005
10.3.1
IN CHAPTER 9: FREQUENCY AND VOLTAGE MANAGEMENT
10.3.1.1 (9.1) Introduction
(a) This section describes the method by which all Users of the
State Grid shall cooperate with SLDC in contributing towards
effective control of the system frequency and managing the
grid voltage.
(b) State Grid normally operates in synchronism with the NorthEastern Regional Grid and NERLDC has the overall
responsibility of the integrated operation of the NorthEastern Regional Power System. The constituents of the
Region are required to follow the instructions of NERLDC for
the backing down generation, regulating loads, MVAR drawal
etc. to maintain the system frequency and the grid voltage.
Page 99 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
(c) SLDC shall instruct SSGS to regulate Generation/Export and
hold reserves of active and reactive power within their
respective declared parameters. SLDC shall also regulate the
load as may be necessary to meet the objective.
(d) System voltages levels can be affected by Regional
operation. The SLDC shall optimise voltage management by
adjusting transformer taps to the extent available and
switching of circuits/ capacitors/ reactors and other
operational steps. SLDC will instruct generating stations to
regulate MVAr generation within their declared parameters.
SLDC shall also instruct Distribution Licensees to regulate
demand, if necessary.
10.3.1.2 (9.2) Objective
The objectives of this section are as follows:
(a) To define the responsibilities of all Users in contributing to
frequency and voltage management.
(b) To define the actions required to enable SLDC to maintain
System voltages and frequency within acceptable levels in
accordance Planning and Security Standards of IEGC.
10.3.1.3 (9.3) Frequency Management
The rated frequency of the system shall be 50 Hz and shall normally
be regulated within the limits prescribed in IEGC Clause 4.6(b). As a
constituent of North-Eastern Region, the SLDC shall make all
possible efforts to ensure that grid frequency remain within normal
band of 49.5 – 50.2Hz (Presently IEGC band is 49.7-50.2 Hz).
10.3.1.4 (9.4) Basic philosophy of control
Frequency being essentially the index of load-generation balance
conditions of the system, matching of available generation with load,
is the only option for maintaining frequency within the desired limits.
Basically, two situations arise, viz., a surplus situation and a deficit
situation. The automatic mechanisms available for adjustment of
load/generation are (i) Free governor action; (ii) Maintenance of
spinning reserves and (iii) Under-frequency relay actuated shedding.
These measures are essential elements of system security. SLDC
shall ensure that Users of the State Grid comply with provisions of
clause 6.2 of the IEGC so far as they apply to them. The SLDC in
coordination with Users shall exercise the manual mechanism for
frequency control under following situations:
10.3.1.5 (9.5) Falling frequency:
Page 100 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
Under falling frequency conditions, SLDC shall take appropriate
action to issue instructions, in coordination with NERLDC to arrest
the falling frequency and restore it to be within permissible range.
Such instructions may include dispatch instruction to SSGS and/or
instruction to Distribution Licensees and Open access customers to
reduce load demand by appropriate manual and/or automatic load
shedding.
10.3.1.6 (9.6) Rising Frequency
Under rising frequency conditions, SLDC shall take appropriate
action to issue instructions to SSGS in co-ordination with NERLDC,
to arrest the rising frequency and restore frequency within
permissible range through backing down hydel generation and
thermal generation to the level not requiring oil support. SLDC shall
also issue instructions to Distribution Licensees and Open access
customers in coordination with NERLDC to lift Load shedding (if
exists) in order to take additional load.
10.3.1.7 (9.7) Responsibilities
SLDC shall monitor actual Drawal against scheduled Drawal and
regulate internal generation/demand to maintain this schedule. SLDC
shall also monitor reactive power drawal and availability of capacitor
banks. Generating Stations within AEGCL shall follow the dispatch
instructions issued by SLDC.Distribution Licensees and Open
access customers shall co-operate with SLDC in managing load &
reactive power drawal on instruction from SLDC as required.
10.3.1.8 (9.8) Voltage Management
(a) Users using the Intra State transmission system shall make
all possible efforts to ensure that the grid voltage always
remains within the limits specified in IEGC at clause 6.2(q)
and produced below:
Nominal
Maximum
Minimum
400
420
380
220
245
198
132
145
122
(b) AEGCL Gridco and/or SLDC shall carry out load flow studies
based on operational data from time to time to predict where
voltage problems may be encountered and to identify
Page 101 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
appropriate measures to ensure that voltages remain within
the defined limits. On the basis of these studies SLDC shall
instruct SSGS to maintain specified voltage level at
interconnecting points. SLDC and AEGCL Gridco shall coordinate with the Distribution Licensees to determine voltage
level at the interconnection points. SLDC shall continuously
monitor 400/220/132kV voltage levels at strategic substations to control System voltages.
(c)
SLDC in close coordination with NERLDC shall take
appropriate measures to control System voltages which may
include but not be limited to transformer tap changing,
capacitor / reactor switching including capacitor switching
by Distribution Licensees at 33 kV substations, operation of
Hydro unit as synchronous condenser and use of MVAr
reserves with SSGS within technical limits agreed to between
AEGCL Gridco and Generators. Generators shall inform
SLDC of their reactive reserve capability promptly on
request.
(d) APGCL and IPPs shall make available to SLDC the up to date
capability curves for all Generating Units, as detailed in
Chapter 5.indicating any restrictions, to allow accurate
system studies and effective operation of the Intra State
transmission system. CPPs shall similarly furnish the net
reactive capability that will be available for Export to / Import
from Intra State transmission system.
(e)
Distribution Licensees and Open access customers shall
participate in voltage management by providing Local VAR
compensation (as far as possible in low voltage system close
to load points) such that they do not depend upon EHV grid
for reactive support.
10.3.1.9 (9.9) General
Close co-ordination between Users and SLDC, AEGCL Gridco and
NERLDC shall exist at all times for the purposes of effective
frequency and voltage management.
Page 102 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
11.
Bibliography:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
Best practice manual of transformer for BEE and IREDA by Devki energy
consultancy pvt. ltd.
NERPC progress report August, 2010.
Document on MeSEB capacity building and training document
Manual on Transmission Planning Criteria, CEA, Govt. of India, June 1994
Indian Electricity Grid Code, CERC, India, 2010
The Central Electricity Authority (Technical Standard for connectivity to the grid)
Regulations 2007.
Operation procedure for NER January 2010.
Document on Metering code for AEGCL grid.
Principles of efficient and reliable reactive power supply and consumption, staff
report, FERC, Docket No. AD05-1-000, February 4, 2005
th
th
Proceedings of workshop on grid security & management 28 and 29 April,
2008 Bangalore.
Extra High Voltage AC transmission Engineering – R D Begamudre.
Electrical Engineering Handbook – SIEMENS.
C. W. Taylor, “Power System Voltage Stability”, McGraw-Hill, 1994.
THE AEGCL GAZETTE, EXTRAORDINARY, FEBRUARY 10, 2005
Page 103 of 103
REACTIVE POWER MANAGEMENT AND VOLTAGE CONTROL IN NORTH EASTERN REGION
POWER SYSTEM OPERATION CORPORATION LIMITED
(A wholly owned subsidiary of Powergrid)
(A GOVT. OF INDIA UNDERTAKING)
NORTH EASTERN REGIONAL LOAD DESPATCH CENTRE
DONGTIEH-LOWER NONGRAH,
LAPALANG,
SHILLONG – 793 006
Page 104 of 103
MEGHALAYA