Madhya Pradesh Energy Efficiency Improvement Investment Program
(RRP IND 43467)
FEEDER SEPARATION AND HIGH VOLTAGE DISTRIBUTION SYSTEMS
A.
Feeder Separation
1.
A power supply line to a rural area begins at a 33 kV/11 kV substation (a primary
substation), where incoming power at 33 kV is stepped down to 11 kV (Figure 1). A threephase, three-wire distribution line operating at 11 kV, known as a feeder, begins at the
primary substation, and traverses the rural areas through villages and agricultural areas,
serving a mixed customer base of agriculture, households and small businesses. The total
length of this 11 kV feeder may exceed 10 km, and if feasible, would terminate when it
meets another 11 kV feeder from another primary substation. Otherwise, the 11 kV feeder
would terminate at a location beyond which there are no customers. Along each such 11 kV
feeder, there are 11 kV/433 V distribution substations at suitable locations, to step down the
voltage from 11 kV to the nominal 400 V, three-phase, four-wire supply required for
agricultural water pumps and other industrial equipment, if any. Single-phase, two-wire
supply from the same line provides the service for household customers and small
businesses. Agricultural pumps are scattered in vast areas of farmland, while household and
small businesses are located in the villages.
Figure 1: Present arrangement of feeders in rural areas
Primary
Substation
DS2
Mixed customers
P, H, B
11 kV
feeder
33 kV line
from EHV
substation
MF1
X
DL1
DL2 DL3
Mixed customers
P, H, B
HH
MF2
DS3
HH
HH
HH
P
HH
11 kV feeder, to another
group of villages and
farms
HH
Mixed
customers
P, H, B
HH
P
B
HH
P
P
HH
P
B
P
HH
P
Bare conductor
distribution lines
Normally
open
switch
11 kV
feeder
DS1
33 kV/11 kV
transformer
X
11 kV
feeder
P
DS4
Another 11 kV
feeder from a
different primary
substation
Mixed
customers
P, H, B
MF: Mixed 11 kVFeeder
DS: Distribution Substatioin
DL: Distribution line
P
Agricultural Water Pump
P
HH
B
Household customer
Small business
Note: The layout does not refer to any particular area or village. Distances are
not to scale and they have been shrunk or exaggerated to elaborate the concept.
Source: Project preparatory technical assistance consultants.
2.
Electricity supply to agricultural water pumping for metered customers is provided on
the basis of a charge per kilowatthour (KWh). In DISCOM-C (Table 1) in 2009-10, 58% of
pumps were un-metered, and the estimated sales to such un-metered pumps (on the basis
of approved consumption) was 25.4% of total sales of the DISCOM. In DISCOM-E, 69% of
pumps were un-metered and estimated sales to such pumps were 16% of the total sales of
teh DISCOM. Thus, a significant percentage services to water pumps is un-metered, and for
such connections, the amount of electrical energy allowed to be used per month in each
season is determined on the basis of the approved capacity of pump(s) for each customer.
Such approved use from un-metered connections is stated in the tariff schedule approved by
the Madhya Pradesh Electricity Regulatory Commission (MPERC). However, there is no
effective mechanism to monitor excessive use of electricity for water pumping, off unmetered service connections. For example, the approved consumption of an un-metered
2
three-phase 10 hp water pump for agriculture in the month of March 2011 is 1500 kWh. The
electricity input to a 10 hp pump is about 9 kW. If the pump is used for 8 hours per day, its
consumption is 9 x 8 x 30 = 2160 kWh per month. The approved 1500 kWh per month is
therefore adequate to operate the pump only for about 5.5 hours per day. Any use above the
approved use is counted as commercial losses. Hence, DISCOMs are compelled to ration
the electricity supply to rural areas.
Table 1: Metered and un-metered pumps in DISCOM-C, and estimated sales 2009-10
Agricultural pumps
Metered general
Metered temporary
Metered free
Un-metered general
Un-metered temporary
Un-metered free
Total
Customers
100,352
596
196
178,803
34,989
4,581
319,517
Total DISCOM-C
2,209,964
Source: DISCOM-C estimates.
% of
pumps
31.4%
0.2%
0.1%
56.0%
11.0%
1.4%
100.0%
25.0
8.9
0.2
1,390.5
349.0
30.7
1,804.4
As a share of
Sales to
agri.
Total sales of
pumps
DISCOM
1.4%
0.4%
0.5%
0.1%
0.0%
0.0%
77.1%
20.0%
19.3%
5.0%
1.7%
0.4%
100.0%
26.0%
6,942.4
100.0%
Sales (GWh) in
2009-10
3.
Presently, the 11 kV feeder is switched-off from the primary substation end for
several hours each day, when DISCOMs require to ration electricity supply to agricultural
pumps. With a mixed customer base on the feeder, villages served by this 11 kV feeder,
their households and businesses too suffer with no electricity supply during this period. In
general, the feeder is switched-on for a maximum of eight hours each day, depending on the
assessed pumping requirements, based on the season and weather. Thus, power supply is
not available to any customer in rural areas for about 16 hours of the day.
4.
In some areas, to implement rationing, DISCOMs have adopted the practice of
switching off one line of the three-wire 11 kV feeder at the point of its origin (the primary
substation), which technically prevents three-phase water pumps being operated by
agricultural customers served by the feeder. Single-phase, two-wire services will remain live,
to serve households and small businesses. However, this practice causes the 11 kV feeder
and the distribution substations along the feeder to be operated in an unbalanced mode,
resulting in poor voltage of supply to households and frequent damages to distribution
transformers. The GOMP has made it a requirement to supply three-wire supply both type
od customers since 2009.
5.
Therefore, GOMP is in the process of implementing a “Feeder Separation Program”.
Please see Figure 2. Once the program is implemented, to serve the areas presently served
by a single 11 kV feeder, with mixed village and agricultural customers, there will be two
such feeders. (i) The existing 11 kV mixed feeder (MF1), in most cases1, will be rehabilitated
and designated as the agricultural feeder (AF1), and it will serve only the distribution
substations serving water pumps. The AF1 will be switched on and off direct from the
primary substation, based on the approved duration allowed for water pumping each day, on
the basis of seasonal water requirements and daily weather. (ii) a new 11 kV feeder,
designated as the village feeder (VF1), will commence from the primary substation and
traverse the rural areas, serving only the villages. VF1 will remain live throughout the day.
Distribution substations located along the present 11 kV mixed feeder will be rehabilitated
and re-located if required, to be closer to their intended customers, ie either the village or the
1
In some cases, depending on the layout of the existing 11 kV feeder and the farmlands/villages, the
existing feeder may be designated as the village feeder and a new feeder would be built to serve
agriculture.
3
agricultural water pumps. Presently, a distribution substation serves both the village and the
agricultural customers, but after feeder separation, the substation will also be designated to
serve either village or agricultural customers. The distribution substation DS1 which was
previously on the mixed feeder MF1, serving mixed agricultural pumps, households and
businesses (Figure 1) will be designated as an agricultural distribution substation ADS1
(Figure 2). In this example, two of the three low voltage lines commencing from ADS1 have
been removed, while the remaining low voltage line has been extended to serve some
pumps located closer to the village.
Figure 2: Feeders separated to serve agricultural and village areas
Primary
Substation
ADS2
11 kV
feeder
33 kV line
from EHV
substation
AF1
X
33 kV/11 kV
transformer
11 kV
feeder
ADS1
VF1 (new)
X
ADL3
P customers
only
P customers
only
HH
AF2
X
New 11
kV bay
Normally
open
switch
11 kV
feeder
P customers
only
ADS3
HH
ADS4
HH
HH
X
P
HH
HH
VF2 (new)
To
other
villages
P customers
only
Anothe
r 11 kV
feeder
11 kV agricultural feeder
P
B
HH
HH
P
P
HH
P
B
P
HH
P
P
P
AF: Agricultural Feeder
VF: Village Feeder
ADL: Distribution line for agriculture
ADL: Distribution line for agric. (extended)
New Village Feeder 11 kV (see
details of HVDS in Figure 3)
Note: The layout does not refer to any particular area or village. Distances are
not to scale and they have been shrunk or exaggerated to elaborate the concept.
ADS: Distribution Substatioin for Agriculture
P
Agricultural Water Pump
HH
Household customer
B
Small business
Source: Project preparatory technical assistance consultants.
6.
Substation DS1, now designated as ADS1 has a smaller number of customers
(pumps only), and is now too far from most of the pumps. Therefore, depending on the
distances and existing substation transformer capacities, ADS1 may be relocated to a
position closer to the main area where pumps are located, and its transformer may replaced
with a new, smaller capacity transformer. As the total power requirement for agricultural
water pumping is substantially higher than the power requirements for the village, in most
situations, the existing transformer in DS1 would be rehabilitated and used in ADS1. If the
substation is relocated, AF1 would be extended to such new location, requiring a certain
length of new 11 kV line to be built.
7.
New distribution substations will be required to be installed owing to feeder
separation. The typical existing arrangement in a village is to place the distribution
substation in a central location (see DS1 in Figure 1), and to draw low voltage distribution
lines, typically using bare conductors, along public roads and pathways. Village customers
are then provided with a service drop from the closest pole. Long distribution lines drawn in
the villages using bare conductors presently, (i) cause poor service voltage to customers at
the far end of distribution lines, (ii) cause frequent interruptions and damages to transformers
owing to vegetation touching the lines, and (iii) make un-authorized use of electricity
4
convenient. Therefore, the feeder separation program also plans to restructure the
distribution network in each village, as a high voltage distribution system (HVDS).
B.
High Voltage Distribution Systems
8.
The new 11 kV village feeder (VF1) built under the feeder separation program,
depending on the extent of the village, will not serve only one location of a village, but will
traverse the village. In contrast with the present practice of placing a distribution transformer
in one location and drawing long distribution lines throughout the village, the village feeder at
11 kV will serve several new distribution substations in the village. Please see Figure 3. The
village customers are new served off two new distribution substations VDS1 and VDS2. This
will require some low voltage lines along village roadways to be converted to 11 kV lines.
Each new substation in the village will have a smaller (25 kVA) transformer serving a section
of the village, and new distribution lines to serve households and businesses in the village.
Thereby, the length of the distribution lines from the distribution substation to reach the
customers, will be shorter than at present. Shorter low voltage lines would reduce energy
losses in distribution system. Furthermore, these new distribution lines along roads and
pathways will use aerial bundled cables (ABC), which are insulated. Therefore, short
distribution lines and the use of ABC would provide (i) an improved service voltage to village
customers, (ii) completely eliminate impacts of vegetation on the lines (and vice versa,
because vegetation needs not be cleared to draw ABC lines), (iii) reduce technical losses,
and (iv) minimize unauthorized use of electricity2.
Figure 3: High voltage distribution system to serve village areas
Primary Substation
33 kV line
from EHV
substation
X
33 kV/11 kV
transformer
X
AF1
11 kV agri. feeder
VF1 (new)
HH
VDS1
(new)
New 11
kV bay
HH
HH
HH
VDL1
VDL2
To other
villages
HH
VDS2
(new)
HH
B
HH
VDL1
VDL2
HH
HH
B
New service drop
to customers
HH
New Aerial
bundled cable
distribution lines
AF: Agricultural Feeder
VF: Village Feeder (new)
VDS: Village Distribution Substatioin
To other
villages
New Village Feeder 11 kV
VDL: Distribution line for village (new)
HH
Note: The layout does not refer to any particular area or village. Distances are
not to scale and they have been shrunk or exaggerated to elaborate the concept.
B
Household customer
Small business
Service drop (new)
Source: Project preparatory technical assistance consultants.
2
11 kV lines traversing the village would continue to use un-insulated bare conductors, from which no
unauthorized connections are possible, owing to the higher operating voltage. Unauthorized connection from
the new distribution lines using ABC too, are not possible by simply placing a wire above the line, as it is done
presently off bare conductor lines.
5
9.
Alternatives to feeder separation, considering that the Government policy is to
continue providing electricity at concessionary prices for water pumping, are (i) metering
electricity use by all agricultural customers and charging on the basis of actual consumption,
(ii) single-phasing (already practiced by some DISCOMs in certain areas), and (iii) feeder
separation at low voltage level. Each alternative is discussed below.
10.
A tariff for metered agricultural customers is already included in the tariff order of
MPERC. However, metering of electricity used for agricultural water pumping has met with
limited success owing to difficulties in locating the meter, safety of the meter which has to be
located in the middle of the field at locations where the owner does not reside, and
difficulties in reading the meters. Some groups of agricultural pumps are metered at the
distribution transformer, enabling a group bill to be issued. The large majority of agricultural
pumps remain un-metered, for which there are guidelines provided by MPERC to assess the
monthly energy use. Given the policy context and the current practices, it is unlikely that
metering of electricity served to water pumps can be implemented in the near future.
11.
Single phase service during the period outside the approved hours of water pumping,
is already experimented by DISCOMs. Deviating from prudent utility practice, one of the
three conductors in the existing 11 kV mixed feeder is intentionally switched off at the
primary substation. Power continues to be available on two phases of the 11 kV feeder.
Therefore, in each distribution transformer along the 11 kV feeder, one phase out of the
three phases on the low voltage side, has the correct phase voltage of 230 V, while the other
two phases has about half the voltage. Switching off arrangement at the primary substation
is usually for the same conductor all the time. Therefore, single phase customers in the
villages are generally served by the only phase on the low voltage side that has the correct
delivery voltage. Providing supply to a majority of village customers through one phase,
causes the relevant phase winding of each distribution transformer to be overloaded.
Correspondingly, the two live phases of the 11 kV feeder are also overloaded. When
overloaded, the transformer and the two lines of the 11 kV feeder carry currents in excess of
their rated current, causing excessive energy losses and cause poor service voltage to
customers. As the village customers are aware of the phase that has the correct voltage,
both authorized and unauthorized connections are mostly served by this healthy phase on
the low voltage side. Thus, the village customer load that should be distributed among three
phases of the low voltage network too, is effectively provided only by one phase. This
causes excessive losses in the corresponding low voltage winding of the transformer, the
phase conductor of the healthy phase and in the neutral conductor. Compared with the
customer load evenly distributed between the three phases, the loss in the phase conductors
of the healthy phase on the low voltage side can be 9 times the normal loss, and the loss on
the neutral conductor too can be 9 times3. Furthermore, with three times the current in phase
and neutral conductors, the voltage drop would be six times the normal voltage drop if the
customer loads are distributed evenly between the three phases.
12.
During periods of single-phase supply, farmers too presently use their three-phase
water pumps. This is done by using the healthy supply available in one phase of the low
voltage network to produce a three-phase supply required to run the pumps, with the
assistance of an inverter, also known as a “phase splitter”. As the pump load is much higher
than the village customer load, the overloading on the healthy phase of the transformer and
distribution lines will be severe, and the current on the transformer winding of the healthy
phase would be severely stressed, causing frequent winding failures. As the transformer is
3
Under normal conditions, if the line current on each phase is I and the phase conductor resistance is R, the
2
2
power loss would be 3 x I x R = 3I R. Ideally, there will be no loss in the neutral conductor. When all
customers are connected to one phase, the current will be 3 x I and hence the loss in the phase conductor
2
2
2
would be (3xI) x R = 9I R. The loss in the neutral conductor will also be 9I R. Therefore, the total loss will be
2
2
2
9I R + 9I R = 18I R. Thus, single-phasing causes a loss of six times the loss during normal operation.
6
frequently overloaded, the protection equipment generally fixed to prevent damage, are all
disabled. Moreover, inverters causes harmonic currents, causing the water pump motors to
overheat, thus shortening the life of such motors. Thus, single-phasing causes poor voltage
to all customers and excessive losses all over the network, making this option unacceptable,
and cannot be considered as a long-term solution to the objective to ration the subsidized
electricity supply to water pumps.
13.
Feeder separation at low voltage level is another option to exercise control over
power supply to water pumps. In this approach, there will be no new 11 kV feeders built,
except for any rehabilitation and upgrades to the existing feeder. Each distribution substation
has several low voltage distribution lines. In low voltage feeder separation, these distribution
lines are rearranged such that agricultural customers will be served by one or two threephase distributors originating at the distribution substation. All other village customers will be
served by the remaining low voltage lines served by the same distribution substation. The
existing 11 kV feeder remains live throughout the day. When the service to water pumps has
to be provided, the relevant low voltage lines are switched on at the distribution substation.
These distribution substations are located in the field, by the side of roadways or other public
property, and they are unmanned. As there are tens of thousands of such distribution
substations, it is not possible or economical to station operators at each such location to
switch the agricultural services on and off. Therefore, the option available is to provide
switches on each low voltage line and then operate such switches through a wireless signal
issued from a central control centre. A pilot scheme has been implemented by DISCOM-C,
and the results indicate good energy savings. However, the constraint is the requirement to
use a control system located at isolated distribution substations, which are exposed to
possible damage and vandalism. Attempts to damage the control equipment at the
distribution substation is likely to be from persons who seek longer hours of supply for
agricultural water pumps. The pilot project has introduced monitoring of the control system to
indicate any vandalism. However, in spite of the encouraging results of savings in
commercial losses, the DISCOMs do not consider low-voltage feeder separation as a long
term solution to the need to ration electricity supply to water pumps. The reasons are (i) the
need to maintain contactors (switches) and associated control systems located at tens of
thousands of distribution substations scattered over vast areas, and the (ii) possibility of
vandalism of such control equipment because the distribution substations are unmanned
and with no access control.
C.
Previous Experience in Feeder Separation and HVDS
14.
Feeder separation and HVDS in rural areas have been implemented on a pilot basis
by DISCOM-C in Bhopal and in other states on India. Implementation of phase 1 of the
feeder separation program (funded by the Rural Energy Corporation and GOMP) 4 is
presently in progress, but post-implementation results are not available yet. In addition,
HVDS have been installed in urban areas in MP. For a pilot project implemented by
DISCOM-C in the Gharelu feeder serving a rural area, Table 2 shows the conditions before
and after the implementation of the project. The Gharelu feeder was previously a mixed
feeder, serving both agriculture and villages. The feeder had the facility to switch off one
phase at the primary substation located in Lambakheda. Therefore, village customers were
able to use electricity during the period of single-phase operation of the mixed feeder. The
old feeder was designated as the agricultural feeder and a new 11 kV feeder was built. This
new feeder commenced from the Lambakheda primary substation and serves nine villages.
The project included addition of new transformers in the villages, conversion of certain low
voltage lines to high voltage feeders, and replacement of bare-conductor low voltage lines
4
Phase 2 of the feeder separation program is proposed to be financed by ADB, GOMP and the DISCOMs.
7
with aerial bundled cables or armored cables5. Previously in the village, there were 339
metered customers, 76 un-metered customers 6 and an estimated 43 unauthorized
connections. All the existing village households and other customers were provided with a
new service connection and a new meter. The meter was fixed at a visible location in each
premise.
Table 2: Results of the HVDS installed at Islamnagar in DISCOM-C
Primary substation: Lambakheda
Feeder name: Gharelu Village: Islamnagar
Distribution circle: Entkhedi DC
HVDS
Month
Input energy at
distribution
transformer
MWh/month
Energy Sold
at customer
end
MWh/month
Total energy Loss
(technical and
commercial)
MWh/month
%
Before project
Dec 2009
161.0
48.0
implementation
After project
Oct 2010
52.2
38.0
implementation
Note: The information is for one village and shows the benefits of HVDS only.
Source: DISCOM-C estimates.
113
70.2%
14
27.2%
15.
In the pilot project in Islamnagar, energy sold after project implementation is lower
than before, because previously, there were un-metered customers, whose consumption
was estimated on the basis of the approved regulatory limit, and included as sales. With all
customers provided with meters, and all customers receiving bills based on the actual
consumption, the consumption has decreased. Based on the estimated number of
connections (metered, un-metered and unauthorized) before installation of the HVDS, the
average consumption per village customer decreased from 105 to 83 kWh/month, when
HVDS was installed. The Ghasipur feeder served four more villages in addition to
Islamnagar, and these villages have not been installed with HVDS or feeder separation.
Therefore, the combined impacts of feeder separation and HVDS, considering the preproject energy served to the old mixed feeder against the data, cannot be compared at this
stage.
16.
HVDS has been installed in urban areas of MP. Information provided by DISCOM-C
about several HVDS schemes implemented in year 2009 in urban areas, indicate that for
each feeder converted to HVDS, reported post-implementation losses between 12.5% and
30.3% with an average of 19.14% (Table 3).
Table 3: Results of HVDS implementation in urban areas in DISCOM-C
Feeder
Month/year of
implementation
No of legal
consumers
Billed sales
(kWh/month)
Supplied energy
(kWh/month)
Total technical
and commercial
loss
Balaji
Nagar
Piriya
Mohalla
Harijan
Mohalla
Bhopal Urban
Janta
BDA
Qrts.
Colony
Om
Nagar JJ
Nai
Basti
Jatkhedi
JJ
Gwalior urban
Lala Ka
Mal
Bazar
Road
Padav
Sep-09
Sep-09
Sep-09
Jun-10
Sep-09
Oct-09
Apr-10
Dec-09
Aug-10
Aug-10
Aug-10
Before
after
Before
after
Before
after
Before
70
100
8,700
11,100
17,700
13,000
50.8%
Nil
49
Nil
4,900
15,000
6,100
na
14
31
1400
3,200
2,900
3,900
51.7%
Nil
349
Nil
28,000
129,000
32,000
na
Nil
496
Nil
52,000
140,000
62,000
na
190
209
15,000
31,000
105,000
39,000
85.7%
63
180
5000
23,000
90,000
33,000
94.4%
3
265
0
40,000
133,000
48,000
100.0%
2,533
2,540
300,650
635,000
891,000
827,000
66.3%
1,672
2,343
218,642
641,170
768,000
823,000
71.5%
2,266
2,236
410,159
853,454
758,000
1,028,000
45.9%
after
14.6%
19.7%
17.9%
12.5%
16.1%
20.5%
30.3%
16.7%
23.2%
22.1%
17.0%
Note: The information is for Bhopal urban and Gwalior urban areas of DISCOM-C, which were highly prone for
unauthorized connections. On certain feeders, almost all connections were unauthorized. After HVDS, losses of
all the urban feeders have declined to the range between 12.5% to 30.3%.
Source: DISCOM-C estimates.
5
An armored cable is a fully insulated electricity conductor, with a protective armor consisting of a mesh of steel wire. Their
typical application is as underground buried cables, with the steel armor providing protection against unintentional mechanical
damage.
6
MPERC allows un-metered household customers.
8
D.
Energy Efficiency and GHG Emission Reduction
17.
Technical losses in distribution networks are reduced through feeder separation and
HVDS. Commercial loss reduction may vary after feeder separation and HVDS, depending
on how much of the commercial losses would be converted to sales. Reduced technical
losses have clear benefits by way of reduced purchases from transmission, thereby reducing
purchases from generation. Any savings in thermal power generation would result in savings
of greenhouse gas (GHG) emissions from power plants. These power plants may either be
within MP or outside the state. As commercial losses may be converted to sales, savings in
commercial losses were not considered in the estimation of GHG emission reduction.
18.
A comprehensive analysis of pre-project technical losses using meters at input and
output points of a rural distribution network would not be possible owing to unmetered and
unauthorized service connections that would prevent accurate measurement of output from
the network. Input to the network, however, can be measured. Therefore, the assessment of
technical loss savings from feeder separation and HVDS network was based on a model of a
typical rural network. The physical model was defined as follows:
Length of 11 kV feeder from the 33 kV/11 kV substation
Type of conductor used for the 11 kV feeder
Capacity of the distribution transformer
Length of 400 V, 3-phase distribution lines from the transformer
Type of conductor used for distribution lines
Current carrying capacity of each distribution line
Number of village household/small business customers
Village customer load profile
Customer distribution along LV feeders
Number and rating of pumps served through the LV lines
5 km
7/4.10 mm (Racoon7)
250 kVA
3 feeders 1.8 km each
All aluminum bare
conductor 25 mm2 (Gnat)
140 A
600 (approximately)
typical profile of a village
uniformly distributed
9 pumps, each 10 hp
19.
Present operating pattern: 3-phase supply is provided for eight hours each day.
Thereafter, one phase of the 11 kV feeder is switched-off at the primary substation, and for
sixteen hours, this situation prevails. It was assumed that owing to this practice of “singlephasing” for several years, 80% of village household customers (both legal and illegal
connections) have got their service lines shifted to be served from the healthy phase of the
distribution lines. The balance 20% of village customers would receive a poor quality of
supply during this sixteen-hour period of single-phase supply each day.
20.
The calculated technical losses of this feeding arrangement are given in Table 4. The
highest technical loss will be on LV distribution lines. The highest overall technical loss
(25.2% of input to 11 kV feeder) occurs if the 3-phase service is provided during the daytime. If the 3-phase service period is varied from day to day, the average loss will be 24.8%
of the input to the network at 11 kV. The average technical losses in the existing network
were therefore considered to be 24% of the input to the distribution network at 11 kV.
7
Bare (ie un-insulated) electrical conductors used in power transmission and distribution are identified by the
number of strands and the diameter of each strand. Additionally the cross-sectional area and a code name is also
used.
9
Table 4: Daily energy input and technical losses in a typical distribution network with mixed
village and agricultural customers
Pump
Operation
interval
(3-phase
service
available)
Total Input
at 11 kV
LV Loss
Transformer Loss
11 kV feeder Loss
(kWh/day) (kWh/day)
%
(kWh/day)
%
(kWh/day)
00:00 -08:00
2,458.2
3.2
0.1%
29.7
1.2%
596.4
08:00-16:00
2,183.7
2.9
0.1%
28.6
1.3%
519.3
16:00- 24:00
2,602.7
3.3
0.1%
30.2
1.2%
583.9
Average
2,414.9
3.1
0.1%
29.5
1.2%
566.5
All % losses are calculated as a share of the input at 11 kV.
Source: Estimates by project preparatory technical assistance consultants.
%
24.3%
23.8%
22.4%
23.5%
Total Loss
(kWh/day)
629.4
550.8
617.4
599.2
%
25.6%
25.2%
23.7%
24.8%
21.
Feeder separation would avoid the need for switching off the village feeders, and the
village customers will be served throughout the day. The agricultural pumps will be
separately served for eight hours each day. The project will also ensure that single-phase
households and other customers in the village would be distributed between the three
phases, thus minimizing losses in the LV phase conductors as well as the neutral conductor
along each LV feeder. The analysis was extended to assess the losses owing to even
distribution of village customers, in the first case, with feeder separation only. The results of
the analysis are given in Table 5. The calculated technical losses would be 18.8% of input at
11 kV, a reduction of 6% from the existing loss level. For subsequent analysis, the technical
loss reduction was considered to be 3%, a conservative assessment compared with the 6%
saving calculated using the model. The assessment of energy savings at generation level is
given in Table 6.
Table 5: Daily energy input and technical losses in a typical distribution network with village
customers only (after feeder separation)
Pump Operation
Interval (3phase service
available)
Total
Input at
11kV
LV Loss
Transformer Loss
11kV Feeder Loss
(kWh/day) (kWh/day)
%
(kWh/day)
%
(kWh/day)
00:00-08:00
2,458.2
3.2
0.1%
29.7
1.2%
596.4
08:00-16:00
2,183.7
2.9
0.1%
28.6
1.3%
519.3
16:00-24:00
2,602.7
3.3
0.1%
30.2
1.2%
583.9
Average
2,414.9
3.1
0.1%
29.5
1.2%
566.5
All % losses are calculated as a share of the input at 11 kV.
Source: Estimates by project preparatory technical assistance consultants.
%
24.3%
23.8%
22.4%
23.5%
Total Loss
(kWh/day)
629.4
550.8
617.4
599.2
%
25.6%
25.2%
23.7%
24.8%
Table 6: Assessment of energy savings at generation level, owing to reduced technical losses
Description
Technical loss savings at 11 kV level, for all
DISCOMs
Equivalent power generating capacity avoided
units
Amount
GWh/year
487.8
MW
65.5
Transmission loss rate approved by MPERC
GWh/year
4.08%
Therefore, savings at the generation (net) level
GWh/year
508.6
Source: Estimates by project preparatory technical assistance consultants.
Notes
equivalent to only 3% reduction of
technical losses, calculated using
data on total input to the 11 kV
network in MP
Based on an annual capacity factor
of 0.85
Published in Tariff Order 2010-11
Calculated
22.
Agricultural water pumps are presently operated for a period longer than the period
stipulated. WIth the use of phase splitters, these pumps are operated during the period when
one phase of the 11 kV feeder is switched off. This further increases the technical losses,
owing to severe overloading of the healthy phase of the distribution network and the
10
resultant increase in the neutral current. After feeder separation, the pumps can be provided
power for a fixed period of operation, adequate for agricultural purposes. The use of pumps
will be limited to such period. Therefore, the energy used for the present over-use of pumps
will be saved. The energy savings owing to restricting the use of pumps to eight-hours per
day was estimated as given in Table 7.
Table 7: Estimate of Savings Owing to Avoided Over-use of Agricultural Pumps
Description
units
Amount
Notes
Energy allowed in the tariff
order for agricultural
customers reflects an average
use of 6 hours/day
estimated
Estimated based on the
allowed energy use of 7225
GWh/year for agriculture in
MP
Estimated hours of operation at which regulatory
allowance will be exhausted
hours/day
6.0
Additional period of use with splitters etc
hours/day
2.5
Hence, estimated actual use for Agric.
GWh/year
10,235.3
GWh/year
9,633.2
calculated
GWh/year
602.1
calculated
MW
80.9
GWh/year
4.08%
calculated
Published in Tariff Order 201011
calculated
With 8-hour availability, estimated actual use for
agriculture after feeder separation
Therefore, estimated savings in actual use in
agric. owing to feeder separation
Equivalent power plant capacity
Transmission losses approved by MPERC
Therefore, savings at the generation (net) level
GWh/year
627.7
Source: Estimates by project preparatory technical assistance consultants.
23.
The total saving in technical losses and avoided wasteful use in agriculture is
therefore estimated to be 508.6 + 627.7 = 1136.3 GWh. The savings in losses would cause
a reduction in purchases from transmission, and therefore lead to reduced generation, either
in MPGENCO or from central power plants. As India’s power generation is dominated by
fossil fuels, the reduced generation would cause a reduction in CO2 emissions. A key
parameter to calculate emission reductions, is the emission factor, measured in kg CO2 per
kWh saved. UNFCC8 has standardized and published calculation methodologies to assess
the emission factor of public electricity systems. Central Electricity Authority (CEA) of India
calculates and publishes the emission factor for the Indian grid, using the UNFCCCapproved methodology ACM0002 version 6 9 . The calculated emission factor for India,
published by CEA in March 2011 is 0.89 kg of CO2 per kWh for year 2009-10. In 2007-8, the
emission factor has been 0.81, thus the Indian grid is showing an increasing trend of the
emission factor. However, a conservative estimate of 0.81 was used, to calculate the
emission reductions expected as a result of the feeder Separation and HVDS. The
calculations are summarized in Table 8.
Table 8: Estimation of annual savings of CO2 emissions owing to reduced technical losses
Description
units
Amount
Savings in technical losses and avoided
GWh/year
1136.3
wasteful use in agriculture
Emission factors published by Central
Electricity Authority for India, after adjustment
kgCO2/kWh
0.81
for imports from Bhutan
Avoided GHG emissions owing to technical
tonneCO2/
920,369
loss reduction
year
Source: Estimates by project preparatory technical assistance consultants.
8
9
Notes
calculated earlier, as at the point
of generation
Calculated
Calculated
United Nations Framework Convention on Climate Change.
ACM002 is a methodology approved by UNFCCC for the calculation of emission factors to assess emission
reduction from grid-connected renewable energy-based power plants. However, UNFCCC recommends that
this assessment methodology may also be used to estimate the emission reductions owing energy efficiency
as well. Please see page 15 of the CDM Methodology Booklet
http://cdm.unfccc.int/methodologies/documentation/meth_booklet.pdf#ACM0002
11
24.
The above is a conservative estimate of the annual savings, owing to the following
reasons: (i) India’s grid emission factor indicates an increasing trend but the above analysis
uses the lowest emission factor published over the past five years, (ii) reduction in technical
losses has been conservatively assessed to be 3%, whereas, the reduction may exceed 6%
in typical cases in MP, and (iii) the annual quantity of energy savings will increase as the
seperated feeders and HVDS delivers more energy over its their economic life of 25 years.