Presented by:
Dr Ahmed Massoud
Dr Ahmed Massoud University of Strathclyde 1

FACTS
1. POWER SYSTEMS
2. FACTS definition
3. FACTS controllers
4. Parallel controllers
5. Series controller
6. Series-parallel controllers
7. HVDC
8. Others
Dr Ahmed Massoud University of Strathclyde 2

POWER SYSTEM
GENERATION TRANSMISSION DISTRIBUTION
Dr Ahmed Massoud University of Strathclyde 3

Characteristics of Transmission
Bottlenecks
• Steady-State Power Transfer Limit
• Voltage Stability Limit
• Transient Stability Limit
• Thermal Limit
• Short-Circuit Current Limit
Dr Ahmed Massoud University of Strathclyde 4

Conventional System Solutions to enhance Transmission capability
• Series Capacitors (X)
• Switched Shunt-Capacitor and Reactor (V)
• Transformer LTC’s (V)
• Phase Shifting Transformers ( δ )
• Synchronous Condensers (V)
Dr Ahmed Massoud University of Strathclyde 5

FACTS
1. POWER SYSTEMS
2. FACTS definition
3. FACTS controllers
4. Parallel controllers
5. Series controller
6. Series-parallel controllers
7. HVDC
8. Others
Dr Ahmed Massoud University of Strathclyde 6

F A C
T Systems (FACTS)
FACTS
AC transmission systems incorporating the power electronic-based to enhance controllability and increase power transfer capability.
FACTS Controllers
A power electronic based system & other static equipment that provide control of one or more AC transmission parameters.
Dr Ahmed Massoud University of Strathclyde 7

Power Electronics Devices For
FACTS Controllers
Line-Commutated
• Thyristors
• Electrically Triggered (ETT)
• Light Triggered (LTT)
Self-Commutated
•
Gate-Turn Off Thyristors (GTO)
• Insulated Gate Bipolar Transistors (IGBTs)
•
Integrated Gate Commutated Thyristors (IGCTs)
Dr Ahmed Massoud University of Strathclyde 8

FACTS
1. POWER SYSTEMS
2. FACTS definition
3. FACTS controllers
4. Parallel controllers
5. Series controller
6. Series-parallel controllers
7. HVDC
8. Others
Dr Ahmed Massoud University of Strathclyde 9

F A C T S c o n tro lle rs lin e c o m m u ta te d
S e rie s thy ris to r c o ntro lle d s e rie s c a pa c ito r
(TC S C )
B a c k -to -b a c k c o nv e ntio na l HVD C
S h u n t thy ris to r c o ntro lle d re a c to r o r s w itc he d c a pa c ito r
(TCR or TS C)
S e rie s -s e rie s inte rline po w e r flo w c o ntro lle r
(IP F C ) fo rc e d c o m m u ta te d
S e rie s static synchronous series com pensator
(S S S C )
S h u n t s ta tic s y nc hro no us c o mpe ns a to r
(S TATC O M )
S h u n t-S e rie s unifie d po w e r flo w c o ntro lle r
(UP F C )
B a tte ry e ne rgy s to ra ge (B E S S )
S e rie s -s e rie s inte rline po w e r flo w c o ntro lle r
(IP F C )
S upe rc o nduc ting
M a gne tic E ne rgy
S to ra ge (S M E S )
Dr Ahmed Massoud University of Strathclyde
B a c k -to -b a c k light HVD C
10

___
V s X
P
=
V V s r
X sin
δ
δ
V s
I.X
V r
I
___
V r
Dr Ahmed Massoud University of Strathclyde 11

Controllable parameters
Control of the line impedance current and active power control
Control of angle current and active power control
Series voltage injection
Current, active, and reactive power control
Parallel voltage injection
Current, active, and reactive power control
Dr Ahmed Massoud University of Strathclyde 12

Series control
V 1 X series X V 2
V series
P=V
1
.V
2
.sin(
δ
)/(X-X s e rie s
)
Dr Ahmed Massoud
δ
University of Strathclyde
I
V 1
V 2
13

V 1
Parallel control
X V 2
Q
P= V
1
.V
2
.sin(
δ
)/X
Dr Ahmed Massoud
δ
University of Strathclyde
V1
I
I
V 1
14
V 2

Series and parallel control
V 1 X series X V 2
V series
Q
Dr Ahmed Massoud University of Strathclyde 15

FACTS
1. POWER SYSTEMS
2. FACTS definition
3. FACTS controllers
4. Parallel controllers
5. Series controller
6. Series-parallel controllers
7. HVDC
8. Others
Dr Ahmed Massoud University of Strathclyde 16

Static VAR compensator
• TCR = Thyristor Controlled Reactor
• TSR = Thyristor Switched Reactor
• TSC = Thyristor Switched Capacitor
• MSC = Mechanically-Switched Capacitor
• MSR = Mechanically-Switched Reactor
• FC = Fixed Capacitor
• Harmonic Filters
Dr Ahmed Massoud University of Strathclyde 17

Thyristor Controlled Reactor (TCR)
Parallel-connected static var generator or absorber
● Output is adjusted to exchange capacitive or inductive current
● Maintain or control specific parameters of the electrical power system
(typically bus voltage).
● Thyristor-based Controllers
● Lower cost alternative to STATCOM
Dr Ahmed Massoud University of Strathclyde 18

2
0
-2
-4
-6
-8
8
6
4
Voltage
Current
0.005
0.01
Time (s)
0.015
Firing angle of 90
0.02
1
0.667
0.333
0
-0.333
-0.667
-1
0 0.005
0.01
Time (s)
0.015
Firing angle of 135
0.02
Dr Ahmed Massoud
Thyristor Controlled
Reactor
University of Strathclyde 19

Thyristor Switched Capacitor (TSC)
Dr Ahmed Massoud University of Strathclyde 20

Static Synchronous Compensator
(STATCOM)
● Parallel-connected static var compensator
● Capacitive or inductive output current controlled independently of the ac system voltage
21 Dr Ahmed Massoud University of Strathclyde

Inverter
(IGBT, GTO, or GCT)
L
Q
V dc
Dr Ahmed Massoud
P (if no energy source is provided)
University of Strathclyde 22

Parallel Active Power Filters
(Parallel APF)
• Reactive power
• Compensation
• Source current’s higher
• Harmonics compensation
• DC element voltage control
Dr Ahmed Massoud University of Strathclyde 23

3-phase
supply i s e i
L i f
L v
Shunt active filter
non-linear load
Shunt active power filter single line diagram
Dr Ahmed Massoud University of Strathclyde 24

i dc
(t) v dc
(t)
+
_
C
S a v an
S b
S' a v bn
S' b
S c v cn
S' c
L a
L b
L c i a i b i c e a e b e c
Two level voltage source inverter
Dr Ahmed Massoud University of Strathclyde 25

Dr Ahmed Massoud University of Strathclyde 26

1. Two level Voltage source inverter
2. Multilevel voltage source inverter
3. Series connection
Current source inverter ?
Dr Ahmed Massoud University of Strathclyde 27

1. Neutral point clamped
2. Cascaded
3. Flying capacitor
Dr Ahmed Massoud University of Strathclyde 28

Neutral point clamped
Dr Ahmed Massoud University of Strathclyde 29

Dr Ahmed Massoud University of Strathclyde 30

Dr Ahmed Massoud University of Strathclyde 31

E
S1
S4
S5
E
S8 i load
>0
Dr Ahmed Massoud
D1 i load
E
D4
2E
D5
E
University of Strathclyde i load
<0
D8 i load
2E
32

E
i l o a d
E i l o a d
D 3 S 4 S 3 D 4
E
D 5
S 5
E i load
>0
Dr Ahmed Massoud
S 8
E
University of Strathclyde i load
<0
D 8
33
E

i l o a d
E i l o a d
E
D 3 S 4 S 3 D 4
0
E
D 7 S 8 i load
>0
Dr Ahmed Massoud
E
University of Strathclyde
S 7 i load
<0
D 8
34
0

i l o a d E
E
S 3
D 3 S 4
-E
E
D 7 i load
>0
Dr Ahmed Massoud
D 6
E
S 7
University of Strathclyde i load
<0
S 6
D 4 i l o a d
35
-E

D 2 i l o a d E
S 2
E
S 3
D 3
-2 E
E
D 7 i load
>0
Dr Ahmed Massoud
D 6
E
S 7
University of Strathclyde i load
<0
S 6 i l o a d
36
-2 E

3
2
1
0
-1
-2
-3
0 0 .0 2 0 . 0 0 5 0 .0 1
T i me (s )
University of Strathclyde
0 .0 1 5
Dr Ahmed Massoud 37

Dr Ahmed Massoud University of Strathclyde 38

Output of two-level inverter (PWM)
-1
-2
1
0
-3
0
3
2
0. 0 05 0 .0 1
T im e (s )
0 .0 1 5 0 . 02
Dr Ahmed Massoud University of Strathclyde 39

FACTS
1. POWER SYSTEMS
2. FACTS definition
3. FACTS controllers
4. Parallel controllers
5. Series controller
6. Series-parallel controllers
7. HVDC
8. Others
Dr Ahmed Massoud University of Strathclyde 40

Series Capacitors Applied For:
Increasing Power Transfer
Increasing Stability Limits
Improving Voltage Profile
Improving Load Division
Dr Ahmed Massoud University of Strathclyde 41

Series Active Power filter (Series
APF)
• Voltage harmonics compensation
• Stability improvement
• Current harmonics blocking
42 Dr Ahmed Massoud University of Strathclyde

Static Synchronous Series
Compensator (SSSC)
● Output voltages in quadrature with, and controllable independently of, the line current
● Control the transmitted electric power.
● May include energy storage to enhance the dynamic behavior of the power system by additional temporary real power compensation, to increase or decrease momentarily, the overall real (resistive) voltage drop across the line.
Dr Ahmed Massoud University of Strathclyde 43

Thyristor Controlled Series
Capacitor (TCSC)
● Smooth control of series capacitive reactance
Dr Ahmed Massoud University of Strathclyde 44

FACTS
1. POWER SYSTEMS
2. FACTS definition
3. FACTS controllers
4. Parallel controllers
5. Series controller
6. Series-parallel controllers
7. HVDC
8. Others
Dr Ahmed Massoud University of Strathclyde 45

Unified Power Flow Controller
(UPFC)
●
A combination of STATCOM and SSSC coupled via a common dc link
● Bi-directional flow of real power between the SSSC and the STATCOM
Unified Power Flow Controller = Static Synchronous Series Compensator +
STATCOM
Dr Ahmed Massoud University of Strathclyde 46

In v e r te r
(I G B T , G T O , o r G C T )
S e r ie s c o n v e r te r
C
S h u n t c o n v e r te r
L
Dr Ahmed Massoud University of Strathclyde 47

Unified Power Quality
Conditioner (UPQC)
• Source current harmonics compensation
• System stability improvement
• Reactive power compensation
• DC element voltage control
• Voltage harmonics compensation
Dr Ahmed Massoud University of Strathclyde 48

Combination of active power filter and passive filter
Supply Load
Active filter
Passive filter
Parallel active power filter and passive filter
Dr Ahmed Massoud University of Strathclyde 49

Supply Load
Passive filter
Active filter
Parallel active power filter in series with passive filter
Dr Ahmed Massoud University of Strathclyde 50

Supply
Active filter
Load
Passive filter
Series active power filter and parallel passive filter
Dr Ahmed Massoud University of Strathclyde 51

Supply
Active filter
Load
Active filter
Series and parallel active power filter (unified power quality conditioner UPQC)
Dr Ahmed Massoud University of Strathclyde 52

Series VS. Parallel
● Series is more powerful in controlling the current/power flow and damp oscillations
● Parallel is more effective in voltage control and damping of voltage oscillations
Dr Ahmed Massoud University of Strathclyde 53

FACTS
1. POWER SYSTEMS
2. FACTS definition
3. FACTS controllers
4. Parallel controllers
5. Series controller
6. Series-parallel controllers
7. HVDC
8. Others
Dr Ahmed Massoud University of Strathclyde 54

Grid 1
V 1
V 2
Grid 2
Dr Ahmed Massoud University of Strathclyde 55

High voltage DC transmission (HVDC)
It is economically attractive:
• over a long distance from a remote generating to the load centre (>300 miles)
• underwater transmission
• when connecting two AC systems at two different frequencies
Dr Ahmed Massoud University of Strathclyde 56

Advantages of HVDC
• No limits in transmitted distance.
• Fast control of power flow, which implies stability improvements.
• Direction of power flow can be changed very quickly.
• HVDC can carry more power for a given size of conductor
• improved transient stability
• dynamic damping of the electric system oscillations
• Require less space compared to ac for same voltage rating and size
• Ground can be used as a return conductor
• No charging current
• HVDC transmission limits short circuit currents
Dr Ahmed Massoud University of Strathclyde 57

Cost
AC Cost
DC Cost
Dr Ahmed Massoud
600-800Km
University of Strathclyde
Distance
58

The HVDC technology
The fundamental process that occurs in an HVDC system is the conversion of electrical current from AC to DC
(rectifier) at the transmitting end, and from DC to AC
(inverter) at the receiving end.
1. Natural Commutated Converters. The component that enables this conversion process is the thyristor (high power and low switching frequency).
2. Forced Commutated Converters. It uses GTO or IGBT.
They are known as VSC (Voltage Source Converters).
Dr Ahmed Massoud University of Strathclyde 59

HVDC transmission system
Terminal A
Positive pole
12 pulse Y Y
Δ
Y
L d
DC filter
AC system
A
AC filter and
power factor correction capacitors
Y Y
Δ
Y
Negative pole
12 pulse
Dr Ahmed Massoud
DC filter
L d
University of Strathclyde
HVDC transmission
line
Terminal B
AC system
B
60

Components of HVDC
1.
Converter: at one side rectifier and the other inverter each converter consists of a positive pole and a negative pole each pole consists of 6 pulse converters connected through star-delta and star-star transformer to yield 12 pulse converter
2.
On the AC side:
* AC filters to reduce the current harmonics generated from the converters
* Power factor correction capacitors to supply the lagging reactive power
3.
On the DC side: smoothing reactor and DC filters to filter the ripple in the DC currents
Dr Ahmed Massoud University of Strathclyde 61

12 pulse line frequency converter
Objectives:
1. Reduce current harmonics on AC side
2. Reduce voltage ripple on DC side
3. High power
12 pulse converter consists of two six-pulse converters connected through star-star and delta-star transformer
The 2 converters are connected in series from the DC side and parallel from the AC side
Dr Ahmed Massoud University of Strathclyde 62

i a i a1
2N:1 as1 i as1 cs1 n1 bs1 i a2
Dr Ahmed Massoud i as2 as2 cs2 n2 bs2
University of Strathclyde
I d
L d v d1 v d2
63

1. Monopolar: Having one conductor and the ground is the return path
DC pole return earth
64 Dr Ahmed Massoud University of Strathclyde

2. Bipolar: There are two conductors (poles). One operates with positive polarity and the second with negative. During fault of one them, the bipolar acts as a monopolar
+ DC pole
Dr Ahmed Massoud return earth
- DC pole
University of Strathclyde 65

HVDC Light
1. HVDC Light unit sizes range from a few tens of MW to presently 350 MW and for DC voltages up to ± 150 kV and units can be connected in parallel.
2. HVDC Light consists of two elements: converter stations and a pair of cables. The converter stations are Voltage
Source Converters (VSCs) employing Self-commutated switch
66 Dr Ahmed Massoud University of Strathclyde

FACTS
1. POWER SYSTEMS
2. FACTS definition
3. FACTS controllers
4. Parallel controllers
5. Series controller
6. Series-parallel controllers
7. HVDC
8. Others
Battery Energy Storage System
Super conducting material
Dr Ahmed Massoud University of Strathclyde 67