static synchronous series compensator and gate controlled series capacitor

1. FACTS DEVICES
Presented By :
Rushi Bhuva (15EE008)
Manan Desai(15EE021)
Chaitanya K. (15EE034)
1. Static Synchronous Series Compensator (SSSC)
2. Gate Controlled Series Capacitor (GCSC)

2. STATIC SYNCHRONOUS SERIES COMPENSATOR /
CAPACITOR (S3C / SSSC)

3. Intro
Static Synchronous Series Compensator (SSSC) is a modern power quality
FACTS device that employs a voltage source converter connected in series to a
transmission line through a transformer. The SSSC operates like a controllable
series capacitor and series inductor. The primary difference is that its injected
voltage is not related to the line intensity and can be managed independently.
This feature allows the SSSC to work satisfactorily with high loads as well as
with lower loads.

4. The Static Synchronous Series
Compensator has three basic
components:
a. Voltage Source Converter
(VSC)– main component
b. Transformer – couples the
SSSC to the transmission line
c. Energy Source – provides
voltage across the DC
capacitor and compensate for
device losses

5. A typical SSSC controller connected in a transmission line

6. ★ The SSSC has been applied to different power system studies to improve the
system performance.
★ A static synchronous Series Compensator operated without an external energy
source as Reactive Power with output voltage.
★ SSSC controls the electric power flow by increasing or decreasing the overall
reactive voltage drop across the transmission line.
★ The SSSC FACTS device can provide either capacitive or inductive injected
voltage compensation.
★ If SSSC-AC injected voltage, (Vs), lags the line current IL by 90º, a capacitive
series voltage compensation is obtained in the transmission line .
★ if leads IL by 90º, an inductive series compensation is achieved.

7. ★ Figure 1 shows a single line
diagram of a simple Transmission
line with an inductive transmission
reactance, XL, connecting a
sendingend (S.E.) voltage source,
and a receiving end (R.E.) voltage
source, respectively.
Theory of SSSC

8. (i)
(ii)
(iii)
(iv)

9. expression of power flow given in eq.1 and eq. 2 become :
Where Xeff is the effective total transmission line reactance between its sending and Receiving power system
ends, including the equivalent “variable reactance” inserted by the equivalent injected voltage (Vs)
(Buck or Boost) by the SSSC-FACTS Compensator.

10. DIGITAL SIMULATION MODEL

11. The feeding AC network is represented by an equivalent Thevenin is at
(bus B1) where the voltage source is a 230 kV with 10000 MVA short
circuit level (resistor 0.1 pu and an equivalent reactance of 0.3 pu)
followed by the 230 kV radial transmission line connected to bus B2.
The full system parameters are given in Table 1.
DIGITAL SIMULATION MODEL

13. Operation of SSSC
● A SSSC can work like a controllable serial condenser and a serial reactance.
● The main difference is that the voltage infected through a SSSC is not related to the line
intensity and can be
● controlled independently.
● SSSC can be used with excellent results with low loads as well as with high loads.
● The main function of the SSSC device is to regulate the feeder power flow.
● This can be accomplished by either direct control of the AC line current or indirect control by
compensating the impedance,
● Xs via a (Buck/Boost) compensating injected voltage, Vs.
● SSSC is made to operate capacitor by inducing a voltage 90 deg lagging to that of the line
current.
● It is also operated as an inductor by making the induced voltage lead the line current by 90 deg.
● The simulation results of both inductive and capacitive regions are obtained.

14. ● These devices (SSSC, DVR, UVC) correct the voltage when there is a fault
in the network but also have a lot of advantages in normal use, when there
are no disturbances.
● Due to the continuous voltage injection and in combination with a properly
structured controller, it is possible to control the power factor of
connected loads.
● In the interconnected distribution network topologies, the additional
voltage with its controllable magnitude and phase, can be used to work on
the power flows.
Advantages

15. ● It can also help to cover the capacitive reactive power demand if cable
networks, which is higher than in aerial lines, mainly during low load
periods that cause inadmissible load elevations.
● It balances loads in interconnected distribution networks, providing a
balanced system.
● It reduces the harmonics caused because of the use of distributed
electrical generation pants at a distribution network level, by active filtering
by injecting voltage with the converter at the load side.
Advantages

16. CONCLUSION
1. The SSSC device is a controlled/injected
voltage source that injects a near sinusoidal AC
voltage in series with the transmission line.
2. The dynamic power flow in the Transmission
line always decreases when the injected
voltage by the SSSC in an inductive reactance
mode and the power flow increases when the
injected voltage by the SSSC in a capacitive
reactance mode.
3. SSSC with its superior characteristics like
immunity to sub synchronous resonance, power
oscillation damping, quick response time, wider
control range, and lower maintenance cost can
be used effectively for series compensation of
the Transmission line.
4. Thus due to above superior characteristics
SSSC is going to replace all the conventional
series compensators.

17. Thanks!