Application of Synchronous Static Series Compensator (SSSC) on
Enhancement of Voltage Stability and Power Oscillation Damping
ABSTRACT:
This paper investigates the problem of controlling
and modulating power flow in a transmission line using a Synchronous Static
Series Compensator (SSSC). The studies, which include detailed techniques of
twelve pulse and PWM controlled SSSC, are conducted and the control circuits
are presented. The developed control strategies for both twelve-pulse and
PWM-controlled SSSC use direct manipulations of control variables instead of typical
d-q transformations. The complete digital simulation of the SSSC within the
power system is performed in the MATLAB/ Simulink environment using the Power
System Block set (PSB). Simulation results validate that Voltage and Power
Oscillation can be damped properly using of Synchronous Static Series
Compensator (SSSC).
KEYWORDS:
1. SSSC
2.
Reactive compensation
3. Control
strategy
4.
FACTS
5. PWM
control
6. Voltage stabilization.
6. Voltage stabilization.
SOFTWARE: MATLAB/SIMULINK
FUNCTIONAL BLOCK DIAGRAM:
Fig
1. Functional model of SSSC
CIRCUIT DIAGRAM:
Fig
2. Static Synchronous Series Compensator (SSSC) used for power oscillation
damping
EXPECTED SIMULATION RESULTS:
Fig 3. A. SSSC Dynamic Response for Reactive Power
Fig 3 .B. SSSC Dynamic Response
for Voltage
Fig 4. A. System without SSSC under a three-phase fault for Reactive Power
Fig 4. B. System without SSSC under
a three phase fault
for Voltage
Fig 5. A. System with SSSC under a three-phase fault for Reactive Power 
Fig 5.
B. System with SSSC under a three-phase fault for Voltage
CONCLUSION:
This
paper analyzed the problem of controlling and modulating power flow in a
transmission line using a Synchronous Static Series Compensator (SSSC). The
studies, which include detailed techniques of twelve pulse and PWM controlled
SSSC, are conducted and the control circuits are presented. The SSSC operating
conditions and constraints are compared to the operating conditions of other
FACTS devices, showing that the SSSC offers several advantages over others.
However, at the present time the total cost of a SSSC installation is higher
than the cost of other FACTS devices. Comparisons of two implemented control
strategies clearly show that the PWM based and phase controller have both
disadvantages and advantages, which makes the design process somewhat
complicated. The dc voltage pre-set value in PWM-based controllers has to be carefully
selected. As the modulation ratio lies between zero and one, the dc voltage
should not be lower than the maximum of the requested SSSC output phase voltage
in order to obtain proper control. On the other hand, if the dc side voltage is
too high, the rating of both the GTO valves and dc capacitor has to be
increased, which means higher installation costs. Not only that, a higher dc side
voltage means a lower amplitude modulation ratio, and the lower modulation
ratio results in higher harmonic distortion. Phase control allows the dc voltage
to change according to the power system conditions, which is clearly
advantageous, but it requires a more complicated controller and special and costly
series transformers. Also, Simulation results validate that Voltage and Power
Oscillation can be damped properly using of Synchronous Static Series Compensator
(SSSC).
REFERENCES:
[1] “Static Synchronous Compensator,” CIGRE,
Working group 14.19, 1998.
[2]
N. G. Hingorani and L. Gyugyi, Understanding FACTS, Concepts and Technology of
Flexible AC Transmission Systems. Piscataway, NJ: IEEE Press, 2000.
[3]
R. Mohan and R. K. Varma, Thyristor-Based FACTS Controllers for Electrical
Transmission Systems. Piscataway, NJ: IEEE Press, 2002.
[4]
L. Gyugyi, N. G. Hingorani, P. R. Nannery, and N. Tai “Advanced StaticVar
Compensator Using Gate Turn- Off Thyristors for Utility Applications”, CIGRE,
23– .203, August 26 September 1, 1990, France
[5]
J. Arrillaga, B. Barrett, N. A. Vovos “Thyristor Controlled Regulating
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