Coordinated Robust Damping Control for Hybrid SVC/SSSC to Enhance Power System Stability in Large-Scale Systems

The restoration of stability is major problem in power transmission system after the disturbance. Flexible AC transmission system (FACTS) devices have the ability to restore the stability of the system by manipulating the transmission parameters. The combination of FACTS devices is more effective than single device used alone. This article investigates a coordinated control strategy involving static VAR compensator (SVC) and static synchronous series compensator (SSSC). The SSSC is used to lower the line's equivalent impedance and improve its active power transfer capabilities. To maintain bus voltage magnitude, a SVC is used for shunt compensation. Utilizing identical signal input tracking enables the operation of a device depending on the compensation provided by the other device. The efficacy of the proposed scheme is demonstrated by applying it to a tie line of two area 4-machine 11-bus Kundur test system and observing the system variables after a major fault is created on another tie line. The improvement achieved is highlighted by comparing the behavior with that of the uncompensated and conventionally compensated system. The simulation study is carried out in MATLAB Simulink which further supported by the real time simulation in Opal RT digital simulator. Also, cost function analysis shows that the proposed scheme is cost effective compared to other conventional schemes.