COORDINATED DESIGN OF STATIC VAR COMPENSATORS AND POWER SYSTEM STABILIZERS UNDER VARIOUS FAULTS

Abstract

Transient and low-frequency oscillations in power systems occur due to faults, load variations, and switching actions. As modern power systems operate close to their stability limits, damping these oscillations quickly and effectively has become a major challenge. Controllers like Power System Stabilizers (PSS) and Flexible AC Transmission System (FACTS) devices are widely applied to reduce such oscillations. Their performance, however, depends strongly on proper placement and accurate parameter tuning. A common problem is that controller settings are usually optimized for one specific operating condition. When system conditions change, their performance may significantly decrease, leading to serious oscillations. Hence, designing controllers that can perform well under different conditions is essential.

This study employs a Static VAr Compensator (SVC) whose parameters are tuned in coordination with Power System Stabilizers (PSS) to efficiently reduce after-fault oscillations. The SVC and PSSs controller gains are optimized to provide good damping not only for one type of fault but also for several possible fault scenarios. An enhanced Particle Swarm Optimization (PSO) algorithm is used to solve the optimization problem. The proposed method is tested on a two-machine system with PSS-equipped generators. Simulation results confirm that the robust tuning of the SVC controller improves system stability under various faults.