An Adaptive Stabilizer for Thyristor Controlled Static Var Compensators for Power Systems

A static VAR systems play an important role as a stability aid for small signal and transient disturbances in an interconnected power system. Further the introduction of an adaptive stabilizer loop to its controller can significantly improve power system performance under a variety of abnormal situations such as 3-phase short-circuits, voltage collapse, load shedding, reactance switching, etc. This paper presents the analytical development of a new controller scheme for a static VAR system and presents detailed simulation results to highlight its effectiveness in comparison with a discrete PI stabilizer under a variety of operating conditions for power transmission systems. The adaptive stabilizer is suitable for microprocessor digital implementation as the numerical steps involved are minimal.