Malfunction detector for static var controllers

Abstract

A static VAR generator for providing reactive compensation incorporating a malfunction detector. The static VAR generator comprises a reactance which is linearly responsive to a first linearized control signal and produces an output signal proportional to the reactive compensation which provides a feedback signal. A director control uses the feedback signal and an adjustable reference signal to provide the first linearized control signal based on the difference between the reference and feedback signals. A tracker controller provides a second linearized control signal based on the reference and feedback signals. The second control signal is compensated by an equalizer that determines the difference between the first and second control signals. The compensation counters the difference between the first and second control signals caused by the offset and component tolerances in the two controllers and makes the second control signal substantially equal to and track the first control signal. A first comparator conpares the compensated second control signal with the first control signal. Whenever these two control signals are not substantially equal, a fault has occurred in one of the two controllers. A second comparator compares the first control signal with the output signal. Whenever these two signals are not substantially equal, a fault has occurred in the generator. In an alternate embodiment an additional tracker control, comparators and default decoder provide a 2 out of 3 polling system for indicating when one of the three controllers is malfunctioning.