Voltage profile correction of a load bus by static reactive power compensators with quantization controllers

Abstract

The voltage profile of a load bus is corrected by a static reactive power (VAR) compensator (SVC), which is constructed from thyristor controlled reactors and fixed capacitors. The SVC can provide reactive power compensation to the load bus and stabilize the load bus voltage. The conduction of the reactors is controlled by a 12-pulse thyristor bridge. A digital quantization controller is synthesized by the software program on a Motorola M68HC11EVM single-chip microprocessor board. At each sampling instant, a quantized incremental value for the firing angle of the thyristor is determined from the error between the load bus voltage and the reference voltage. Implementation test results following a load change show that the load bus voltage can always be maintained at almost a fixed value by the SVC. The dynamic response of the load bus voltage is improved.