Using a static VAr compensator to balance a distribution system

An algorithm for applying a fixed capacitor-thyristor-controlled reactor (FC-TCR) type of static VAr compensator (SVC) in a distribution system to dynamically balance such a system is introduced. With a newly developed individual phase control scheme, an SVC can reduce negative-sequence current caused by the load to improve power system balance. The control circuit is governed by a microcomputer, which replaces the traditional discrete load switching and makes the capability of rapid and dynamic balancing of the system possible. In addition, the power factor can be improved simultaneously by selecting an appropriate amount of capacitive/inductive compensation. This paper presents a mathematical model for computer simulation and control of a delta-connected SVC to achieve the purpose of negative-sequence reduction. Some computer simulation and scaled laboratory test results are discussed.