NEGATIVE-PHASE-SEQUENCE REDUCTION WITH ADJACENT STATIC REACTIVE-POWER COMPENSATORS

Static reactive-power (VAr) compensators (SVCs) can be used to reduce negative-phase-sequence (NPS) voltages by balancing, for example, phase-to-phase-connected loads. In such cases, they are effective until their controlled elements, usually thyristor-controlled reactors, reach their operating limits. Once this happens, NPS currents flow in the system and produce NPS voltages. If several load-balancing SVCs are located in close electrical proximity, adjacent load-balancing SVCs are able to absorb some of this uncompensated NPS current, reducing the overall NPS-voltage profile. The mutual support thus provided should be considered when designing the ranges of such load-balancing SVCs. The paper describes how to quantify the mutual support in a system with multiple load-balancing SVCs.