Study on combined system of hybrid power filter and controlled reactor

This paper presents a combined system of hybrid power filter and controlled reactors for compensating the reactive power and harmonic current under the condition of three-phase four-wire system. A delta-connected thyristor controlled reactor is used to eliminate fundamental negative-sequence current, and a Y-connected thyristor controlled reactor is used to compensate fundamental zero-sequence current. The instantaneous reactive power theory is modified for three-phase four-wire system. Adopted this theory, negative-sequence current and zero-sequence current can be detected accurately and rapidly.