Novel active filter system composed of inverter bypass circuit for suppression of harmonic resonance

Abstract

We have developed a novel harmonic compensation system consisting of shunt LC filters on the load side, a step-down transformer on the receiving end, and a small-capacity active filter with one end connected to the secondary winding of the transformer and the other to the load bus. The active filter which constitutes the bypass circuit for the main service transformer is current-controlled to give adequate damping of the harmonic resonance caused by the inductance behind the load bus, especially at lower harmonic frequencies. We have installed this new compensation system in combination with a TCR-type SVC and shunt LC filters at the Yamanashi Maglev Test Line. We present an outline of the reactive power and harmonic current compensation systems, and harmonic resonance test results which show satisfactory performance of the active filter. © 1999 Scripta Technica, Electr Eng Jpn, 129(1): 82–90, 1999