Analysis on the Equivalent Circuit of a Kind of Zero-Residual-Current Arc Suppression Coil and Distribution Network

Abstract

The existent arc suppression coil (ASC) can only realise the compensation for the reactive component of the fundamental capacitive current. But for the active and harmonic ones, they are powerless. Therefore, it is necessary to study on the so-called zero-residual-current ASC". In this paper, the authors first introduce the structure of a kind of zero-residual-current ASC, namely, three phases and five columns ASC with double secondary windings. Then the authors analyse in detail its equivalent circuit and the equivalent circuit of the distribution network in which this kind of zero-residual-current ASC is used during the normal operation and the single-phase-to-ground fault respectively. Based on SABER and MATLAB, the simulation models of distribution network and TPFCASC with double secondary windings are given. From the waveforms of simulation experiments, we can see clearly that the so-called zero residual current is realised, which proves the theoretical analysis. It should be noted that the equivalent circuit of this zero-residual-current ASC is different from that of common power transformer. Owing to the air gaps in the iron cores, the exciting reactance of this zero-residual-current ASC is much smaller than that of common power transformer. Thus, only the exciting reactance is used as equivalent reactance in its equivalent circuit but without considering the leakage reactance of each winding.