Responsibility Identification for Harmonic Instability in Grid-connected Inverter-Based Power System with Multi- Point of Common Coupling

Abstract

Harmonic instability problem, caused by the interaction between the inner control loops of inverters and the grid impendence, has drawn much attention in recent years. Some studies have been carried out to analyze the stability in systems with multi-paralleled grid-connected inverters and multi- point pf common coupling (multi-PCC). However, the identification of the most responsible unit for the harmonic instability in a power system with multi- PCC has not been fully discussed. An identification method is proposed in this paper based on the sum type impendence-based stability analysis method. Based on the stability analysis from the lower bus level to the higher bus level, the sequence of this proposed identification procedure is inverse, which is from the higher bus level to the lower bus level until to the unit that can not be divided for the instability. Simulations results verify the effectiveness of the proposed method.