Harmonic Resonance Characteristic of Large-Scale PV Plant: Modelling, Analysis, and Engineering Case

Harmonic amplification and interaction of the PV plant which contains multiple parallel inverters influence the renewable power generation and operation seriously. In this article, the resonance mechanism and characteristics of a real large-scale PV plant are explored based on its plant-level circuit model. The component and system models are established first. The distribution rules of wideband resonance frequency from the perspective of the point of common coupling (PCC) and the inverter are respectively determined. Two different resonance bands excited by LCL filter and underground cable are further identified. At last, the practical case of harmonic resonance in the studied PV plant is investigated. Both the measured data and the simulation results support the analytical conclusions. This article combines the theoretical study with the engineering practice, which provides beneficial guidance on the resonance prevention.