Research on harmonic and overvoltage of photovoltaic power plant electricity energy collection system based on passive network model

Abstract

In large‐scale photovoltaic (PV) power plant, the output power of each grid‐connected inverter is collected by electricity energy collection system and then is put into the grid. Previous studies have demonstrated that the harmonic problem may occur when PV inverters run in parallel even if all the PV inverters output power do individually satisfy the standards. Considering the electricity energy collection system, this study builds the model of harmonic transfer passive network for the typical topological structure of large‐scale grid‐connected PV power plant, and study the generating mechanism of harmonic and overvoltage. The harmonic power flow of a given calculation example is calculated by using node matrix method and the harmonic voltage magnification of each node is got. The point of common coupling is chosen as the study object. In this study, the impacts of cable parameters, the equivalent impedance of power grid and operation mode of PV power plant on the voltage magnification properties of the transfer network are analysed.