弱电网下光伏发电系统谐振机理研究

A Research on the Resonance Mechanism of the PV Generation System in Weak Grids

光伏发电系统一般都要通过较长的输电线路接入电网,可能会有电网阻抗较高,短路容量较低的情况出现。这些条件会引起光伏并网变流器的系统谐振。围绕弱电网条件下的并网变流器谐振问题展开研究,通过光伏发电系统的数学模型,对弱电网条件引起并网变流器特定次谐波振荡的机理进行分析,研究了影响系统发生谐振的主要因素,并通过仿真验证了理论分析的正确性。

As the PV generation system is normally connected to the power grid over a long transmission line, grid impedance might remain high and short circuit capacity might be low. That would possibly result in system resonance of the PV grid connection inverter. This paper studies resonance of the grid connection inverter under the condition of weak power grid. By using a mathematical model of the PV generation system, it analyzes the mechanism for specific sub-harmonic oscillations of the grid connection inverter under weak grid condition. Major factors causing system resonance is discussed, and the correctness of theoretical analysis is verified through simulation.