光伏并网系统中的新型孤岛检测方法

摘要

The island occurrence in photovoltaic (PV) grid-connected system will not only damage the equipments, but also endanger the life safety of people. The traditional periodic current magnitude variation (PC-MV) detection method requires adding alternate active disturbance to draw the correlation factor, which reduces the detection speed and has a direct impact on the quality of electric power grid. In order to solve the above problem, a kind of novel islanding detection method is proposed based on the current disturbance. This method detects the output voltage and current disturbance of the inverter, calculates the correlation factor, and then compares the correlation factors with threshold value to judge whether the island effect occurs. In this paper, 3kW photovoltaic inverter is used to both simulation and experiments. The results verify the feasibility of the method, which has the short testing time and a certain application value.%光伏并网系统中产生孤岛时,不仅对设备造成破坏,而且危及维修人员的安全.传统的定期电流幅值变化(PCMV)检测方法需要加入备用的主动扰动才能得出相关因子Cf,降低了检测的速度,直接影响了并网电能质量,针对上述问题,提出一种新型的基于电流扰动的孤岛检测方法.此方法通过检测逆变器输出电压Vinv和电流扰动率K计算出相关因子Cf,比较Cf与阈值来判断是否发生了孤岛效应.对3 kW光伏逆变器进行仿真研究和实验,仿真和实验结果验证了该方法的可行性,检测时间短,具有一定的工程应用价值.