一种新颖的周期电流扰动孤岛检测方法

A Novel Periodic Current Injection for Islanding Detection Method of Grid-connected Photovoltaic Inverter

当分布式发电系统的输出功率与负载消耗功率匹配,且负载谐振频率等于电网频率时,即使孤岛发生,此时公共耦合点(PCC)的电压和频率仍保持不变,将一直处于非检测区内。深入研究了一种新的电流扰动法,并对其进行改进,提出一种新颖的周期电流扰动检测方法。新算法在部分周期电流波形中注入扰动,改变了部分电流的幅值。引入的扰动会导致PCC电压在正负半周期的幅值呈现高低变化,通过连续观察正负半周期电压幅值是否周期性呈现高低交替变化来识别孤岛现象。经过理论分析和Simulink仿真验证,该方法可以准确地识别非检测区的孤岛效应,同时对电能质量影响小。

When the demand power of the local load is matched with the power generated by the distributed power generation system, and the resonance frequency equals to the frequency of the utility, the amplitude of the voltage and frequency at the point of common coupling（PCC） isn＇t change in non-detection zone.This paper bases on a current injection for islanding detection method, presents a novel method.The proposed method injects a different current distortion into current waveform to changing part of the current amplitude.The disturbance modulates the amplitude of the voltage at the PCC to drift high or low.The islanding is detected by judging whether the amplitude at the PCC change as the rule.The proposed algorithm is validated by simulation does in Matlab platform. The results verify that the proposed method can identify the islanding in on-detection zone very well, and has less impact on power quality.