光伏并网逆变器的间歇性频率扰动正反馈孤岛检测方法

传统无源孤岛检测方法存在检测盲区，有源孤岛检测方法虽然可以减小或消除检测盲区，但在一定程度上会影响电能质量。为了消除检测盲区并最大程度地减小其对电能质量的影响，文章提出了一种间歇性频率扰动正反馈孤岛检测方法。该方法每隔1s引入持续1个工频周期的微小频率扰动用于打破孤岛后可能发生的功率平衡状态。由于该扰动间隔时间长，持续时间短，因此对电能质量影响极小。根据IEEE Std.929-2000规定的最差情况进行孤岛测试仿真研究，仿真结果表明，文中的方法具有响应快速、无检测盲区、对电能质量影响极小等优点。

Islanding Detection for Photovoltaic Grid-Connected Inverters Based on Intermittent Frequency Disturbance

Traditional passive islanding detection methods have a defect of non-detection zone (NDZ). Although this defect can be reduced or eliminated by active islanding detection methods, however, active methods often have negative effect on power quality. In order to eliminate NDZ and alleviate its impact on power quality as possible, a positive feedback islanding detection method based on intermittent frequency disturbance is proposed, that is, every other one second a tiny frequency disturbance whose lasting time equals to one period of power frequency is led in to break down probable power balance under islanding state. Due to long interval time and short duration of this tiny frequency disturbance, its impact on power quality is slight. According to the worst condition given by IEEE Std. 929-2000, simulative research on islanding test is performed and simulation results show that the proposed method possesses such advantages as fast response, no NDZ and slight impact on power quality.