基于自适应加速移频的PV孤岛检测与仿真

针对并网光伏(PV)系统的孤岛检测问题,提出一种复合负脉冲电流幅值干扰的自适应加速移频法。基于公共耦合点电压频率朝某个方向的持续变化次数,该方法对频率偏移正反馈系数进行自适应分段调节以加速频率偏移越限,如果变化次数超过12次,且频率仍未越限,则施加持续2个工频周期的负脉冲电流幅值干扰,触发欠压保护,从而检测出孤岛。Matlab仿真表明,与传统的AFD方法相比,该方法不仅对电网谐波影响小,而且孤岛检测盲区小,能有效在高速自动重合闸动作之前使光伏系统与电网解列,具有重要的应用价值。

A Novel Integrated Islanding Detection Method based on Adaptive Accelerating Frequency Drift

As grid photovoltaic (PV) system has the problem of island detection, a kind of adaptive accelerated frequency deviation method with complex negative pulse current amplitude interference is proposed. Based on the times of continuous changes towards certain direction of the voltage pressure in point of common coupling, this method makes adaptive segmented adjustment to the positive feedback coefficient of frequency deviation to accelerate the threshold-crossing of the frequency deviation; if the changes are more than 12 times and the frequency does not cross the threshold, then the negative pulse current amplitude interference lasting 2 power frequency periods will be applied to trigger the low-voltage protection and detect the island. Matlab simulation shows that, compared with the traditional AFD method, this method not only has small influence to power harmonics, but also has small non-detection zone for the island, so that it can disconnect the PV system and power grid before rapid automatic reclosure and has important application value.