一种基于锁相角扰动的主动式反孤岛策略

An active anti-island strategy based on phase-locked angle perturbation

为减小并网电流畸变率,提高孤岛检测的响应速度,以满足不同类型负载的要求,提出一种基于锁相角扰动的主动式反孤岛策略。通过对参考电流锁相角引入一个微小的随正弦规律变化的扰动,使得参考电流到达峰值的时间向左或向右偏移,同时其频率又不受影响,由于逆变器输出电流是跟随参考电流的变化而变化,因而在主电网断电时,公共点电压过峰值的时间会有一个小角度的偏移,当偏移程度超过设定阈值范围,逆变器断开,停止向主电网供电。在PSCAD中搭建了单相光伏逆变器孤岛检测仿真模型,对多种类型的负载进行了仿真,结果表明,该方法具有对电网产生的谐波小、无检测盲区、算法简单易实现等优点。

To reduce the grid current distortion, improve the response speed of islanding detection and be able to fit different types of loads, an active anti-islanding strategy based on phase-locked angle disturbance is proposed. By introducing a slight sinusoidal variation disturbance into phase-locked angle, so that the reference current peak time will shift to the left or right, while frequency is not affected. Since the inverter output current will follow the change of the reference current, so when the grid is powered off, the common point overvoltage peak times will have a small angle shift. If the shift exceeds a set threshold range, inverter becomes disconnected and stops supplying power to the main power grid. A single-phase photovoltaic inverter islanding detection simulation model is built in the simulation platform of and simulations of different types of loads are conducted. The results show that this method has many advantages, such as small harmonics on the grid, no blind spot detection,algorithm is simple and easy to achieve, etc.