基于频率-功率因数角组合判据的新型孤岛检测法

为解决传统的孤岛检测方法难以兼顾电能质量和检测效率的问题,在综合分析孤岛前后孤岛内公共耦合点的频率和功率因数角之间变化关系的基础上,推导出了两者的定量关系,提出了一种基于组合判据的新型孤岛检测方法。该方法将频率变化与功率因数角的变化相结合,提高了判据的灵敏性,并且通过延时提高了新方法的可靠性。仿真证明,相对于传统的被动式孤岛检测法,在不同性质的本地负荷下,新方法具有较高的检测效率,且在系统发生扰动时,有较高的鲁棒性。新方法是一种被动法,在系统并网运行时不会影响电能质量。

A new anti-islanding detecting method based on combined criterion of frequency and power-factor angle

In order to solve the problem that the traditional methods are unable to ensure both power quality and the efficiency of detection, a new anti-islanding detection method is proposed based on the analysis of the relationship between the frequency and power-factor angle when islanding happens. The new method combines the varieties of frequency and the power-factor angle when islanding happens, which improves the sensibility of the criterion and enhances the reliability by delaying. Simulation proves that compared to the traditional method, the new method could detect islanding efficiently without affecting the power quality when the DG system is connected to the grid.