主动频移孤岛检测的抗干扰测频算法

Anti-interference frequency detection algorithm of active frequency shift islanding detection

针对并网光伏发电系统主动频移孤岛检测中,并网侧待测信号在过零点附近存在的噪声干扰,对过零测频法和锁相环测频法精度带来的不良影响,提出了一种具有噪声抑制功能的三角变换测频法。通过对最优检测点间隔进行估计和少数频率奇异点的剔除,即使并网光伏发电系统主动频移孤岛检测中并网侧待测信号受噪声干扰,带噪声抑制的三角变换测频法也能避免孤岛效应误判现象,提高了系统运行的可靠性。在MATLAB/Simulink下进行了建模和仿真,验证了该三角变换测频算法的正确性。

Aimed at the active frequency shift islanding detection of grid-connected PV generation system, the noise interference nearby zero crossing point of grid connected side signal to be measured brought adverse effects on the precision of zero-crossing measurement and PLL （phase-locked loop） frequency detection method, a triangle transformation frequency detection method with the function of noise suppression was proposed. Through optimal detction point interval evaluation and eliminating frequency singularity, the proposed method could avoid islanding misjudgement although grid connected side signal to be measured is interfered by the noise, system operation reliability was improved. The simulation model of system was established, which verified the the correctness of the method.