计及谐波影响的不对称系统基波序分量快速检测

Fast detection of fundamental components for unbalanced system considering harmonic distortion

基于延时构造正交信号的时域瞬时对称分量变换被广泛应用于计算三相不对称系统的正序与负序分量。推导了延时构造基波正交信号所导致的谐波变化,建立了含有谐波的不对称电压经时域瞬时对称分量变换后的序分量表达式。基于延时系数与谐波阶次之间的数值关系,详细研究了谐波在电压序分量中的分布规律。综合考虑正交信号延时与Park变换后的滤波时间,给出了利用时域瞬时对称分量变换快速准确提取谐波畸变不对称系统基波正序分量与负序分量的正交信号最佳延时构造方法。仿真与实验证明了理论分析的正确性。

The ISC(Instantaneous Symmetrical Components)transformation based on time domain OSG(Ortho-gonal Signal Generation)by using time delay is widely used to extract the positive-and negative-sequence components of three-phase unbalanced system.The harmonic changes caused by time delay based OSG of fundamental signal are derived,and the analytical expressions of the positive-and negative-sequence components of unbalanced voltage obtained by ISC transformation are established.The distribution regulation of har-monics in sequence component of voltage is provided in detail by using the numerical relationship between time delay parameter and harmonic order.The optimal time delay method based OSG for ISC transformation to fast and accurately extract the fundamental positive-and negative-sequence components of unbalanced system is given by taking the OSG time delay and the filtering time of moving average filter after Park transformation into account.Simulative and experimental results prove the correctness of theoretical analysis.