基于HHT及信号注入的配电网谐振与单相接地故障识别

Distinguish Resonance from Single-phase Earth Fault of Distribution Network based on the Method of HHT and Signal Injection

在中性点不接地系统中,单相接地故障与铁磁谐振时有发生,二者的外在表现特征非常相似,难以区分。本文分析了单相接地故障与铁磁谐振电压、电流特征,提出了利用HHT频率检测及信号注入相结合的识别方法。HHT频率检测法实现对分频和高频谐振故障的检测,利用H桥型逆变器注入电流信号实现对基频谐振故障的检测,避免了将铁磁谐振故障误判断为单相接地。仿真结果验证该方法能够有效识别谐振状态与单相接地故障。

In an isolated neutral point power system, single-phase grounding fault and ferroresonance happen frequently. It is ＂difficult to distinguish fault types because the external performance of them are similar. This paper analyzes the voltage and current characteristics of single-phase grounding fault and ferroresonance, then put forward the method of signal injection in combination with HHT frequency detection. The method of HHT achieve the distinction between low frequency and high frequency, then using the H bridge inverter to inject current signal to identify fundamental resonance fault, This way avoid the ferroresonance fault judgment error for single-phase grounding.This method is used to identify single-phase grounding fault from ferroresonance, verification by simulation data reveals that the measure is right and effective.