利用配电变压器获取行波信号

提出利用配电变压器传变行波，解决行波故障测距中线路末端信号不易获取的问题。分析了故障测距用行波信号对测量互感器的要求。建立了配电变压器行波传变特性分析等值电路，利用实际的变压器参数对其行波传变性能进行了研究，结果表明，配电变压器能够有效传变行波波头，满足行波故障测距要求。在此基础上进一步分析了三相配电变压器的行波传变特征及规律，分析发现，尽管中性点非有效接地系统单相接地故障后线路稳态线电压保持不变，但其故障暂态过程仍产生电压行波线模分量，并且它们可以有效传变到变压器低压侧，且只利用变压器低压侧的2个线电压就可以有效获取各种类型故障初始行波信号。现场试验结果证明了所述方法的正确性。

Traveling Waves Measurement with Distribution Transformers

A new method using distribution transformer to measure traveling waves is proposed to solve the problem of difficulty of catching traveling wave signals in feeders' terminal.The requirements of fault location signals to measurement transformers are analyzed.Equivalent circuit of transformer for analyzing transfer characteristic of traveling waves is built,and the transfer characteristic is studied using parameters of practical transformers.The results show that,distribution transformers can transfer traveling waves surge effectively and meet the needs of fault location based on traveling waves.The transfer characteristics and rules of three-phase distribution transformers are further investigated.The results show that although line- to-line voltage of stable state after single-phase to-earth fault in the neutral non-effective grounding system keeps invariable, transient process of the fault produces aerial mode component of traveling waves that can be transferred effectively to transformers' low-voltage side.Based on this,the idea is proposed that traveling waves generated by different type of faults can be measured effectively with only two line-to-line-voltage signals in transformers' low-voltage side.Experimental tests verify the feasibility and correctness of the proposed method.