Study on travelling waves transform characteristics of potential transformers

A new method using potential transformers to catch travelling waves is proposed to solve the problem of catching travelling wave signals difficultly in terminal of feeder. Travelling waves transform characteristic of potential transformers is studied. The paper briefly analyses basic characteristics of travelling waves generated by fault and confirms its selected frequency band. Then the demands to measurement potential transformers are presented when the potential transformers are used to catch travelling waves. Potential transformers equivalent circuit for analyzing travelling waves transform characteristic is built, meanwhile, the characteristics are computed and analyzed using practical potential transformers parameters. The results show that, for transient travelling wave signals, potential transformers have much shorter rise-time and higher cut-off frequency, so they can transform travelling waves surge effectively and meet the needs of fault location based on travelling waves. Experimental test verify the feasibility and correctness of the proposed method.