Fault indicators in transmission and distribution systems

Fault location techniques can be classified under three categories: (1) those based on fundamental frequency currents and voltages; (2) those based on travelling wave and high frequency components; and (3) those based on knowledge-based approaches. Fault indicators can be installed either in substation or on pole/tower along the transmission line. This paper reviews the fault indicator applications both in transmission and distribution systems. Principles, merits and demerits of each fault location technique are discussed. Finally, this paper suggests an advanced fault indicator based on fault generated high frequency noise signal (FI-HF), which is mounted between earth wire and tower. Fault generated high frequency noise signal is captured by a special designed "earth trap" and stack tuner.