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The arcing fault has a high probability of occurence on a HV transmission line. To date, the transient resistance is always assumed as a linear constant resistance in most of the locating algorithms. On the basis of the previous achievements in arc modeling, the paper describes an ideal voltage-current transform characteristic relationship and its equivalent circuit representing for long arc, and then presents a novel short time-window method for locating arcing faults on coupled double-circuit HV transmission line using one-terminal voltage and current samples. The method proposed has the advantages as follows: (1) arcing discharge is taken into account; (2) CT saturation is considered for a short time-window, which can be chosen from the initial time of a fault, less than half period; and (3) far-terminal equivalent impedance is not required. Moreover, the requirement of high accuracy to fault location is ensured by using the least error squares method. A lot of digital simulation shows that the scheme is feasible. The method has been applied to Kunming electric network.

The current travelling wave is utilized to detect the fault position in the transmission lines in this paper. How to identify the incident travelling waves and reflected ones from the fault point when noises exist is discussed and resolved. A fault position relay based on current travelling waves and wavelets theory is designed. The relay's principle is mainly on wavelet theory and modulus maxima of the wavelet transform. By analyzing the distribution of the modulus maxima, different components in the current travelling waves can be distinguished and then the incident and reflected travelling waves are identified and finally useless components are filtered. The incident and reflected travelling wave's time difference arrival time difference indicates the fault position. An EMTP simulation example is illustrated. The relay is been proved correct and effective.

The authors proposed and implemented a totally new solution for test and evaluation of relay performance. The newly developed testing platform can produce 8-channel synchronous high frequency transient voltage and current output to drive a protective relay and fault locator. It can also receive 8-channel response for recording and measuring operating performance and operating parameters of the relay.