Travelling wave fault location on hybrid power lines

Detection and location of faults on power systems have great importance in term of being able to clear faults in a short time and provide more available service to customers. Since sensitive determination of fault location is necessary, it is required to measure the arrival time of the travelling waves accurately and to use corresponding propagation velocity of the cable. However, when a fault location scheme is utilized for this purpose, which uses the velocity of the propagation as a parameter during analysis, changing parameters of the cable over its age, such as relative permittivity, introduce large errors in determination of the fault locations. On the other hand, hybrid systems including cable and overhead lines makes the detection of fault location more difficult. Therefore, in order to have precise fault localization, the successful analysis should not use the velocity of propagation especially for the aged cables. This paper describes the use of wavelet analysis for identifying fault location on power lines without using the velocity of propagation. Extensive simulation work has been done in order to check the effectiveness of the proposed scheme based on wavelet analysis. Different fault scenarios have been utilized on a given power system model. The obtained results indicate that the proposed scheme is effective and able to locate the points of faults with reasonable accuracy. This scheme can also be further used for the travelling wave protection on power systems to provide fast and accurate fault clearance.