Analysis of Fault Location Methods for HVDC Transmission Systems Using Overhead Lines and Cables

Abstract:
In this paper, fault location methods for HVDC (high-voltage direct current) transmission systems based on the detection of travelling waves are presented. Two fault location methods are compared: the “one-end method”, which requires voltage or current signals measured at only one end of the transmission link and the “two-end method” that requires signals from both ends. The discrete wavelet transformation as well as the unprocessed output of a modelled Rogowski coil current transformer were used to precisely determine travelling wave arrival times. Simulations were performed using PSCAD software for 700 km frequency dependent transmission link models in three different configurations: overhead line (OHL), underground cable and a hybrid transmission link consisting of overhead lines and underground cables. The hybrid transmission links will be implemented in German transmission network and therefore especially the accurate identification of faulted sections (overhead line or cable) is of high interest and the key finding of this study. Simulation studies showed that the two-end method is superior in terms of accuracy and its applicability to hybrid transmission links, whereas the one-end method is a very economical solution only suitable for homogenous overhead lines.