New Principle to Identify the Second Reverse Traveling Wave Generated by Single-phase-to-ground Fault

Identification of traveling wave reflected by fault point or by bus at remote end is the core of traveling wave based distance protection and fault location based on single-end traveling wave. However, when single-phase-to-ground fault occurs in the three-phase transmission lines, the polarity of traveling waves is affected by the configuration of buses at both ends of protected lines and traveling waves obtained at measurement. In this case, it is difficult to identify if the second reverse traveling wave is reflected from fault point or the bus at the remote end. This paper presents a new principle based on the polarity relation of zero module and line module of the second reverse direction traveling waves, which is independent of the configuration of buses. If the relation of zero module and line module is the same, the traveling wave is reflected from the fault point; otherwise, from the bus at the remote end. EMTP simulation shows that the principle is correct and reliable.