A New Theory for Locating Line Fault in Power System: Theoretical Part

Abstract

This paper proposes a theory for locating line fault based on the basic principle of time reversal. The proof has five steps. First, the theoretical voltage and current at the ends of the line are calculated based on the transmission equation of the line in the additional network after line fault occurred. Second, the loss and lossless mirror line are established according to the parameters of the actual line. Third, the values of the implemented sources at the ends of the mirror line are calculated based on the conjugate complex of the theoretical values of voltage and current in the first step. Fourth, the RMS value of the fault current is calculated by assuming that fault occurs at every point of the mirror line. Finally, we should identify that there is only one peak value among all the RMS values and it exists at the actual fault location. In this paper, the fault location theory is proved with and without reflected waves by using the transmission equation of a single line. It is further proved in the mixed line that consists of two lines of different parameters considering the reflections.