Norm Criteria in the Electromagnetic Time Reversal Technique for Fault Location in Transmission Lines

This paper investigates the use of the norm criteria in the electromagnetic time reversal (EMTR) technique to locate faults in transmission lines. The energy root criterion and amplitude peak criterion, derived from 2-norm and ∞-norm, are considered and discussed contrastively. It is shown that both considered norm criteria can effectively be used in an EMTR method to locate faults. The ∞-norm originates from temporal and spatial variation of norm quantity of voltage/current wave propagation in the EMTR process. It is proven that the ∞-norm criterion makes use of the EMTR refocusing property of voltage/current waves propagating along transmission lines. In the extremely noisy circumstances, the ∞-norm criterion shows better robustness against noise compared to the 2-norm. It can locate the fault accurately even when the time-domain features of a strongly interfered signal cannot be identified. To validate the performance of the proposed criteria, two experimental tests on a reduced-scale network composed of coaxial cables and a real power grid are performed. The fault position is located accurately by the two criteria using one-terminal measurement data. It is suggested that the two criteria can be used complementarily to enhance the fault location efficiency.