Development of the high accuracy Impedance Type Fault Locator using a Mode Transformation

The authors have developed an innovative FL (Fault Locator) System, which takes the 3-phase unbalance into consideration by simulation of a power transmission line with the distributed constant circuit and use of the theory of mode transformation. The system developed by the authors automatically reads the waveform data of voltage and current from the fault recorder which is time-synchronized to the GPS (Global Positioning System) and measures distance to the fault point using the above-mentioned data and power transmission system data which are set in advance. The authors carried out field tests of the FL System developed by the authors on fourteen lines of the 66kV power transmission system of TEPCO (Tokyo Electric Power Company) and obtained good results that showed a mean error of 0.43 [km]. This paper presents these results.