METHOD FOR EVALUATING GROUNDING FAULT POINT OF THREE- PHASE POWER TRANSMISSION DISTRIBUTION LINE

摘要

PURPOSE:To realize the titled method wherein the influence of the variation in the impedance of a fault point is reduced and the reception of the influence of distribution capacitance is reduced even if the frequency of a testing power source is taken high so as to be capable of simply performing the application of AC voltage for evaluation to a transmission distribution line, by estimating the distance from the measuring end of the grounding fault point on the basis of first and second measured values by respectively providing current source circuits to both ends of the section of the transmission distribution line to be subjected to the evaluation of the grounding fault point. CONSTITUTION:When grounding fault is generated at the trouble point F of a transmission distribution line L2, the grounding detecting apparatus not shown in the drawing detects the generation of the fault and, by this detection, grounding phase discriminating apparatuses 13, 23 are operated to discriminate that the transmission distribution line L2 is a fault line while the contacts of switches 14, 24 and switches 16, 26 are selectively closed to respectively connect AC transformers 12, 22 and current transformers 15, 25 corresponding to the accident line to current source circuits 1, 2. In this state, a measuring instrument 30 measures the specific electric value, for example, the reactive power in the current source circuit 1. This measured value is a first measured value. At the same time, the zero phase voltage V0 of a three-phase transmission distribution line is measured by a means not shown in the drawing.