METHOD OF DETECTING GROUNDING ACCIDENT DIVISION OF UNDERGROUND POWER TRANSMISSION LINE

PURPOSE:To prevent the influence due to the characteristic nonlinear distortion of an electric-photo converter by transmitting the grounding currents, which are caught with the zero-phase current transformers being arranged in plural numbers in an underground power transmission line, to a substation or the like as an optical signal where the width is constant and the number of pulses is proportioned to the grounding current. CONSTITUTION:Pluralities of zero-phase current transformers and transmitters are arranged apart at different positions on an underground cable (three-phase transmission and distribution line). And a signal is transmitted from each by an optical fiber, and the phase difference between these signals is detected. Hereby, it comes that one can know the direction of the grounding current and which division the grounding accident has occurred in.