교류 AT 급전계통에서의 전차선 전류비를 이용한 고장점 표정 기법에 관한 연구

초록

In AC feeding system, the fault location is calculated by using ratio of current absorbed in the neutral point of AT(Automatic Transformer). In this way, however, an estimation error can happen due to the effects on current flowing into other lines. In addition, for measuring currents in the neutral point of AT, other measuring devices and communication equipments are additionally required. And it incurs additional expenses. In order to solve the demerits, this paper suggests a novel technique using the ratio of catenary current. The method of catenary current ratio uses existing protective relays and measures catenary current. With the measured values, we can calculate the current ratio of catenary and determine fault location. In this paper, we modeled AC feeding system using PSCAD/EMTDC as an analysis program of power system and simulated a variety of fault cases. Through the simulated results, we derived the correlation between current ratio and fault location. Using this technique, additional equipments and expenses can be reduced. Besides, fault location can be determined more correctly.