퍼지추론시스템 기반 지중송전계통 보호용 거리계전 알고리즘 개발

If the fault occurs on the underground power cable systems, the fault current on the sheath has an influence on all sections of cable because it's returned through earth at the directly grounded point and operation point of SVL(Sheath Voltage Limiter) on each insulated joint box. Therefore, the earth resistance and the operation of SVL have an effect on the zero-sequence current, and then the impedance between relaying point and fault point is increased. That causes the overreach of distance relay. For these reasons, the distance relay algorithm for protecting an underground power cable systems hasn't been developed till now. In this paper, new distance relay algorithm is developed for protecting a underground power cable system using fuzzy inference system which is the one of ACI(Advanced Computational Intelligence) techniques. This algorithm is verified by EMTP simulation of real power cable system, and proves to effectively advance the errors