The determination of faults on transmission lines by using fuzzy logic method

One of the most important problems in power systems is faults. In the first of the faults, the short-circuit faults on transmission lines take the lead. A short-circuit fault occurs on any part of the transmission line, some damaged situations can be occur for elements of the power system. Decreasing the level of damage occurred by these faults, the determination of fault type is needed in very short period of time. In this work, a fuzzy-based intelligent system that thinks and decides like a human has been used for determining of the fault type.In this thesis, main fault types occur on transmissionlines: single phase to ground fault, two phase to ground fault, phase to phase fault and three phase fault have been investigated by regarding prefault and fault current components.The inputs of fuzzy logic have been consisted by using prefault and fault currents and the outputs have been obtained by a rule table using Mamdani type fuzzy system taking account of experiences of the experts and modeled systems. Type of the fault has been determined by classifying acquired outputs.Matlab/Simulik has been used to consist of the fuzzy logic system and suitable results have been obtained using sample calculations for fault conditions.Key Words: Energy Transmission Lines, Short-Circuit Fault, Fuzzy Logic.