Relay Coordination of over Current Relay in Presence of DG System using FCL

In the Power System presence of Distributed generation (DG) is one of attractive phenomena. With the presence of DG units in distribution system, its function would generally be changed and it would variously be affected by DGs. When DGs are introduced into the power system, the value and direction of both system's power flow in normal operation and short circuit current under fault condition are changed results the disturbance to relay coordination. In this, GA-NLP approach is presented to solve the directional over current relay coordination problem, which arises from installing DG in distribution system. This approach involves the implementation of Fault Current Limiter (FCL) to limit the DG fault current. In this thesis, simulation of 3-bus and 9-bus system is implemented in ETAP software. The optimum value of time multiplier setting (TMS) and plug setting (PS) are found by using MATLAB Optimization toolbox.