Comparison of Resistive and Active SFCL for Mitigation of Fault Currents and Voltages at Distribution Level
Over the past few decades, the renewable energy based Distributed Generation (DG) has experienced dramatic development due to numerous reasons, including environmental concerns and in preparation for an expected shortage of traditional fossil energy. DGs are generally small generator units installed close to the power consumers and involve the S Application of new energy conversion technologies, e.g. inverter-based grid connections. DGs under regular load conditions generally have the benefit
... have the benefit of reducing power loss in the distribution system, since they are locally substituting energy delivery through the distribution network with local delivery. But despite this favorable effect, DGs also contribute fault current in case of a network fault, potentially adversely affecting the network protection system. In a radial distribution network, the inverse time over-current relays are usually used for fault protection. As the introduction of DG into an existing distribution network inevitably increases the level of fault current with its fault current contribution, DG can ultimately disturb the original over-current relay coordination. In this voltage compensation type active SFCL is proposed. The active SFCL's control strategy and its influence on relay protection is described. Taking the active SFCL as an evaluation object, its effects on the fault current and overvoltage in a distribution network with multiple DG units are studied. In view of the changes in the locations of the DG units connected into the distribution system, the DG units' injection capacities and the fault positions, the current limiting and overvoltage-suppressing characteristics of the active SFCL are investigated in detail. The proposed concept in implemented with In extension by comparing the resistive and active SFCL for mitigation of fault currents and over voltages by using MATLAB/SIMULATION software and the results are verified.