Solutions to Design and Coordination Relays for Protection Challenges of Distribution Network with DG

In this paper in order to ensure that protection of the system remains reliable even after introduction of DG is studied key Protection Challenges of the DN with DG and established rules for the design and coordination of protective relays in a power system. Such as Differential Protection Schemes, A Balanced Combination of Different Types of DG Units for Grid Connection, Inverter Controller Design, Voltage-Based Detection Techniques, Adaptive Protection Schemes, Protection Based on Symmetrical and Differential Current Components, for describes a case study of a typical DN with DG. Various protection schemes for micro grids, both in grid-connected and islanded mode of operation, are explored. The techniques and strategies, such as analysis of current using digital signal processing for characteristic signatures of faults, development of a real-time fault location technique having the capability to determine the exact fault location in all situations, use of impedance methods, zero sequence current and/or voltage detection-based relaying, and differential methods using current and voltage parameters, have the potential for developing more robust protection schemes to cope with the new challenges. KEYWORD: Microgrid, Protection, Fault Current Level Modification, Sympathetic Tripping, Blinding of Protection, Reduction in Reach of Impedance Relays