International Journal of Engineering Research in Electrical and Electronic Engineering (IJEREEE)

Optimal Coordination of Dual Setting Directional Overcurrent Relays for Microgrid Protection

Author : Srinivas STP ¹ K. Shanti Swarup ²

Date of Publication :7th March 2017

Abstract: Utilization of Renewable Energy Resources (RES) at the consumer neighbourhood resulted in self reliable power system operation.Distributed Generation (DG) supported distribution systems can be operated intact with the main grid or can be operated independently. Such a system can be termed as a microgrid. The feasibility of microgrid operation make its protection more complex. One of the profound challenges faced by the power engineers in designing a working microgrid system is relay coordination. Directional overcurrent relays (DOCRs) are economical and feasible protective means in subtransmission and meshed distribution system.However, in the microgrid scenario, the relay coordination problem becomes a complex issue due to varied system operation viz. grid connected and islanded modes. This paper suggests a solution to relay coordination problem in microgrids by using dual setting overcurrent relays. Unlike conventional DOCRs which rely on two settings TMS and PS only in forward direction, dual setting DOCRs operate in accordance to four relay setting of TMS and PS both in forward and reverse directions, thus provide more flexible relay settings. This work presents such a problem which is formulated as a nonlinear constrained optimization problem and solved using hybrid GANLP approach.

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