Analysis of Relay Protection Problems in Micro-grid

Abstract

Abstract. The concepts of distributed generation and micro-grid were proposed. The influence of the micro-grid connected to the distribution network were analyzed from four dimensions, namely the distribution network planning, power quality, operation and control, and the load flow distribution. The protection scheme of the traditional distribution network was preferred. In this paper, the unwanted operation or failure to operation of three phase current protection, protection sensitivity change and lose selectivity were briefly summarized, which was caused by micro-grid interconnection. Several problems should be considered in the protection of micro-grid were pointed out, and its development trend was prospected.