Generalized distance-based protection design for DG integrated MV radial distribution networks — Part I: Guidelines

Abstract

The critical advantages of distance protection render this protection principle a promising option for distribution systems, especially in light of integrating distributed generation. The first part of this two-paper series proposes complete guidelines for designing directly applicable and economically feasible distance protection schemes for medium-voltage radial distribution systems with distributed generation. These guidelines intend to take account of distributed generation, since they are designed to deal with its effect in terms of both directionality (bi-directional flow of short-circuit current) and protection dependability (intermediate infeed effect). Moreover, they are designed to address the concurrent effect of any other critical factor related to distance relay operation (e.g. fault resistance and zero-sequence compensation), as well as the coordination of distance relays with lateral protection means. The procedure is systematic and independent of specific distributed generation conditions, while, it has to be performed only once for a particular distribution system. Economic feasibility of the designed protection scheme is preserved, as it is intended to install the minimum number of distance relays, without using communication means. Furthermore, simplicity and direct applicability is ensured, as the proposed guidelines are implementable using existing distance relay technology.