A Novel Distributed Simulation Approach in Adaptive Distance Relaying

Abstract

In this paper, an adaptive distance relaying strategy based on the global network simulation (GNS) concept is presented. The GNS concept is actually a distributed simulation approach (DSA) for piecewise analysis of large-scale power grids using diakoptics and large change sensitivity (LCS) concepts. To set each utility's relays trip settings adaptively in each power system condition, detailed short circuit analysis is run in the GNS environment. It first updates the pre-fault voltage profile across utilities and then modifies their nodal ZBus in such a way to reflect the effect of the whole network in local fault studies performed by individual utilities; hence, presenting an accurate and secure federative approach on a geographically decomposed grid using local information and computational resources. A set of currently experienced rules in distance coordination is outlined and adaptive as well as conventional relay zone settings in each sub-network are calculated based on the selected rules. An efficient easy-to-implement algorithm to consider the effect of zero sequence mutual impedance among parallel lines is also presented and well integrated into the proposed adaptive approach in the GNS environment. The IEEE 14 bus test system and a real version of a large-scale grid with more than 2,600 buses are used to illustrate the characteristics of the proposed adaptive strategy in terms of security and dependability by comparison with conventional distance protection.