Adaptive Protection Method of Distribution Networks Using the Sensitivity Analysis for Changed Network Topologies Based on Base Network Topology

This paper proposes an adaptive protection method using sensitivity analysis that examines the effect of changed network topologies (CNTs) on the operation time of protective devices (PDs) for a base network topology (BNT) in a distribution network. In this study, BNT refers to the topological structure of the distribution network maintained over the long-term, whereas CNT is the changed structure maintained for a relatively short term for field workings, fault restoration, or real-time reconfiguration. The main purpose is to consider the PD’s operating speed and the number of controls for changing the settings and to calculate the optimal setting values for two terms while including the CNT in the BNT over a long duration. For this purpose, we used two approaches: First, a sensitivity index, defined as the increase in the operation time of the PD for the BNT when each CNT is included in the BNT, is used to determine the CNT’s inclusion priority. Second, an objective function (OF) is used to evaluate the maximum acceptable number of CNTs based on the priorities derived from the sensitivity analysis. This OF aims to minimize the weighted sum of the average operation time and the number of setting changes for the PDs. Case studies on the test systems were conducted, and the effectiveness of the proposed method was verified by comparing it with existing adaptive protection methods.