Determining Impact of Lightning Strike Location on Failures in Transmission Network Elements Using Fuzzy Decision-Making

This paper presents a new approach for determining the impact of lightning strike currents on transmission network elements failures, based on fuzzy logic (FL) and expert systems. The location of lightning strike is determined by means of lightning location system (LLS) and failures in the transmission network, sorted by type of the equipment, are obtained from supervisory control and data acquisition (SCADA) system. The input data set includes two sets. The first set consists of lightning strike locations and current values between the cloud and the ground. The second set consists of current values from SCADA system before and after the fault, protection tripping information, and the state and position of the switches. The proposed FL-based solution is based on a fuzzy decision-making system (DMS), including both data sets in order to provide a power system operator (PSO) with a precise and accurate decision needed in time of emergency. The described model has been tested for functionality and correct results have been obtained, which confirms the membership function (MF) assessment and proves the efficiency and authenticity of the proposed DMS.

I. Introduction

Lightning strikes can cause extremely complicated failures in transmission network elements, which are one of the most common events in transmission lines and parts of the switchgear failures. When a fault happens, in the short time necessary for system management through failure, it is difficult to determine the cause of the fault, the failure initiator, and the location of the lightning strike, if the failure is caused by lightning. Experienced operators are exposed to a multitude of information at the times of failure. Also, it is difficult to discern what the real cause is and what the outcome of a primary event is [1].