COMPARATIVE EVALUATION AND ENHANCEMENT OF MURRAYLOOP AND VARLEY-LOOP FAULT LOCATION METHODS FOR AIRFIELD UNDERGROUND LIGHTING CABLES AT NNAMDI AZIKIWE INTERNATIONAL AIRPORT, ABUJA

Abstract

This study investigates the accuracy and limitations of the Murray-loop and Varley-loop fault-location methods as applied to airfield underground lighting cables at Nnamdi Azikiwe International Airport (NAIA), Abuja. While both techniques are classical bridge-based methods for locating faults in underground power systems, their performance under the unique operational and environmental conditions of airfield installations has not been extensively evaluated. Controlled field experiments were conducted on the airport’s lighting circuits to determine fault distance accuracy, and the results were statistically analyzed using Analysis of Variance (ANOVA) to test two formulated hypotheses. The findings revealed that the Murray-loop method exhibits higher fault-location accuracy compared to the Varley-loop method. However, both techniques are prone to cumulative resistance errors and signal attenuation over long distances. Consequently, this study proposes a hybrid diagnostic framework that integrates the traditional bridge-based fault location with Surface-Mounted Radar (SMR) technology for improved precision and automation. This hybridization represents a significant step toward smart, real-time fault management systems for airfield electrical infrastructure.