Distribution automation case study: Rapid fault detection, isolation, and power restoration for a reliable underground distribution system

Electric utilities continue to deploy innovative technologies in power distribution systems to reduce outage time and provide more reliable delivery of electric power. Fault location and fast service restoration are challenging in underground looped distribution feeder systems electrically separated by normally open switches. Traditional fault location detection methods are time-consuming, labor intensive, costly, and detrimental to field equipment. This paper describes the objectives and operating principles of a centralized and automated underground distribution automation system (UDAS) that was developed and applied for rapid fault detection, isolation, and service restoration. The UDAS significantly reduced outage time and maintenance costs by executing tasks that were previously done manually by a field crew, therefore improving the performance of the distribution system.