Maintenance Planning and Execution of Protection Systems in Substations in South Africa: A Recent Case Study

The need to maintain and replace ageing equipment in South African national energy utility (ESKOM) and local municipalities has increased over the years. The country is currently experiencing power cuts from time to time inconveniencing factories and customers at large, as a result. This paper focuses only on the maintenance planning and execution of protection system of the utility distribution substations. Majority of these substations have equipment past their rated operational age. Due to lack of maintenance, their poor condition plays big role in overall power cuts. There is a new program by municipality for replacement of electromechanical relays with recent digital technology in all distribution substations. Technology in protection relays has evolved from mechanical relays to digital relays and then lately to microprocessor-based relays. This paper reviews new technology available to the utilities, its benefits and impacts in the overall system and discusses how these can replace the older relays in distribution substations in South Africa through maintenance planning and execution.