Retrofit in asset life management

The electricity supply industry in the United Kingdom is based on a distribution system which was established predominantly in the 1950s and 1960s. The Regional Electricity Companies (RECs) therefore have a large population of equipment such as high-voltage switchgear which is nearing the age where its replacement will be required. Manufacturers have begun to recognise the challenges and opportunities that this brings, and some are now offering products and services that provide realistic options for asset life management. This paper focuses on the need for replacement of high-voltage switchgear (11 kV) and discusses the option of retrofitting new vacuum circuit breakers into existing switchboards. The paper is based on the experiences of one UK Regional Electricity Company-London Electricity (LE)-and a manufacturer of high voltage switchgear-Reyrolle Projects Ltd. Retrofit has been successfully applied at a number of the RECs substations. The constraints in carrying out replacement at live operational substations was an important consideration in selecting the option of retrofit and the learning points of this experience are discussed. Provision of control facilities new circuit was an added benefit as was the replacement of electro-mechanical relays with digital (microprocessor) relays, providing enhanced information and communications.