SWITCHGEAR: retrofit, refurb or replace?-the asset managers dilemma. REC point of view

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 now have a large population of equipment such as high-voltage switchgear which is nearing the age where its replacement will be required. However, end of life may not affect all components of switchgear at the same time and extension beyond normal life expectancy may be be realistic, e.g. fixed compound filled compartments. In recent times, this approach has been adopted and has proved a satisfactory option for retrofitting new 11 kV vacuum circuit breakers into existing switchboards. In other cases it may be deemed appropriate to refurbish/uprate switchgear. In London Electricity (LE) there is 20 years experience of projects associated with 11 kV switchgear modernisation to enhance performance. This paper discusses the drivers and requirements determining this approach and what factors were important to its success