The unbundling of the generation and transmission functions in England and Wales into separate shareholder-owned companies has inevitably resulted in far less predictability in terms of generator siting and closure.(1) National Grid, as the sole transmission company in England and Wales, is required to plan and respond quickly to changing system patterns to maintain both security and power quality standards. This has been achieved by an extensive programme of investment in reactive compensation. To supplement the existing fixed static var compensators installed in the last 10-15 years, National Grid has, to date, installed a further 12 relocatable SVCs at sites in England and Wales as part of a planned programme of work to meet these changing system needs.