Generator excitation system performance requirements arising from grid system considerations

The author examines the generator excitation system performance requirements arising from transmission system considerations with particular reference to the existing National Grid Company plc grid system and its future developments. The developing trends of higher per unit reactance generating equipment designs and increased utilisation of transmission systems over the past few decades has placed increased emphasis on excitation and other control systems to provide the compensating effects to offset reductions in system stability margins arising from these design trends. At the same time developments in computational system analysis and control equipment design techniques have improved considerably to enable design of excitation and other control equipment with appropriate characteristics