Review of trends in excitation systems and possible future developments

Turbine-generator excitation system practice began to undergo a widespread and radical change in the early 1960s as the availability of high-power semiconductor devices promised significant improvements in both performance and reliability. Since that time, semiconductor technology has progressed steadily and its exploitation has been largely responsible for excitation system development being able to keep pace with that of the generators themselves. The demand for advanced equipment of ever greater power-handling capability has been satisfied with less difficulty than could otherwise have been the case. As to the future, improvements in the dynamic performance of electrohydraulic speed governing systems may lead to a relaxation of demand on excitation systems.