Reactive power management and voltage control in the Spanish electric system

The need for better reactive power management has become apparent for the Spanish high voltage power system where bad voltage profiles and, in some cases, low voltages, have appeared. Based on offline optimal power flow studies, a set of optimal references values for the high voltage generator buses and optimal tap positions have been determined as well as optimal procedures for the connection/disconnection of reactances. After testing in practice the results of the offline studies, a rule based expert system has been developed. Finally, the complete hierarchical voltage control system planned for the Spanish Power System in three levels is outlined