Capacitor bank switching recovery voltages in an electrical power system using different line models

Capacitor banks are used to compensate the reactive power demand of large commercial and industrial loads in order to withstand busbar voltages within specified limits and to minimise electric power system line losses. This requires switching operations of the circuit breakers that produce transients, which may cause system disturbances and a shortage of the capacitors life. In this paper the transient recovery voltages are studied and analysed in an electrical power system using the commercial software package EMTDC/PSCAD. In the simulation it were considered the Pi and the frequency dependent models for the transmission lines. It was also analysed the influence of the transmission lines length. The capacitor bank was connected in star with the neutral solidly grounded and assuming a small capacitance value. Finally, some conclusions were extracted from the obtained results, as well as from previous published papers by the authors that can be used by the circuit breakers designer in order to ensure a reliable operation and an electromagnetic compatibility.