Recovery voltage study of capacitor bank switching for 150kV electrical system in Indonesia

Abstract

In Indonesia, there are many capacitor bank installed to regulate the nominal voltage. Currently, the Recovery Voltage (RV) data related to the capacitor bank switching is unavailable, whereas this data is very important to analyze Circuit Breaker (CB) performance to understand whether it will success to interrupt the current or not. In addition, if the CB cannot retain the RV, it will degrade the CB contacts and possible to broke the CB. Therefore, this paper presents the study of RV for 150kV electrical system in Indonesia. The Result showed that the RV is affected by the source impedance value. Furthermore, for normal condition, the value of RV on the CB for capacitor bank with neutral grounded or ungrounded remains within the limits permitted by the standard. However, in the short-circuit condition, the Transient Recovery Voltage (TRV) and Rate of Rise of Recovery Voltage (RRRV) values can exceed the standard values. This TRV problem can be solved by grounding the capacitor bank. Meanwhile, RRRV problems can be handled by installed a surge capacitor that mounted and arranged in parallel (phase to neutral) to the CB.