A primer on capacitor bank protection

Capacitor banks are applied in power systems to provide reactive power. The reactive power results in lower current in lines upstream of the bank impr oving system voltage and power factor and reducing line losses. Capacitor b anks can be configured as filters for harmonic reduction. The protection sy stems for capacitor banks include fuses, surge arresters, and protective re lays. This paper will focus on protective relaying philosophies of grounded and ungrounded Y-connected shunt capacitor banks, which are commonly appli ed on industrial and utility power systems.