ABSTRACT
It is common practice to install shunt capacitors to improve the power factor and voltage profile at all voltage levels in the power system. It is also a well-accepted practice to improve the power factor of the industrial systems using local capacitor banks. If the industrial load is fed from converter equipment, then notch filters are used to control the power factor and harmonics simultaneously. These shunt capacitor banks are switched in and out as needed. The switching operations include energizing, de-energizing, fault clearing, backup fault clearing, and reclosing. Sometimes a restrike occurs due to excessive voltage across the circuit breaker blades. Further, in the capacitor banks there may be bus fault conditions responsible for significant outrush current. There is also energization of a capacitor bank when another capacitor bank is charged, i.e., the back-to-back switching. Sometimes the EHV or HV systems are connected to the low voltage system using stepdown transformers. It is known that the voltage magnification will occur in the low voltage capacitor banks at certain conditions when the switched HV capacitors are significantly larger in size. It can be seen that there are several technical issues involved in switching of the capacitor banks.
Such capacitor switching transients are analyzed in References [1-3]. The switching studies are performed using the Electro Magnetic Transients Program [4].
