Control equipment for MV capacitor banks

Switching capacitor banks

Switching-on a bank of capacitors which is connected in parallel to the network causes transient phenomena resulting from bank charging. As far as the current is concerned, the oscillating load provokes an overcurrent with an amplitude which is a function of the network and bank characteristics.

At the point of consideration, switchingon is equivalent in practical terms to the setting up of a short circuit with short duration (high frequency in relation to the network frequency). From the voltage side, the load is followed by the propagation of a shock wave. These transient phenomena depend on network characteristics and on the timing of contact closing or prestrike.

There are two possible cases: a single bank and a bank divided into several capacitors to be switched independently to the supply system.

AUTHOR: Schneider Electric expert | Denis KOCH