voltage transient protection for MV Motors
Medium voltage motors are protected with zinc oxide surge arrestors, surge protection capacitors and RC filters. The surge arrestors seem to be the most often used. When capacitors are used, they are used in parallel with surge arrestors. The use of RC filters is has been recommended by studies, but they may need to be custom designed for each installation.

For induction motors, purchasing motors with higher surge voltage withstand capability may be an option. Induction motor installations may include power factor compensation capacitors, but those capacitors may not have the proper characteristics for surge protection.

The mounting location and lead length to surge protection devices must be considered as part of the surge protection design.

Here is an example of MV surge arrestor construction:



Here is a complete 3-phase Controllix assembly with arrestors on top and a 3-phase capacitor on the bottom.