Utility capacitor switching and adjustable speed drives

The circumstances of drives tripped by utility capacitor switching are analyzed using the results of a case study. It is shown that low-loss utility capacitors increase the surge magnitude by decreasing system damping. Surge magnification is possible at lower voltage buses from the capacitor buses. The three conditions for magnification are described. It is shown that drive sensitivity to the surge depends on whether the drive filter inductor is saturated by the surge