In this paper

the origin and necessary conditions for case rupture of the high voltage shunt capacitors in operation are analyzed.It is thought that when only such three conditions as

Internal cross-cutting breakdown occurs through the capatitor

Has sufficient short circuit capacity at the joint point of the capacitor bank to system or sufficient capacity of shunt capacitor bank

A low resistance discharge channel is in essence between the terminal of failure capacitor and the system or other parallel normal capacitors

the capacitor case rupture may occur.Also the countermeasures and suggestions to prevent the case rupture accident for the high voltage shunt capacitors are proposed.