New achievements in pressure relief tests for polymeric-housed varistors used on series compensated capacitor banks

Recent pressure relief tests on polymeric-housed arresters for use on series capacitor bank varistors have been carried out with successful results. The increased Mvar rating within a single segment platform does significantly increase the prospective capacitor fault current discharge and energy to values beyond what has been previously tested for Hydro-Quebec series capacitor compensation installations. Tests performed showed that the proposed arresters were fully adequate to withstand these increased thermal and mechanical stresses. Tests have also shown that the capacitor discharge current and frequency can induce significant currents and voltages in laboratory control, protection and measuring wiring systems. Care regarding the test set-up layout, measurement and control techniques shall be taken to avoid or to minimize the induced currents and voltages. This paper gives a summary of the results obtained and describes the mitigation actions taken for reducing such induced currents and voltages to an acceptable level.