KPM VILA

Vacuum Interrupter are the most critical & most stressed part of a vacuum circuit breaker . The operation of opening and closing of current carrying contacts and associated arc interruption take place in a vacuum interrupter only . The vacuum pressure inside a vacuum interrupter is normally maintained at 10-5 bar. Though service life of vacuum interrupters are much longer than other types of circuit breakers, still failure of Vacuum Interrupters are always a matter of concern for electrical maintenance staff .
The most common method for VI testing is by applying high voltage (DC) across the contacts of the
electrodes and the leakage current is measured , but sometimes this method results in false identification of the faulty Vacuum Interrupter as a healthy one. It has been observed that during applying high DC voltages the polarization of charges happens inside the VI bottles due to this few electrons stick to the electrodes . This results in less leakage current hence giving wrong indication about the pressure condition inside . The
same VI when again put in service might fail again . Hence now the test equipment based on new methodology of Penning Discharge Principle are considered more reliable>