Development of on-line monitoring system for vacuum degree of vacuum switch

The vacuum degree is the main factor for vacuum breaker credible running. When vacuum degree becomes bad, the electric potential of shield will be drop and electric field intensity outside the shield will be changed correspondingly. So vacuum degree can be examined through detecting the electric potential of the shield and electric field intensity outside the shield. Based on principle recommended above, an on-line monitoring system for vacuum degree of vacuum switch is developed. This system adopts electric field sensor developed independently to measure the electric field intensity outside the shield. Sensor has high sensitivity and good insulation function because of only light connection between its probe and bottom. This monitoring system adopts LabVlEW to fulfil the system management and detecting signal processing. The results of experiment and field test show that this monitoring system can effectively detect the vacuum deterioration of vacuum switch.