A vacuum interrupters internal pressure on-line condition monitoring system

The reliability and intelligence of vacuum circuit breakers related to the digitization of the substations directly, however, the internal pressure in vacuum interrupters (VIs) is an important indicator parameter of the breaking capability and life. To realize the On-line condition monitor of VIs´ internal pressure, weighting the domestic and international on-line monitoring method, we select the coupling capacitance sensor with Advantages of simple composition, long service life and low cost, Real-time monitoring the AC component variables(Δ U_AC) and DC component variables(Δ U_DC) potential on shield of VIs. Two processors was configured on the monitor system respectively EP2C8Q (FPGA) and TMS320LF2812 (DSP), trying to play the superiority of the two processors and achieve the optimal efficiency. Besides, the conversion algorithm of changing potential on shield of VIs to internal pressure values was studied and the Ethernet communication module based on IEC61850 was designed for uploading data in IED of process level to BAY/UNIT level. Besides, the system was designed with high EMC to ensure the anti-jamming capability. Experimental data and on-site operating results proved that the monitor devices get the advantages of high sensitivity, reliability and strong EMC, and it was applicable in new generation of smart grid.