Study on inner vacuum pressure measurement system of vacuum circuit breakers

This paper proposes an improved method to measure vacuum online which includes signal processing circuit and control algorithm. Firstly, the equivalent capacitance, between vacuum circuit breaker contacts and the shielding cover, is analyzed by Ansoft software. The differences of equivalent capacitance between the condition of separation of contacts and the condition of contacts closure, are researched at the same time. Secondly, The signal processing circuit is built in TINA software, and the feasibility of the signal processing circuit is proved by experiments. Thirdly, using the measurement method to build online vacuum monitoring platform, the results are compared by controlling each part of the circuit and algorithm. It verifies the necessity of each part in the design. Finally, The stability test shows that in the range of the degree of vacuum 9 × 10
^-3
Pa to 2 Pa, compared with the direct measurement result, the signal processing method can increase the measuring accuracy, so as to meet the requirements of measuring vacuum circuit breakers' inner vacuum pressure on-line.