The vacuum degree of the interrupter chamber in 10kV–35kV vacuum circuit breakers is a key indicator for judging their breaking capability. When the vacuum degree deteriorates to the point of not meeting operational requirements, the interrupter chamber must be replaced promptly. In field operation and maintenance, commonly used detection methods include the power-frequency withstand voltage method, the magnetron discharge method, and the non-detachable vacuum degree tester method. These different schemes differ in applicable scenarios, operational complexity, and data interpretability, and their selection must be checked against actual maintenance conditions.
The power-frequency withstand voltage method qualitatively judges the vacuum degree by applying a specified voltage and observing whether breakdown occurs. It is simple to operate, but can only give a rough "pass/fail" conclusion, making it difficult to reflect the gradual trend of the vacuum degree and insensitive to early deterioration. The magnetron discharge method uses an excitation coil to establish a magnetic field, ionizing the residual gas in the interrupter chamber and inferring the vacuum degree from the ion current, enabling quantitative measurement. However, traditional magnetron discharge devices require dismantling the interrupter chamber or configuring an excitation coil on site, which imposes certain requirements on the power outage window and working space.
The DRV-8600 switch vacuum degree tester adopts a non-detachable measurement method, with a measurement range covering 9.999×10⁻⁵Pa to 1×10⁻¹Pa, and is suitable for vacuum degree detection of interrupter chambers in 10kV–35kV vacuum circuit breakers. Compared with schemes requiring dismantling of the interrupter chamber, this instrument can complete testing without moving the switch body, reducing the impact of disassembly and assembly on seals and contacts; compared with the power-frequency withstand voltage method, its output is quantitative vacuum degree data, making it convenient for O&M personnel to longitudinally compare historical measured values and judge whether the interrupter chamber needs replacement.
From the perspective of field adaptability, non-detachable measurement places relatively high demands on test lead arrangement and magnetic field excitation consistency. During handover acceptance and routine maintenance, O&M personnel should fix the interrupter chamber model and test position and maintain the same wiring method, so that data from successive tests are comparable. For factory inspection, the quantitative measurement scheme can be used in conjunction with the withstand voltage test, with the former used for trend judgment and the latter for insulation margin verification. When measured values approach the critical range, a comprehensive assessment should be made in combination with factors such as the number of breaking operations and operating years of the circuit breaker, rather than drawing conclusions based on a single measurement alone.
