According to DL/T 596—2021 Preventive Test Code for Electric Power Equipment, the vacuum degree of a vacuum circuit breaker arc extinguishing chamber should not be lower than 6.6×10⁻² Pa. In field operation and maintenance, testers based on the magnetron discharge method are a common means of evaluating vacuum degree. The following compares this model with conventional solutions in practical operation from the perspective of application scenarios.
Conventional testers require the arc extinguishing chamber to be removed for separate testing before measurement, which is inconvenient for circuit breakers fixedly installed in switchgear cabinets. This model supports direct testing of the arc extinguishing chamber outside the switchgear cabinet by applying a magnetic field through a dedicated coil, without removing the arc extinguishing chamber or primary wiring. For 35kV and below handcart-type switchgear cabinets, maintenance personnel can complete vacuum degree screening of a single circuit breaker within the maintenance window, reducing power outage time and disassembly/assembly workload. During measurement, the instrument automatically completes ion current acquisition and vacuum degree conversion and displays a real-time curve, facilitating judgment of the arc extinguishing chamber status.
The on-site electromagnetic environment is complex. Under conventional solutions, when the busbar is energized or adjacent equipment is running, the ion current signal is susceptible to power-frequency interference, causing reading fluctuations. This model adopts a shielded ion current sensor and digital filtering algorithm. The ion current measurement range is 9.999×10⁻⁵～9.999×10⁻¹ A, and stable readings can still be maintained under conditions where adjacent live parts exist. Compared with early testers using analog pointer meters, digitally quantified results have better repeatability, facilitating longitudinal comparison of historical test data for the same circuit breaker.
Test results can be stored and exported to a backend system, supporting ledger establishment by substation, bay, and equipment number. Maintenance personnel can update the vacuum degree trend curve after each routine inspection, providing a basis for the arc extinguishing chamber replacement cycle. Compared with conventional solutions that can only record readings on site, this model reduces manual transcription and lowers the risk of data errors and omissions.
Applicable scenarios include: vacuum degree general survey of arc extinguishing chambers of 10kV～35kV vacuum circuit breakers in substations, confirmation of arc extinguishing chamber status after maintenance, and regular spot checks of arc extinguishing chambers during operation.
