1. SF6 relay should have the following functions
1) Monitor the SF6 gas pressure inside the circuit breaker;
2) Distinguish whether the cause of the decrease in gas pressure is the decrease in ambient temperature or gas leakage;
3) When the increased ambient temperature leads to the drop of the pressure, the SF6 relay indicator is basically unchanged;
4) When the pressure drops due to gas leakage, an alarm signal should be issued in time to remind the operator to perform inflation;
5) When the gas leakage is serious, the tripping of the circuit breaker is blocked to avoid tripping under the condition of insufficient pressure and avoid causing the circuit breaker to explode.
2. The basic technical parameter requirements of SF6 relay
Measuring range: -0.1 - 0.5 MPa; -0.1 - 0.9 MPa;
Accuracy grade: when the ambient temperature is +20℃, the accuracy is +1% of the full scale;
Ambient temperature: -20℃ + 60℃, the accuracy is ±2.5% of full scale;
Electric contact type: magnetic assist type;
Ambient temperature: -20℃ - 65℃;
Compensation temperature: -20℃ - 60℃;
Protection level: IP54 - IP65.
3. Verify the safety technical measures of SF6 relay
1) Apply for a work ticket and verify it when the circuit breaker is out of service;
2) Understand the layout of the circuit breaker's gas pipeline, and be clear about the valves that need to be opened and closed during calibration;
3) The SF6 relay with self-reversing valve can be directly removed for verification, as its self-reversing valve automatically closes without air leakage;
4) The connectors of the calibration instrument and the density relay should be matched correspondingly to detect whether there are any leaks to ensure the accuracy of the calibration;
5) The SF6 relay should be tested for alarm and blocking contact;.
6) Workers should wear protective rubber gloves when necessary. In the enclosed SF6 electrical equipment room, gas masks should be worn.
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