In the SF6 gas density monitor circuit breaker, the decisive factor for its electrical strength and arc extinguishing performance is the gas density, and the main component reflecting the change of the gas density meter is the gas density controller. Therefore, the performance of the density controller directly affects the safe operation of the circuit breaker.
1. Testing requirements and cycle. Test the SF6 circuit breaker gas density monitor that is newly put into operation; for the operating equipment, in the field operation, in order to ensure the breaking capacity and insulation performance of the circuit breaker, the initial period is generally once per year.
2. Test content. The main content of the density monitor performance test on site includes: rated inflation pressure indication, decompression alarm pressure value, decompression lockout pressure value, power frequency withstand voltage, and insulation resistance.
When the density controller is activated, there are mainly the following reasons: the first density controller has an error in its action value, causing a false signal; the second is due to the leakage of the circuit breaker causing the density controller to send a signal; the third is the failure of the secondary electrical wiring; the fourth is that the temperature characteristic pressure difference is too large, that is, the pressure difference between the circuit breaker and the SF6 gas density monitor in the bellows increases due to different temperature changes and falsely sends a signal. When the density controller action occurs in the equipment operation, it is necessary to correctly identify the situation and take corresponding measures in a timely manner.
Firstly, check the pressure gauge value of the circuit breaker, measure the actual temperature and compare with the temperature pressure curve and pressure gauge readings given to determine whether the circuit breaker is leaking; if the circuit breaker is not leaking, check whether the secondary electrical wiring fails; at the same time, check whether there is a different temperature change between the bellows of the density controller and the SF6 in the circuit breaker; if it is confirmed that there is a problem with the density controller itself, it should be replaced.
At present, there are many types of SF6 gas density monitors, but they should all be tested for their working characteristics, and the SF6 gas density relay calibrator should be used for testing. To provide users with safe and reliable products is a responsible attitude towards users. For the operating unit, they should clearly require the circuit breaker manufacturer to install a gas density monitor when ordering to monitor the SF6 gas pressure at any time during operation. This is also one of the inspection items in the high-voltage circuit breaker operating regulations.