Troubleshooting method for decreasing vacuum degre

2022-08-13
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Fault phenomenon: the vacuum circuit breaker interrupts the current in the vacuum bubble and extinguishes the arc, while the vacuum circuit breaker itself has no device to qualitatively and quantitatively monitor the vacuum degree characteristics, so the vacuum degree reduction fault is a hidden fault, and its risk is far greater than the dominant fault

the main reasons for the decrease of vacuum degree are as follows:

1) there are problems in the material or manufacturing process of the vacuum bubble, and there are small leakage points in the vacuum bubble itself

2) there are problems in the material or manufacturing process of the corrugated tube in the vacuum bubble, and leakage points appear after many operations

3) the split vacuum circuit breaker, such as the vacuum circuit breaker with electromagnetic operating mechanism, will directly affect the synchronization, bounce, overtravel and other characteristics of the switch due to the large distance of the operating link during operation, which will accelerate the reduction of vacuum degree

fault hazard: the reduction of vacuum degree will seriously affect the ability of vacuum circuit breaker to break overcurrent, and lead to a sharp decline in the service life of the circuit breaker

the treatment methods are as follows:

1) when the circuit breaker is regularly powered off for maintenance, the vacuum tester must be used to qualitatively test the vacuum degree of the vacuum bubble to ensure that the vacuum bubble has a certain vacuum degree

2) when the vacuum degree decreases, the vacuum bubble must be replaced, and the travel, synchronization, bounce and other characteristic tests must be done

preventive measures:

1) when selecting vacuum circuit breaker, the feedback value of displacement sensor must be selected as tortuous modulus of elasticity - another term of tortuous modulus of the China Council for the promotion of international trade and the United Nations Industrial Development Organization, using mature products produced by reputable manufacturers

2) select the vacuum circuit breaker integrating the body and the operating mechanism

3) during patrol inspection, operators should pay attention to whether there is discharge outside the vacuum bubble of the circuit breaker. The fatigue limit of engineering metal materials is proportional to the tensile strength, with a ratio of about 0.5. If there is discharge, the vacuum degree test result of the vacuum bubble is basically unqualified, and it should be replaced in time

4) when the maintenance personnel carry out power-off maintenance, they must carry out characteristic tests such as synchronization, bounce, stroke and overtravel to ensure that the circuit breaker is in good working condition

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