Maintenance of vacuum circuit breakers

PUBLISHER:Shanghai Moye Electric Co.,Ltd　RELEASE TIME:2017/7/13

Vacuum circuit breakers are currently widely used in industrial production and distribution, the most common products such as VS1-12 vacuum circuit breakers, but because of its work rated voltage high, current, flying fox ability, resulting in a lot of problems and hidden dangers, A single improper handling, it may lead to a lot of accidents. So this requires us to vacuum circuit breaker selection, installation, operation, maintenance and repair process to strengthen the management of the operation of the vacuum circuit breaker status monitoring and diagnosis of common faults can be timely and accurate treatment.
1, commissioning and transfer test rigorous good equipment debugging and transfer test off to prevent the equipment in the transport changes and institutional adjustment after the emergence of non-matching phenomenon, especially the operating mechanism and vacuum circuit breaker connected after the problem. The main parameters are: closing bounce, opening the same period, distance, compression stroke, closing speed and time, DC resistance, sub-closing action voltage, fracture insulation level, transmission acceptance test, these parameters are Should meet the requirements. In our usual routine maintenance work, mainly found the following problems: the circuit breaker cabinet static contact with the retractable baffle and handcart circuit breaker frame jam caused into the car difficult, the circuit breaker bounce and trip failed, The circuit breaker insulator porcelain bottle is too close to the distance from the rod is broken, closing contactor action characteristics are not good, often after a move can not move or action voltage gradually increased, the vacuum bubble does not meet the requirements of the vacuum, we These issues have been dealt with. On the vacuum circuit breaker commissioning and transfer test work must be strictly done. We should promptly find the insulation breakdown, the body abnormalities, vacuum interrupter leak and bounce, speed, abnormal trip and other unqualified situation, and handled before they can put into operation to ensure safe operation.
2, operation and maintenance, regular inspection
2,1, operation and maintenance operation operation to observe whether the abnormal phenomenon, such as in the circuit breaker is broken, whether there is abnormal discharge sound, power transmission, observe the vacuum interrupter with or without cracks, damage. Found abnormal report immediately, to be confirmed after the repair, and then operate.
2.2, regular inspection Vacuum circuit breaker body defects are: vacuum interrupter leakage, the body insulation breakdown, over voltage protection failure, vacuum interrupter DC resistance failure, the new input circuit breaker refused to reject phenomenon. Regular pressure test, vacuum measurement, DC resistance and sub-closing action voltage value is an important means of finding the above defects.
3, vacuum circuit breaker status monitoring and diagnosis
Vacuum interrupter is a key component of vacuum circuit breakers, it is supported by glass or ceramic and sealed, with static and dynamic contact and shield, vacuum can not be less than 6.6 x 10-2P a. The new vacuum interrupter manufactured by the factory is required to reach below 7.5 x 10-4 Pa. When the vacuum is reduced, the breaking performance is significantly reduced. So the vacuum interrupter can not be hit by any external force or suffered a collision.
3.1, vacuum interrupter inspection Vacuum circuit breaker is the biggest feature of the contact enclosed in the vacuum tube insulation shell, it is under strict quality management using modern equipment made, to ensure long life. In the following circumstances need to be checked, if necessary
Need to replace the vacuum bubble:
(I) Vacuum interrupter has reached the number of on-off times guaranteed by the manufacturer (mechanical life I million);
(2) Vacuum interrupter has reached the specified inspection cycle (minutes, closing times to I million times, short-circuit current 100 times, the arc chamber pressure test, to 20,000 times to replace the vacuum interrupter) ;
(3) appearance when abnormal. Check the basis of: vacuum circuit breaker life by the contact and vacuum 2 indicators to determine:
(1) Determination of contact wear. Use the markings on the contact link of the vacuum circuit breaker to check the mark or use the vernier caliper to measure the contact overtravel. If the dynamic and static contact cumulative wear thickness exceeds the specified range, then the vacuum bubble has been the end of life, should replace the vacuum bubble.
(2) The DC resistance of the vacuum bubble is within the specified range. General vacuum bubble DC resistance is not greater than 2 5μΩ, vacuum circuit breaker conductive loop resistance is not greater than 45μΩ
(3) Vacuum measurement.
① frequency withstand voltage method. So that the circuit breaker in the open state, in the vacuum interrupter contact between the voltage to determine, can withstand 42kV, Imin frequency withstand voltage test, the vacuum bubble should not have a continuous discharge, that is normal.
② vacuum tester test. At present the more accurate method is the magnetron method, suitable for the factory for the vacuum interrupter detection. Vacuum is not greater than 5 * 10-4Pa,
Spark method. Only applies to the glass tube vacuum interrupter, when used, let the spark leak detector in the arc chamber surface movement, in its high frequency electric field under the internal light of different situations. If the tube has a light blue glow, the vacuum in the 1.33 * 10-5 or more; if the red light, indicating that the tube has been invalid; if the tube has been in the atmosphere, it will not light.