ZW7 intelligent column mounted 35KV electric operated high-voltage vacuum circuit breaker

Main features of ZW7-40.5
1. Ceramic column structure, waterproof transmission box, new vacuum arc extinguishing chamber;
2. 2-3 current transformers, with four coils per phase, can be adjusted according to user needs;
3. Can be equipped with CD10 electromagnetic mechanism or CT19 spring mechanism;
4. Good breaking performance, high reliability, long lifespan, and low maintenance workload;
5. Oil free, gasification free, economical and environmentally friendly;
6. After external insulation correction, the current operating altitude is 2700mm.

Regular inspection of ZW7 vacuum circuit breaker:

The common defects of the vacuum circuit breaker body mainly include: chronic leakage of vacuum bubbles, insulation breakdown of the insulation parts of the body, etc. In the absence of comprehensive online monitoring methods, regular insulation inspections, voltage withstand tests, and preventive tests are the main means of detecting the above-mentioned defects. The time when vacuum circuit breakers encounter problems is mainly concentrated between 6 months and 2 years after production, during which the operating state of vacuum circuit breakers is relatively unstable and requires strengthened operation testing. The newly put into operation vacuum circuit breaker has added the content of conducting preventive tests once every 3 months, 6 months, and 1 year after operation, and then conducting pre tests according to the normal pre test cycle, in order to strengthen the operation detection of the vacuum circuit breaker during the unstable period. Practice has proven that the effect is very good.

However, it should be noted that the insulator of the switch body, especially the pull rod insulator, is not a "full working condition" product. During operation, it often causes breakdown or flashover discharge due to insufficient creepage distance and cracks. More attention should be paid to the rod insulators that adopt an inner and outer two-layer structure to meet the climbing distance. The organic filling between the inner and outer layers can also cause surface flashover and penetration when there are bubbles or moisture inside.

(3) Strengthen the operation of ZW7 vacuum circuit breaker:

Pay attention to observing for any abnormal phenomena during operation, such as checking whether the live display device of the cable head displays live after the switch is disconnected during the opening operation; When opening the busbar side knife switch, observe whether there are sparks on the knife edge and whether there are flashes of vacuum bubbles (glass bubbles).

ZW7 intelligent column mounted 35KV electric operated high-voltage vacuum circuit breaker

Accident situation introduction II

15: At 14:45, the load of the unit was 528 MW, and the set load was 550 MW. At this time, the F coal mill was started, and the boiler main control experienced a step change from 89% to 96.74%, and then decreased to 17.25%. The opening of the fan blades of A and B decreased accordingly, and the total air volume decreased to about one-third of the original, and the coal feeding rate decreased to about half of the original. The automatic control of air supply and oxygen supply was manually exited, and the coordinated control should be switched to manual control mode.

15: The load increased at 59:12, causing a rapid rise in the water level of the No. 2 reactor. There was a lag in valve adjustment, and at this time, there was a phenomenon of the No. 2 high-pressure water level interlocking opening the emergency drain valve of the No. 2 high-pressure reactor and closing the normal drain valve of the No. 2 high-pressure reactor.

16: At 01:30, the water level of the No. 3 high-pressure heater reached a high three value disconnection, and the feedwater temperature decreased from 279 degrees Celsius to 180 degrees Celsius. The unit load also increased by 56MW, and the main steam pressure and flow rate increased. The water level in the steam drum dropped to -136 mm. At 16:08:27, due to the decrease in main steam engine pressure, it also dropped to 520MW, and the water level in the steam drum increased by 356mm. At 16:09:23, the water level in the steam drum was too high, causing the boiler MFT.