The electrical service life of an outdoor high-voltage vacuum circuit breaker refers to the number of full-capacity interruptions specified in the equipment's technical specifications and actually performed in type tests. In practical applications, the contacts of high-voltage vacuum circuit breakers cannot be repaired or replaced, so it is necessary to require outdoor high-voltage vacuum circuit breakers to have a sufficiently long electrical service life.
The new generation of vacuum interrupters adopts axial magnetic field electrodes and copper-chromium contact materials. Axial magnetic field electrodes significantly reduce the arc voltage (arc energy) under the action of short-circuit interrupting current and ensure uniform distribution of the arc on the contact surface; copper-chromium contact materials reduce the contact ablation caused by unit arc energy. The organic combination of these two technologies has achieved a breakthrough improvement in the electrical service life of outdoor high-voltage vacuum circuit breakers. Currently, China's outdoor high-voltage vacuum circuit breakers exhibit high and stable performance in terms of interrupting and closing capabilities.
In the early days, the electrical service life of China's outdoor high-voltage vacuum circuit breakers was only 30 times. Some of them have been in operation for more than 20 years, and no outdoor high-voltage vacuum circuit breakers in the power system have been retired due to insufficient electrical service life for short-circuit interrupting current, nor have any accidents occurred due to the short electrical service life for short-circuit interrupting current. This fully indicates that these high-voltage vacuum circuit breakers can basically meet the power system's requirements for the electrical service life of short-circuit interrupting current. Therefore, the electrical service life of outdoor high-voltage vacuum circuit breakers for short-circuit interrupting current is not the longer the better.
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