As a professional engaged in power system operations, I recognize that medium-voltage (MV) switchgear plays a pivotal role in power distribution, metering, and protection. Ensuring its operational safety and reliability is critical—any malfunction can severely disrupt the entire power system. To enhance reliability, we must prioritize design-level optimizations, enabling MV switchgear to fulfill its functions and safeguard grid stability.1. Definition of Medium-Voltage SwitchgearIn my prac

I. Overvoltage PreventionVacuum circuit breakers excel in interrupting performance, but high overvoltage may occur across inductors during the switching of inductive loads due to abrupt changes in loop current, which requires special attention. When switching small-capacity motors, starting currents are large, so measures like step-down starting should be adopted to limit the current.Transformers with different structures show distinct characteristics: oil-immersed transformers have high impulse

In the first half of 2007, as project participants from the Electromechanical Equipment Company of Huaibei Mining Group, we carried out a technical transformation of the 10kV substation in the East Factory Area. Our primary task was to replace the original 10kV disconnector - oil - immersed circuit breaker units with ZN20 indoor high - voltage vacuum circuit breakers.Previously, the SN10 - 10 oil - immersed circuit breakers had been in operation for an extended period, leading to severe oil leak

Inability to Push In or Withdraw the Draw-out CarriageThe main manifestation is difficulty in inserting the carriage, which may cause equipment damage and threaten production when severe. The causes and countermeasures are shown in Table 1.The circuit - breaker fails to close. It manifests as the closing core actuating but the circuit - breaker not closing successfully; or the closing core not actuating, which shows that the control circuit of the circuit - breaker is open - circuited or the mec

In power system operation and maintenance, we have found that 35kV and 10kV indoor vacuum circuit breakers, as core primary equipment of high-voltage switchgear, are widely used in main grid and user substations due to their high reliability and low maintenance workload. From daily inspections and live detection to routine maintenance, vacuum circuit breakers always remain our key focus, as their operational quality is directly related to the stability and reliability of the power system. This p

Vacuum circuit breakers are widely used in distribution networks. As core components of power supply equipment, their performance hinges on both vacuum interrupters’ capabilities and circuit breakers’ mechanical characteristics (contact opening distance, stroke, pressure, average closing/opening speed, closing bounce time, opening - closing asynchronism, operation times, and cumulative allowable wear of contacts). Both are critical for reliable operation. The vacuum interrupter is th