Interlocking between the position of the high-voltage switchgear handcart and the circuit breaker
1. Only when the circuit breaker on the handcart is in the open state can the interlocking inside the handcart chassis that prevents the handcart from moving be unlocked, and the handcart can leave the open position/test position or working position.
2. Only when the handcart is locked in the disconnected/test position or working position can the electrical control circuit on the handcart be connected, and the interlocking inside the handcart chassis that prevents the circuit breaker from closing can be unlocked, and the circuit breaker can be closed.
3. When the handcart is in the middle position, the electrical closing circuit and mechanical transmission system of the circuit breaker are locked, and the circuit breaker cannot be closed.
If any abnormalities are found, the equipment shall not be powered on; If the insulation value is qualified, switch the circuit breaker to the required state according to the requirements of the switching operation ticket.
Precautions for insulation value measurement of electrical equipment in high-voltage switchgear:
1. Confirm the measuring equipment to prevent accidental entry into the live space;
2. The equipment switch must be in a cold standby state before measurement is allowed. Before measurement, confirm that no one is working on the equipment circuit;
3. Fully discharge the equipment before measurement to prevent residual charges from injuring people
4. Measure according to the usage specifications of the megohmmeter (including the selection of the voltage level of the meter, the judgment of the meter's quality, operating specifications, and discharge regulations after measurement);
5. Wear insulated gloves according to regulations, and maintain a safe distance from live equipment during measurement;
Before measurement, it is necessary to confirm the outlet side to prevent confusion between the power supply side and the outlet side. During measurement, the "E end" of the megohmmeter should be connected to the ground wire bar of the distribution cabinet or a well grounded metal cabinet.
When the equipment needs maintenance and the switch cabinet needs to be turned to the maintenance state, the three-phase grounding wire should be hung on the outgoing copper bar. Before hanging the grounding wire, attention should be paid to check and confirm the high-voltage switch cabinet door of the equipment to prevent the charged interval from entering by mistake, and the high-voltage electroscope should be used to verify that there is no voltage.
