1. Purpose To ensure the normal and safe operation of low-voltage power distribution cabinets and control cabinets of various equipment.

2. The scope is suitable for power distribution cabinets in low-voltage power distribution rooms. The control cabinets of each equipment shall be implemented in accordance with the relevant clauses according to specific conditions.　　　　　　　

3. Responsibility The maintenance team of the Mechanical and Electrical Installation and Maintenance Engineering Department conducts a comprehensive inspection and maintenance of it every six months, and completes the maintenance work with the shortest power outage time.　　　　　　　

4. Content　　　　　　　

1. Preparation:　　　　　　

A. Inform the residents of the start and end time of the power outage one day before the power outage maintenance of the distribution cabinet.
B. Make all preparations before the power outage, especially the preparation of tools should be complete; and complete the maintenance work with the shortest power outage time

2. Maintenance procedures:

A. Implement segmented maintenance, first maintaining the security load segment.
B. Stop the security load, and the rest of the load will be supplied to the city as usual. Turn off the air switch for the mains power supply for the security load, turn off the generator air switch, put the generator selector switch in the stop position, disassemble the positive and negative lines of the battery, and hang the nameplate to prevent the generator from sending electricity.
C. Check whether there is deformation at the bus bar joint, and whether there are black marks of discharge. Tighten the connecting bolt. If the bolt is rusted, it should be replaced to ensure that the joint is tightly connected. Check the insulation on the mother for looseness and damage.
D. Use the handle to shake the total air out of the power distribution cabinet, check whether the main contact has traces of melting, check whether the arc extinguisher cover is burnt or damaged, tighten the wiring screws, clean the dust in the cabinet, and test the mechanical combination. Brake, opening situation
E. Take out the sub-switch cabinets from the drawer cabinet and fasten the wiring terminals. Check the installation and wiring of current transformers, ammeters, and watt-hour meters, check the flexibility and reliability of the handle operating mechanism, tighten the air inlet and outlet wires, and clean the dust inside the switch cabinet and the outlet wires behind the power distribution cabinet.
F. When maintaining the capacitor cabinet, first turn off the main switch of the capacitor, discharge the capacitor to the ground one by one with a wire of 10MM2 or more, then check whether the contactor, capacitor wiring screw, and grounding device are in good condition, check whether the capacitor is bloated Clean the dust in the cabinet with a vacuum cleaner.
G. After the maintenance of the security load section is completed, the generator can be started to supply power to it, and the mains section can be maintained after the mains supply is stopped.
H. Disconnect the low-pressure side air switch step by step, and then turn off the high-voltage side vacuum circuit breaker for the transformer, close the grounding switch, and hang the "Forbidden to close, someone is working" sign.
I. After maintaining the power distribution cabinet according to all requirements of items C, D, E, and F, remove the safety device, disconnect the high-voltage side grounding switch, close the vacuum circuit breaker, observe that the transformer is put into operation, and then move to the low-voltage distribution cabinet. Power transmission, and transfer the security load from generator power supply to mains power supply.

V. Safety precautions

1. Check the electricity after the power failure.
2. When maintaining the power distribution cabinet in stages, isolation devices should be installed at the junction of the live and unpowered power distribution cabinets.
3. When operating high-voltage side vacuum circuit breakers, wear insulated boots, insulated gloves, and have a special person to monitor.
4. When maintaining the capacitor cabinet, it is strictly forbidden to touch it before the capacitor discharges to the ground.
5. Before the power supply is completed, check whether any tools are left in the power distribution cabinet.

6. Related documents and records

1. Inspection work ticket;
2. Annual maintenance records of distribution cabinets and control cabinets;
3. Equipment maintenance records.