6 essential maintenance of low voltage switchboard control cabinet

1. Purpose to ensure the normal and safe operation of the low-voltage switchgear and the control cabinet of all equipment.

2. The scope is suitable for switchgear of low-voltage distribution room. The control cabinet of each equipment shall be implemented according to the relevant provisions and the specific situation.

3. The maintenance team of the mechanical and electrical installation and maintenance engineering department shall conduct a comprehensive inspection and maintenance every six months, and complete the maintenance work within the shortest blackout time.

4. Content

Preparation:

A. Inform households of the start and end time of power failure one day before power failure maintenance of lv panels.

B. Make all the preparations before the power failure, especially the preparation of tools should be complete; Complete the maintenance work with the shortest blackout time.

Maintenance procedures:

A. Implement segment maintenance, first maintain the security load section.

B. Stop the security load power, the rest of the load provides electricity supply as usual. Disconnect the air switch for the security load mains power, disconnect the air switch for the generator, put the generator selector switch in the stop position, disassemble the positive and negative lines of the battery, and hang a sign to prevent the generator from sending power.

C. Check whether the busbar joint is deformed or blackened by discharge. Tightening the connecting bolt. If the bolt is rusty, it should be replaced to ensure the joint is tightly connected.

Check the insulation on the bus for looseness and damage.

D. Shake the general air out of the industrial switchgear with the handle. Check whether the main contact has burned traces of dissolution, check whether the arc extinguishing cover is burned black and damaged. Tighten the wiring screws, clean the dust in the lv panels, and test the closing and opening of the machine.

E. Take each switch cabinet out of the withdrawable switchgear and tighten each terminal. Check the installation and wiring of current transformers, ammeters, and electric hour meters. Check the flexibility and reliability of the handle operating mechanism, tighten the air switch inlet and outlet lines, clean the dust in the switchgear and the outlet lines behind the distribution cabinet.

F. When maintaining the capacitor cabinet, disconnect the main switch of the capacitor first. Discharge the capacitor one by one to the ground with a wire of more than 10MM2, and then check whether the contactor, capacitor wiring screw and grounding device are good, check whether the capacitor bulges or not, and 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 the security load section, and the commercial power can be cut off to maintain the bus section.

H. Disconnect the low-voltage side air switch step by step, and then disconnect the high-voltage side vacuum circuit breaker for transformer power, close the ground switch, and hang the sign "No closing, someone is working".

I. After the maintenance of the industrial switchgear is completed according to the 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 the correct operation of the transformer, and send power to the low-voltage switchgear step by step, and transfer the security load from the generator to the municipal power supply.

5. Safety precautions

The electricity is fulfilled after the power failure.

Isolation device should be installed at the junction of live and non-live switchgear when maintaining the industrial switchgear in sections.

When operating the high voltage side vacuum circuit breaker, we should wear insulation boots, wear insulation gloves, and have a special person to monitor.

When maintaining the capacitor cabinet, it is strictly prohibited to touch the capacitor before discharging to the ground.

Before power transmission after maintenance, check whether any tools are left in the low voltage switchboard.

6. Relevant documents and records

Annual maintenance records of lv panels and control cabinets;

Equipment maintenance records.