What Are The Maintenance Methods For Low-voltage Power Distribution Cabinets

The maintenance of the low-voltage power distribution cabinet is mainly to ensure the normal and safe operation of the low-voltage power distribution cabinet. The low-voltage power distribution cabinet should be inspected and maintained annually. To complete the maintenance with the least power outage time, generally determine the owner's power outage time in advance.

The maintenance content and steps of the low-voltage power distribution cabinet:

1. The maintenance should start from the low-voltage side of the transformer. After the power distribution cabinet is powered off, clean the dust in the cabinet, check whether the bus bar and down conductor connection is good, whether the joint point is heated or discolored, check whether the cable head and wiring pile head are firm and reliable, and check whether the grounding wire is corroded, and the wiring pile head Is it tight? All secondary circuit wiring connections are reliable, and the insulation meets the requirements.

2. When checking the drawer type switch, the drawer type switch cabinet should be flexible when being pushed in or pulled out, and the mechanical locking should be reliable. Check whether the automatic air switch operating mechanism on the drawer cabinet is in place and whether the wiring screws are fastened. Remove the dirt on the contact surface and surroundings of the contactor and check whether the contact of the contactor is in good condition. If the contact is not in good contact, you can slightly repair the contact surface if necessary. If the contact is severely ablated (the contact point is worn to the original 1/3 of the thickness) the contact should be replaced. The power indicating instrument and indicator light are in good condition.

3. When inspecting and repairing the capacitor cabinet, the main switch of the capacitor cabinet should be disconnected first, and after the capacitors are discharged to the ground one by one with a wire of more than 10mm2, the appearance of the shell is good, and there is no oil leakage. If the capacitor shell expands, it should be Deal with it in time, replace the discharge device, the connection screw of the control circuit and the grounding device. After closing, carry out the debugging of the indicating part and the automatic compensation part.

4. Maintenance of the circuit breaker in the power receiving cabinet and the contact cabinet: After disconnecting all loads, use the handle to shake out the circuit breaker. Re-tighten the wiring screws and check whether the elasticity of the blade meets the requirements. Whether the arc extinguishing grid is broken or damaged, manually debug whether the mechanical interlocking opening and closing is accurate, check whether the contact is in good contact, repair the contact surface if necessary, and check whether the internal springs, gaskets, and screws are loose, deformed or fall off .

Maintenance of transformer cabinet:

1. The following steps should be followed before operation: disconnect the load on the low-voltage side one by one, disconnect the circuit breaker on the high-voltage side, close the grounding switch, lock the high-voltage switchgear, and hang on the switchgear handle "No closing "Someone is working" sign, then short the busbar with a wire of 10mm2 or more and hang the ground wire, and tighten the busbar screws.

2. Overhaul operation steps: clean the busbar contacts again, and apply power compound grease, tighten them with new spring washer screws, check the insulators and spacing connections between the busbars for abnormalities, check the current, voltage, The reliability of the connection of the secondary winding terminals of the transformer.

3. Check and test before power transmission: remove all ground wires and short wires, check whether tools are left at the work site, and after confirming that they are correct, close the isolating switch, disconnect the high-voltage side grounding switch, close the high-voltage side circuit breaker of the operating transformer, and take the Lower the sign, send power to the transformer, then close the circuit breaker of the low-voltage side power receiving cabinet, send power to the busbar, and finally close the relevant contact cabinet and the automatic air switches of each branch.

Precautions:

1. Special personnel must be supervised during the maintenance process.

2. The electricity must be checked before work.

3. The maintenance personnel should be familiar with and operate the electrical and mechanical interlocking conditions of the entire distribution cabinet.

4. It is necessary to understand in detail which lines are two-wire power supply during maintenance.

5. When repairing the busbar, the residual charge in the circuit should be fully discharged.