Vietnam factory introduction: Low voltage distribution cabinet maintenance methods and standards

Low-voltage cabinet and then to each power distribution box, it is actually some switch circuit breakers and other protective devices assembled into one electrical equipment. In order to ensure the normal operation of the high and low voltage PDC equipment, it is necessary to perform routine maintenance of the high and low voltage PDC.

Low voltage distribution cabinet maintenance method:

1. Implement segmented maintenance, and first maintain the security load section. When maintaining the capacitor cabinet, you should first turn off the capacitor main switch, discharge the capacitors one by one to the ground with a wire of more than 10 mm, and then check whether the contactor, capacitor wiring screws, grounding device is good, check whether the capacitor is expanded, and clean the dust in the cabinet with a vacuum cleaner.

2, stop the security load power, if the load is normal for the mains, disconnect the air switch for the security load mains, put the generator selection switch in the "stop" position, disassemble the positive and negative battery lines, and tie the sign plate to prevent the generator from sending electricity.

3, check the busbar joint for deformation, there is no trace of discharge black, tighten the connection bolts, bolts should be replaced if there is rust, ensure that the connection is tight, check the insulator on the busbar is loose and damaged.

4. Shake the main air switch from the distribution cabinet with the handle, check whether the main contact has melting traces, check whether the isolation cover is burned and damaged, tighten the wiring screws, clean the dust in the cabinet, and test the closing of the machine.

5. Take each separate cabinet out of the cabinet, tighten the wiring terminals, check the installation and wiring of the current transformer, ammeter and watt-hour meter, check the flexibility and reliability of the handle operating mechanism, tighten the inlet and outlet cables of the air switch, and clean the dust in the switch cabinet and the outlet cables behind the distribution cabinet.

6. Step by step, disconnect the low-voltage air switch, and then disconnect the vacuum circuit breaker on the high-voltage side of the transformer to close the grounding switch, and hang the "No closing, someone working" sign.

7. After the maintenance of the security load is completed, the generator can be started to supply power to it, and the mains power supply and maintenance of the busbar section can be stopped.

8, according to 3,4,5 all requirements after the maintenance of the power distribution cabinet, remove the safety device, disconnect the high-voltage side grounding switch, close the vacuum circuit breaker, observe the transformer put into operation without error, power to the low-voltage power distribution cabinet step by step, and the security load generator power supply into the city power supply.

Low voltage distribution cabinet maintenance standards:

A. Daily maintenance cycle: at least once A month

1. Check whether the capacitor shell in the capacitor cabinet is good, whether there is leakage, expansion, and whether the indicator is good;

2. Check whether the cable connector is hot and discolored, and the ground cable is corroded.

3. Check the contact of the ground wire of each capacitor shell;

4. Do a good job of cleaning and dust removal of each cabinet.

B. First level maintenance cycle: at least once every six months

1. Check whether the bus and its lead are securely connected.

2. Capacitor cabinet inspection: When the air switch is disconnected without a capacitor, the capacitor controller should be tested. The first closed should be broken, and the second closed should be broken, and it should be normal. Adjust the overvoltage protection, undercurrent protection and cut-off threshold.

3.. Check whether the secondary circuit wiring is firm, whether the fuse is intact and the insulation resistance is measured.

4. Check whether the indicator light of each cabinet is normal, whether the switch position of the controller is normal, the operation should be normal, and whether the manual debugging of the mechanical chain part is reliable.

5. Each indicator should be in good condition, check and set the circuit breaker, leakage circuit breaker, thermal relay, time relay, etc.

C. The secondary protection period is every year

1. Check whether the knife edge elasticity of the circuit breaker is normal and whether the arc extinguishing device is intact.

2. Check whether the drawer switch is flexible when pushed in or pulled out, its mechanical lock is reliable, and whether the contactor contacts are good.

3. After the main switch of the receiving cabinet and the contact cabinet is powered off, the special crank should be used to shake out or shake in flexibly. The secondary terminals of various transformers and other terminals are in good contact and tight without loosening, and the primary and secondary wires are not moldy.

4. Check whether the connection nuts of each cable connector are secured.