Correct Installation and Maintenance of Power Distribution Cabinets
I. Installation of Power Distribution Cabinets
#### (1) Preparations Before Installation
- The installation floor should be flat and solid to bear the weight of the power distribution cabinets. If the floor is uneven, it may cause the power distribution cabinets to tilt after installation, affecting their normal operation and operational safety.
2. **Equipment Inspection**
- Before installation, a comprehensive inspection of the power distribution cabinets should be carried out. Check whether the cabinet body is deformed or damaged, especially whether the opening and closing of the cabinet door is smooth and whether the door lock works properly.
- Check the internal electrical components, including busbars, load switches, current transformers, voltage transformers, instruments, etc. Ensure that the components have no damaged, loose or missing parts, and the models and specifications of each component should meet the design requirements.
- Check whether the terminal blocks of the power distribution cabinets are intact and whether the insulation is good. At the same time, verify whether the technical documents attached to the power distribution cabinets, such as product manuals, wiring diagrams, and certificates of conformity, are complete.
#### (2) Installation Process
1. **Cabinet Installation**
- Determine the installation position of the power distribution cabinets according to the design drawings. Use a crane or forklift to transport the power distribution cabinets to the designated position. During the transportation process, pay attention to avoiding collisions with the cabinet body to prevent deformation of the cabinet body.
- Place the power distribution cabinets on the foundation channel steel and adjust the shims to make the cabinet body reach a horizontal state. The horizontal error generally should not exceed 1.5 millimeters per meter. The gaps between the cabinet bodies should be uniform. Generally, the gap between adjacent cabinet bodies should not exceed 2 millimeters, and it is necessary to ensure that the connection between the cabinet bodies is tight and firm, which can be connected by bolts.
2. **Busbar Installation**
- Before installing the busbars, clean the busbars to remove impurities such as oil stains and oxide layers on the surface of the busbars to ensure good electrical conductivity.
- Install the busbars in the busbar chamber according to the design requirements and installation instructions. The connection of the busbars should adopt an appropriate connection method, such as bolt connection. The connecting bolts should be tightened, and the torque should meet the specified requirements to prevent poor contact and heating. The insulation distances between different phase busbars and between the busbars and the cabinet body should meet the standards. Generally, the distance between phases should not be less than 125 millimeters, and the distance between the busbars and the cabinet body should not be less than 20 millimeters.
3. **Installation and Wiring of Electrical Components**
- When installing electrical components, ensure that the components are firmly installed. For example, the load switch should be installed in its dedicated installation position, and the operating mechanism should be flexible and reliable. The current transformer and voltage transformer should be installed according to the correct polarity.
- The wiring work should be carried out strictly in accordance with the wiring diagram. Select wires and cables of appropriate specifications. The cross-sectional area of the wires should meet the requirements of the current-carrying capacity. When wiring, pay attention to the treatment of wire ends. The wire ends should be crimped firmly to avoid virtual connections. At the same time, ensure that the wiring of the wires is neat and beautiful, and a certain distance should be maintained between different wires to prevent short circuits. The identification of the wires should be clear for the convenience of future maintenance and inspection.
#### (3) Inspection After Installation
1. **Appearance Inspection**
- Check whether the appearance of the power distribution cabinets is clean, whether the cabinet doors are closed tightly, whether the paint layer on the surface of the cabinet body is intact, and whether there are scratches or peeling phenomena.
2. **Electrical Inspection**
- Use an insulation resistance meter to check the insulation resistance of the power distribution cabinets, including the insulation resistance between busbars, between busbars and the cabinet body, and between electrical components. The insulation resistance value should meet the specified requirements, generally not less than 1000Ω/V (rated voltage).
- Check whether the wiring of the electrical components is correct. Through operation tests, check whether the operation of components such as load switches is flexible and whether the actions are accurate. At the same time, check whether the display of the instruments is normal and can accurately reflect parameters such as voltage and current.
### II. Maintenance of Power Distribution Cabinets
#### (1) Daily Maintenance
1. **Appearance Cleaning**
- Clean the appearance of the power distribution cabinets regularly (generally at least once a week). Use a clean dry cloth to wipe the dust and stains on the surface of the cabinet body. In an environment with a lot of dust, a soft brush can be used to sweep first and then wiped with a dry cloth.
- Clean the ventilation openings of the cabinet doors to ensure good ventilation and prevent the internal temperature of the cabinet body from being too high due to poor ventilation.
2. **Inspection of Operating Parameters**
- Check the display of the instruments on the power distribution cabinets once a day, and record parameters such as voltage, current, and power factor. Observe whether these parameters are within the normal range. If abnormal parameters are found, analyze the reasons in time and take measures.
- Check the status of the indicator lights in the power distribution cabinets, including power indicator lights, operation indicator lights, and fault indicator lights, to ensure that the indicator lights work normally and can accurately reflect the operating status of the equipment.
#### (2) Regular Maintenance
1. **Internal Cleaning**
- Clean the inside of the power distribution cabinets every 1 - 3 months (depending on the dust situation of the environment). Before cleaning, disconnect the power supply and ensure that energy storage components such as capacitors have been discharged. Use special electrical equipment cleaners and clean cloths to wipe the dust and oil stains on the surfaces of busbars and electrical components.
- During the cleaning process, pay attention to avoiding the cleaner from entering the inside of the electrical components to prevent damage to the components. At the same time, check whether there are abnormal situations such as loose or discolored internal wiring.
2. **Inspection and Maintenance of Electrical Components**
- Conduct a comprehensive inspection of electrical components every six months to one year. Check the wear of the contacts of the load switch. If the wear of the contacts exceeds the specified limit, replace them in time. Check the accuracy of the current transformer and voltage transformer. If there is a deviation, calibration is required.
- Conduct a functional test on the protection device to ensure that it can act accurately under the set protection setting value. At the same time, check whether the fuse is intact. If it is blown, replace it with a fuse of the same specification in time.
3. **Inspection and Maintenance of Busbars**
- Regularly check whether the connecting bolts of the busbars are loose. If they are loose, tighten them in time. Check whether there are signs of overheating and discoloration on the surface of the busbars. If local discoloration of the busbars is found, it may be caused by poor contact and heating, and further inspection of the connection parts and treatment are required.
- Depending on the actual operation situation, an insulation performance test of the busbars can be considered every 3 - 5 years to ensure good insulation performance of the busbars.
#### (3) Fault Maintenance
1. **Fault Diagnosis**
- When a fault occurs in the power distribution cabinets, first observe the fault phenomena, such as whether there is an abnormal smell, smoke, or abnormal sound. At the same time, check the status of the fault indicator lights and preliminarily judge the fault range according to the prompts of the indicator lights.
- Check the display of the instruments to see whether parameters such as voltage and current are abnormal. For example, if the current is too large, it may be a short circuit or overload fault.
2. **Fault Handling**
- For some simple faults, such as a blown fuse, the fuse can be replaced and the power can be restored, and then observe whether the equipment returns to normal operation.
- If an electrical component is damaged, such as a load switch failure, the faulty component needs to be replaced. After replacing the component, debugging and testing should be carried out to ensure the normal operation of the equipment. For complex faults, such as a short circuit of the busbars, professional maintenance personnel are required to carry out maintenance. During the maintenance process, strictly abide by the safety operation procedures to prevent accidents such as electric shock.
