(1) Equipment requirements
The appearance inspection of the cabinet (panel) body should be free of damage and deformation, and the paint should be intact and undamaged. Internal inspection of cabinet (panel): Electrical devices and components, insulation porcelain parts are complete and free of defects such as damage and cracks.
Before installation, it is necessary to verify whether the distribution box number matches the installation location, and check the box number and circuit number inside the box according to the design drawings. The grounding of the box door should use soft copper braided wire and dedicated wiring terminals. The wiring inside the box should be neat and meet the design requirements and acceptance specifications (GB50303-2002).
(2) Working conditions
The civil engineering of the installation site for the distribution box should have the basic conditions of internal painting completed and doors and windows installed. Pre embedded pipelines and components should be cleaned properly; The site has transportation conditions and the roads are kept smooth and unobstructed.
(3) Distribution box positioning: Determine the location of the distribution box on site according to the design requirements and the actual equipment installation situation on site, and perform wire positioning according to the external dimensions of the box.
(4) Basic steel installation
1) Prefabricate and process the foundation steel frame according to the drawing requirements, and do a good job of anti-corrosion treatment. Place the prefabricated foundation steel frame on the reserved iron parts according to the position marked on the construction drawing, level and align it, and then weld the foundation steel frame, embedded iron parts, and gaskets firmly with electric welding. The top of the final foundation steel should be 10mm higher than the leveled ground.
2) Grounding of foundation steel: After the installation of foundation steel, the grounding wire should be welded firmly to both ends of the foundation steel, with a welding surface twice the width of the flat steel, and then reliably connected to the cabinet grounding bar. And carry out anti-corrosion treatment.
(5) Installation of distribution cabinet (panel)
1) Installation of cabinets (panels): The distribution cabinets should be arranged according to the construction drawings and placed one by one on the foundation steel in sequence. The adjustment of the verticality of the cabinet surface and side can be solved by adding shims to a separate cabinet (panel), but it cannot exceed three pieces and should be welded firmly. After each cabinet (panel) is in place, the levelness of the cabinet and the deviation of the panel surface should be adjusted to comply with the construction specifications.
2) Wall mounted distribution boxes can be fixed to the wall using expansion bolts, but for hollow brick or block walls, dovetail bolts should be embedded or split bolts should be used for fixation.
3) The installation of the distribution box should be pre embedded with a cover box, and the panel should be level with the wall after installation.
4) After the adjustment of the cabinet (panel) is completed, the cabinet body should be fastened to the foundation steel with bolts.
5) Cabinet (panel) grounding: Each cabinet (panel) is separately connected to the foundation steel, and copper wire can be used to reliably connect the PE row inside the cabinet to the grounding bolt, and spring washers must be added for anti loosening treatment. Each cabinet door should be reliably connected to the PE busbar with copper braided wire.
6) The top of the cabinet (panel) should be connected to the busbar, and attention should be paid to using a busbar matching wrench to tighten it according to requirements. The contact surface should be coated with neutral Vaseline. When connecting busbars between cabinets, attention should be paid to whether the busbars are too close to other devices or shells, and to ensure correct phase.
7) Control circuit inspection: Check whether the circuit has become loose due to transportation or other factors, and tighten it one by one, and whether the electrical components are damaged. In principle, the control circuit of the cabinet (panel) should be calibrated before leaving the factory, and the circuit inside the cabinet should not be adjusted without authorization. If any problems are found, the supplier should be contacted.
8) After calibrating the control line, bend each core wire into a circle and connect it to each terminal board with galvanized screws, eye sockets, and spring washers. Generally, one terminal on each side of the terminal board is pressed with one wire, with a maximum of two wires, and eye circles are added between the two wires. Multiple strands of wire should be tinned and there should be no broken strands.
(6) Cabinet (Panel) Test Adjustment
1) The high-voltage test should be conducted by a testing unit licensed by the local power supply department. The test standards comply with national regulations, local power supply department regulations, and product technical data requirements.
2) Test content: high-voltage cabinet frame, busbar, lightning arrester, high-voltage porcelain bottle, voltage transformer, current transformer, various switches, etc.
3) Adjustment content: overcurrent relay adjustment, time relay, signal relay adjustment, and mechanical interlock adjustment.
4) Secondary control small wire adjustment and simulation test, tighten all terminal screws again.
5) Insulation test: Use a 500V insulation resistance tester to test the resistance of each circuit at the terminal board, and the resistance must be greater than 0.5M Ω.
6) If there are transistors, integrated circuits, or electronic components in the secondary small wire circuit, a multimeter should be used to test whether the circuit is connected.
7) Connect temporary control power and operation power; Remove the upper phase wire of the control and operation power circuit fuse inside the cabinet (panel) and connect it to a temporary power supply.
8) Simulation test: According to the requirements of the drawing, simulate the control, interlocking, operation, relay protection, and signal action of the test, which are correct, sensitive, and reliable.
9) Remove the temporary power supply and reset the removed power cord.
(7) Conditions for power transmission operation
1) All installation tasks should be completed and inspected by the quality inspection department to be qualified. All test items are qualified and there is a test report. 2) The testing equipment, insulation boots, insulation gloves, temporary grounding braided copper wire, insulation rubber pads, powder fire extinguishers, etc. should be fully prepared.
3) Check for any remaining debris on the busbar and equipment.
4) Organize the trial operation well, clarify the trial operation commander, operator, and guardian.
5) Clean the dust from equipment, transformer and distribution rooms, and control rooms. Use a vacuum cleaner to clean electrical appliances and instrument components.
6) The relay protection action is sensitive and reliable, and the control, interlocking, signal and other actions are accurate and error free.
(8) Power transmission
1) After passing the inspection by the power supply department, the power supply will be sent into the building, and after verification and phase calibration, there will be no errors.
2) Close the switch of the incoming cabinet by the installation unit and check if the three-phase voltage on the PT cabinet is normal.
3) Close the transformer cabinet switch and check if the transformer has power.
4) Close the incoming switch of the low-voltage cabinet and check if the three-phase voltage on the voltmeter is normal.
5) Deliver electricity in the order mentioned above.
6) Perform phase verification on the upper and lower sides of the switch (switch not closed) inside the low-voltage communication cabinet. Use a voltmeter or multimeter with a voltage range of 500V, and connect the measuring pins of the meter to the same phase of two circuits. If there is no reading on the voltmeter at this time, it indicates that the two circuits are in the same phase. Using the same method, check the other two phases.
7) Acceptance: After 24 hours of no-load operation without any abnormalities, the acceptance procedures will be completed and handed over to the construction unit for use. Simultaneously submit technical documents such as change negotiation records, product qualification certificates, manuals, test reports, etc.