What are the installation specifications for high-voltage distribution cabinets?
The installation of electrical cabinets is mainly divided into two categories: low-voltage and high-voltage distribution cabinets, which are used in related fields according to different performances. Among them, the distribution cabinets are suitable for power distribution systems in power plants, metallurgy, petroleum, chemical industry, high-rise buildings and other industries. Because the high-voltage and low-voltage distribution cabinets and switch cabinets mainly control electricity, and the safety requirements of electricity itself are very strict, when the distribution equipment is overloaded or short-circuited, the high-voltage and low-voltage distribution cabinets and so on should be able to withstand the mechanical stress and high temperature caused by large current, that is, they can meet the requirements.
1. Check the preparatory work before installation
Before installation, the supervision engineer and the engineer of Party A should check whether the access road is clear, and if necessary, ask the general contractor to build a simple transportation channel to connect with the installation points, and the construction site layout should meet the requirements of safe and civilized construction. At the same time, we should also check the arrangement of construction machines and tools of the installation unit, and urge the installation unit to check the construction machines and tools to ensure that they are in good condition. Before the high-voltage equipment arrives at the site, the power distribution cabinet, power distribution room, trench and foundation channel steel should have been completely completed.
1), transformer room
Power distribution room: Before the construction of the power distribution room, the detailed drawings required for the construction of the power distribution room shall be submitted to the constructor (within 2 weeks after the contract is signed, it is important to confirm the position, content and completion time of the drawings by the customer), and during the construction of the power distribution room, the technicians of our company or cooperative units shall supervise on the spot to avoid construction mistakes. (It takes about 2 weeks to build the distribution room)
2) Foundation: The placement position of channel steel should correspond to the equipment air duct reserved in the distribution room, and the minimum distance between the equipment and the wall should be clear (the distance is too close to open the cabinet door of the equipment). (The welding of channel steel takes about 2 days, and our technicians must be present for guidance.)
Equipment arrived at the site:
3) If the distribution room and foundation are not built, the equipment should be stored (rain proof or provide necessary rain proof materials).
Step 2 install
2.1 The doors and windows of each transformer room shall be tight and the room shall be clean.
2.2 The switchboard shall be installed firmly. The equipment in the tray is firmly connected with each component.
2.3 The grounding of panels and cabinets shall be firm and good. Openable trays and doors equipped with electrical appliances should be reliably connected with grounded metal frames by flexible wires.
2.4 Terminal boxes shall be installed firmly and well closed, and the installation position shall be easy to check. When installed in columns, they shall be arranged neatly.
2.5 The wiring in the switchboard should be horizontal and vertical, the screws should not be loose, and the thread ends should be in good contact.
2.6 All components in the disc are fixed reliably without looseness, and the contacts are free from oxidation and * * pricking.
2.7 The connectors of the secondary circuit shall be made of copper products. Specific requirements for wiring:
2.7.1 circuit connection (bolt connection, plug-in, welding, etc.) shall be firm and reliable.
2.7.2 The end of cable core and matched conductor shall be marked with its loop number; The number should be correct, the handwriting should be clear and not easy to fade.
2.7.3 wiring neat, clear and beautiful; Conductor insulation is good, no damage.
2.7.4 There should be no joint for the wires in the panel and cabinet.
2.7.5 Generally, there is one wiring on each side of each terminal board, and there shall be no more than two.
2.8 The electrical gap between charged bodies or between charged bodies and grounding in secondary circuits of 400 volts and below shall not be less than 4 mm.. The leakage distance should not be less than 6 mm.
2.9 Wires used to connect movable parts (door appliances, console boards, etc.) shall meet the following requirements:
2.9.1 Multi-stranded flexible wires shall be adopted, and proper redundancy shall be provided when laying.
2.9.2 The wiring harness shall have reinforced insulation layer (such as plastic pipe, etc.).
2.9.3 When connecting with electrical appliances, the ends shall be twisted tightly and shall not be loose or broken.
2.9.4 At both ends of movable parts, clips shall be used to fix them.
2.10 Control cables and their cores in imported panels and cabinets shall meet the following requirements:
2.10.1 Cables imported from panels and cabinets should be arranged neatly to avoid crossing, and should be fixed firmly to prevent the connected terminal board from being subjected to mechanical stress.
2.10.2 The steel belt of armored cable should not enter the panel and cabinet; The end of the armored steel belt cut should be fastened;
2.10.3 For the control cable used for transistor protection, control and other logic circuits, when shielded cable is used, its shielding layer shall be grounded; If shielded cable is not used, the base spare core wire should be grounded;
2.10.4 Rubber insulated core wire shall be protected by insulating tube;
2.10.5 Cable cores in panels and cabinets shall be regularly arranged vertically or horizontally, and shall not be arbitrarily askew and cross-connected; Spare cores shall have proper redundancy.
2.11 Where the insulated conductor may be corroded by oil, oil-resistant insulated conductor shall be adopted or oil-proof measures shall be taken.
2.12 Safety technical requirements for power distribution equipment:
2.12.1 When there are two or more power supplies, an interlocking device shall be installed between the main inlet of each power supply and the contact switch (except those dispatched by the power supply department).
2.12.210 kV indoor complete sets of equipment should be equipped with interlocking devices between the disconnector and the corresponding one.
2.12.3 The phase and color arrangement of power distribution equipment shall meet the requirements of the column:
(1) The phase and color arrangement of each circuit in the same power distribution device should be consistent as far as possible.
(2) The hard bus bar shall be painted, and its color is: phase A * *; B phase green; C phase red; The zero line is black.
(3) The flexible bus shall be marked with the phase difference.
(4) The wires in the interval of the power distribution device should have the position where temporary grounding wires are hung, and the phase paint should not be painted here.
2.13 The installation of terminal board shall meet the following requirements:
2.13.1 The terminal board shall be undamaged, firmly fixed and well insulated.
2.13.2 The terminal board shall be easy to replace and connect.
2.13.3 If the loop voltage exceeds 400 volts, the terminal board shall be sufficiently insulated and painted with a red sign.
Step 3 check
3.1 inspection
3.1.1 Whether the ventilation, lighting and safety fire prevention devices in the high and low voltage distribution room are normal.
3.1.2 The switchboard door shall be tight without damage, and the switchboard shall be clean and free of dust.
3.1.3 All power distribution panels in the station must be listed as a warning.
3.1.4 The signal lamps, electric bells and accident electric bells of the signal device loop shall be displayed accurately and work reliably.
3.1.5 Whether the voltage and current of the motor in the power distribution cabinet are normal (not exceeding 5% of the rated value).
3.1.6 Whether the bus bar and each contact are overheated, whether the temperature-indicating wax sheet is melted, and whether the insulating bakelite is burnt out.
3.1.7 Whether there are any abnormal smells and sounds in the operation of the electrical components in the switch cabinet.
3.1.8 Whether the oil level of the oiling equipment is normal, whether the oil color becomes darker and whether there is oil leakage.
3.1.9 Instruments, signals, indicator lights and other indications are correct, and the position of relay protection linking piece is correct.
3.1.10 and dc equipment operation are in good condition.
3.1.11 Whether the connecting wires of grounding and zero connection devices are loose or broken.
3.1.12 Whether the insulation of porcelain insulator, insulating sleeve and wall bushing is clean, and whether there are any broken cracks and discharge traces.
3.1.13 Whether the mechanical interlocking of circuit breaker and disconnector is flexible and reliable. If electromagnetic interlocking device is adopted, it is necessary to electrify to check whether the electromagnetic lock is flexible and accurate.
3.2 monthly inspection
Every month, make a comprehensive inspection of all operating parts and electrical parts of motors and power distribution cabinets, and conduct dynamic and closing tests of magnetic starters and sensitivity tests of relays.
3.3 annual inspection
Every three years, the relay test shall be conducted for the motor and distribution cabinet, which shall be verified by the power supply personnel.
3.4 Repair and maintenance
3.4.1 Repair and maintenance shall be conducted once a month.
3.4.1 Power outage maintenance lines must be listed before operation as a warning.
3.4.2 The motor, cable and distribution panel must be well grounded, and the grounding resistance should not be greater than 4 ohms.
3.4.3 Motor measures DC impedance and conducts AC withstand voltage test. Current sum for withstand voltage test and current ratio test.
3.4.5 Make DC withstand voltage leakage test for cables; Relay maintenance, reset.
3.4.6 The oil switch shall be disassembled for inspection, repair, adjustment and fastening; Lightning arrester for withstand voltage test.