Installation specifications for high and low voltage distribution cabinets

1. Inspection of preparatory work before installation

Before installation, the supervising engineer and the engineer from Party A shall check whether the access road is unobstructed. If necessary, the general contractor shall be required to build a simple transportation channel to connect with various installation points. The layout of the construction site shall meet the requirements of safe and civilized construction. At the same time, it is necessary to check the arrangement of construction equipment by the installation unit, supervise the installation unit to inspect the construction equipment, and ensure that it is in good condition. Before the high-voltage equipment arrives at the site, the distribution room, trench, and foundation channel steel should have been fully completed.

1) Distribution room

Distribution room: Before the construction of the distribution room, the detailed drawings required for building the distribution room should be submitted to the construction party (within 2 weeks after the contract is signed, the focus should be on confirming the customer's position, content, and completion time of the drawings). During the construction process of the distribution room, our technical personnel or cooperative units should supervise on site to avoid construction errors. (The construction of the distribution room will take about 2 weeks)

2) Foundation

The placement of channel steel should correspond to the reserved equipment air duct in the distribution room, and the minimum distance between the equipment and the wall should be clear (if the distance is too close, the cabinet door of the equipment cannot be opened). (The welding of channel steel takes about 2 days, and our technical personnel must be present for guidance.)

3) Equipment arrives at the site

If the distribution room and foundation are not built properly, the equipment should have a storage location (to prevent rain or provide necessary rainproof materials).

2. Installation

2.1 The doors and windows of each distribution room must be tight, and the room should be clean.

2.2 The installation of the distribution panel is stable. The connection between the internal equipment and various components is firm.

2.3 The grounding of panels and cabinets should be firm and good. Openable panels and cabinet doors equipped with electrical appliances should be reliably connected to the grounded metal frame with flexible wires.

2.4 The installation of terminal boxes should be firm, well sealed, and the installation position should be easy to inspect. When installed in rows, they should be arranged neatly.

2.5 The wiring inside the distribution panel should be horizontal and vertical, with no loose screws and good contact between the wire ends.

2.6 The components inside the disk are fixed reliably without looseness, and the contacts are free of oxidation and burrs

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2.7 The connectors of the secondary circuit should be made of copper products. Specific requirements for wiring:

2.7.1 The connection of electrical circuits (bolt connection, insertion, welding, etc.) should be firm and reliable.

2.7.2 The end of the cable core and the matched wire should be marked with their circuit number; The numbering should be correct, the handwriting should be clear and not easily faded.

2.7.3 Neat, clear, and aesthetically pleasing wiring; The wire insulation is good and undamaged.

2.7.4 There should be no joints in the wires inside the panels and cabinets.

2.7.5 The wiring on each side of each terminal board is generally one and should not exceed two.

The electrical gap between the charged parts of the secondary circuit with a voltage of 2.8 400 volts or below, or between the charged parts and the ground, should not be less than 4 millimeters. The leakage distance should not be less than 6 millimeters.

2.9 The wires used to connect movable parts (door appliances, control panel, etc.) should also meet the following requirements:

2.9.1 Multi strand flexible wires should be used, and there should be appropriate redundancy during installation.

2.9.2 The wiring harness should have a reinforced insulation layer (such as a plastic tube).

2.9.3 When connecting to electrical appliances, the ends should be tightly twisted and not loose or broken.

2.9.4 Fix the movable parts with clips at both ends.

2.10 Control cables and their core wires introduced into panels and cabinets shall meet the following requirements:

2.10.1 The cables introduced into the panels and cabinets should be arranged neatly, avoiding crossing, and fixed firmly to prevent mechanical stress on the connected terminal boards.

2.10.2 The steel strip of armored cables should not enter the panel or cabinet; The end of the cutting point of the armored steel strip should be tightly tied;

2.10.3 Control cables used for logic circuits such as transistor protection and control, when shielded cables are used, their shielding layer should be grounded; If shielded cables are not used, the backup core wire should have one grounding wire;

2.10.4 Rubber insulated core wires should be protected with insulation pipes;

2.10.5 The cable cores inside the panels and cabinets should be arranged vertically or horizontally in a regular manner, and should not be arbitrarily skewed or cross connected; The spare core should have appropriate margin left.

2.11 In areas where insulated wires may be corroded by oil, oil resistant insulated wires should be used or oil proof measures should be taken.

2.12 Safety technical requirements for distribution equipment:

2.12.1 When two or more power sources are used for power supply, interlocking devices should be installed between the main incoming and connecting switches of each power source (except for those dispatched by the power supply department).

2.12.2 An interlocking device should be installed between the isolation switch and the corresponding circuit breaker of the 10 kV indoor complete set of equipment.

2.12.3 The phase color arrangement of the distribution device shall comply with the following regulations:

(1) The phase color arrangement of each circuit within the same distribution device should be as consistent as possible.

(2) The hard busbar should be painted with a color scheme of yellow for phase A; B phase green; C-phase red; Zero line black.

(3) The phase of the flexible busbar should be indicated.

(4) The wires within the interval of the power distribution device should have a position for hanging temporary grounding wires, which should not be painted with phase colored paint.

The installation of terminal boards should meet the following requirements:

2.13.1 The terminal board should be undamaged, securely fixed, and have good insulation.

2.13.2 The terminal board should be easy to replace and wired.

2.13.3 For circuits with a voltage exceeding 400 volts, the terminal board should have sufficient insulation and be marked in red.

3 Inspection

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 distribution panel door shall be tightly sealed without any damage, and the interior of the distribution panel shall be clean and free of dust and soil.

3.1.3 All distribution panels inside the station must be labeled to indicate a warning.

The signal lights, bells, and accident clocks in the signal device circuit should display accurately and work reliably.

Check if the voltage and current of the motor inside the distribution cabinet are normal (not exceeding 5% of the rated value).

Whether there is overheating phenomenon in the busbar and each contact point, whether the temperature indicator wax is melted, and whether the insulation glue wood is burnt out.

3.1.7 Check for any abnormal odors and sounds in the electrical components of the switchgear during operation.

Whether the oil level of the oil injection equipment is normal, whether the oil color has darkened, and whether there is any oil leakage.

Whether the indications of instruments, signals, indicator lights, etc. are correct, and whether the position of the relay protection pressure plate is correct.

3.1.10 Check if the relay and DC equipment are operating properly.

Check for any looseness or breakage in the connection wires of the grounding and neutral devices.

3.1.12 Whether the insulation of porcelain bottles, insulation sleeves, wall sleeves, etc. is clean, and whether there are any damage, cracks, or discharge marks.

3.1.13 Check whether the mechanical interlocking of circuit breakers and isolating switches is flexible and reliable. If an electromagnetic interlocking device is used, it is necessary to power on to check whether the electromagnetic lock action is flexible and whether the opening and closing are accurate.

3.2 Monthly inspection

Conduct a comprehensive inspection of the operating and electrical parts of the motor and distribution cabinet once a month, as well as a dynamic closing test of the magnetic starter and a sensitivity test of the relay.

3.3 Annual inspection

Perform relay tests on the motor and distribution cabinet every three years and have them verified by the power supply personnel.

3.4 Maintenance and upkeep

3.4.1 Maintenance and upkeep should be conducted once a month.

3.4.1 When repairing power outage lines, it is necessary to hang tags first and then proceed with work to indicate a warning.

3.4.2 The motor, cable, and distribution panel must be well grounded, and the grounding resistance should not exceed 4 ohms.

3.4.3 Measure the DC impedance of the motor and conduct an AC withstand voltage test. Current transformers and voltage transformers shall undergo voltage withstand tests and current ratio tests.

3.4.5 Conduct DC withstand voltage leakage test on cables; Repair and reset the relay.

3.4.6 Oil switch inspection, repair, adjustment, and fastening; Conduct a voltage withstand test on the lightning arrester.