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Installation and maintenance of AC/DC switchgear

Release time:

2025-07-04

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Abstract

Installation and maintenance of AC/DC head cabinets are crucial for ensuring the safe and stable operation of power systems. Below are AC/DC Head Cabinets Detailed steps and precautions for installation and maintenance:

I. Installation of AC/DC Head Cabinets

1. Equipment Arrival Inspection

Packaging and Appearance Inspection ：
Check if the equipment packaging is damaged, has dents, or water stains, and confirm that the equipment model and specifications match the contract.
Tools/Tasks : Packing list, manufacturer's drawings, design drawings.
Unpacking Inspection ：
Jointly with supervision, construction unit, and manufacturer, conduct unpacking inspection, verifying the bill of materials, certificate of conformity, and factory inspection report. If not installed immediately, rain protection measures should be taken and documented in storage.

2. Installation Environment Inspection

Confirming Handling Conditions ：
Ensure the handling passage height is ≥ cabinet height + 0.2m, and width is ≥ cabinet narrowest side + 0.5m, to avoid hitting walls or the ground.
Installation Site Requirements ：
- Temperature and Humidity: Ambient temperature 0~40℃, relative humidity ≤90%.
- Dust and Water Protection: No dust or moisture on the ground, cabinet protection rating IP54/IP65.
- Grounding and Fire Protection: Ensure reliable grounding system and complete surrounding fire-fighting equipment.

3. Foundation Construction and Positioning

Foundation Construction ：
Use No. 5 angle steel as the foundation, paint its surface with rust-proof paint, and keep it consistent with the cabinet color.
Positioning and Leveling ：
- Use an infrared rangefinder for line marking and positioning; foundation levelness error ≤1.5mm/m, verticality error ≤1.5mm/m.
- Secure the angle steel foundation with expansion bolts, with a gap of ≤2mm between the cabinet and the ground.

4. Equipment Wiring

Cable Insulation Test ：
Use a 1000V megohmmeter to test cable insulation resistance, requirement ≥500MΩ.
Cable Laying and Crimping ：
- Cables should be laid neatly without crossing, with consistent tying intervals, and sufficient bending allowance.
- Crimping Process ：
  - For cables above 6mm², crimp after nesting with OT/SC/cold-press terminals;
  - For cables 6mm² and below, use tinning process or terminal nesting.
- Fire Sealing : Seal cable entry/exit points with fire-retardant mud, ensuring a flat and smooth surface.

5. Installation Quality Inspection

Internal Inspection ：
- No metal debris remaining, cables securely fixed, no scratches on the surface.
- Check for phase-to-phase and phase-to-ground short circuits in cables (a multimeter continuity test without a continuous beep indicates pass).
External Inspection ：
- Cabinet verticality ≤1.5mm/m, joint between cabinets in a row ≤2mm, deviation ≤5mm.

II. Maintenance of AC/DC Head Cabinets

1. Routine Inspection Contents

Equipment Status Check ：
- Check the operating status of circuit breakers, fuses, and residual current devices.
- Observe whether instrument indicator lights and electrical wiring are abnormal.
Wiring and Grounding ：
- Check if cable and terminal connections are loose or corroded.
- Measure grounding resistance to ensure a reliable grounding system.
Environment and Safety ：
- Check for cabinet deformation, rust, water leakage, and dust accumulation.
- Confirm that fire-fighting equipment is complete and evacuation routes are clear.

2. Maintenance Frequency and Plan

Routine Inspection : At least once a month; frequency can be increased for high-risk equipment.
In-depth Maintenance ：
- Clean internal components, tighten screws, lubricate mechanical parts.
- Calibrate instruments and monitoring equipment to ensure measurement accuracy.
- Check the effectiveness of protective devices such as lightning arresters and overvoltage protectors.

3. Problem Handling and Rectification

Recording and Reporting ：
- Detailed records of inspection date, personnel, problems, and rectification measures.
- Equipment management department and on-site leadership jointly review and sign for confirmation.
Rectification Measures ：
- Determine the rectification deadline based on the severity of the problem, and the equipment management department will follow up with acceptance.
- Major issues must be reported to the supervisor and accountability pursued.

4. Safety Precautions

Power-off Maintenance ：
- Verify power off after shutdown, ensuring operation in a de-energized state.
- Isolate live and non-live areas, and set up warning signs.
Personal Protection ：
- Wear insulated boots and gloves, and have someone supervise when operating AC side vacuum circuit breakers.
Capacitor Discharge ：
- Before maintaining the capacitor cabinet, it must be grounded to discharge. Direct contact is strictly prohibited.

III. Key Processes and Standards

Cable Crimping ：
- Crimping length ≥ crimpable length, copper wire is clearly exposed, and the cable cannot be easily pulled out.
Fire Prevention and Sealing ：
- Cable entry and exit points are sealed with fire-resistant putty, with a smooth surface.
Temperature Rise Control ：
- When the rated current is applied, the temperature rise of the electrical components must not exceed the standard.
Insulation Requirements ：
- The insulation resistance of the positive and negative poles of the DC busbar to ground > 2MΩ.

The installation of AC/DC switchgear cabinets must strictly follow the design drawings and construction specifications to ensure that the wiring process, fire prevention and sealing, and equipment leveling meet the standards; maintenance requires regular inspections, cleaning, maintenance, and safe operation to ensure the long-term stable operation of the equipment. Combining the technical requirements in the knowledge base (such as insulation testing and temperature rise limits) and practical cases (such as dual-power supply in data centers) can effectively reduce the failure rate and extend the service life of the equipment.

If you are planning an electrical equipment project, please feel free to leave a message to inquire and obtain a professional selection scheme!

Key words:

What causes high temperatures inside the electrical panel?

Application scenarios and selection of AC/DC switchgear

Hunan Chengyuan Electrical CO.,LTD