Precautions for Hoisting of Electrical Equipment

The following are the precautions that need to be strictly observed during the hoisting of electrical equipment, covering key links such as preliminary preparations, operation specifications, safety protection, and emergency handling to ensure the safe transportation and precise installation of the equipment:

I. Preliminary Preparation Stage

1. Scheme Formulation and Approval

   - **Special Scheme**: Formulate the "Special Scheme for Hoisting Operations" for equipment types (such as transformers, distribution cabinets, GIS equipment, etc.), clarify the hoisting method (truck crane/crawler crane/winch), the position of the equipment's center of gravity, the distribution of lifting points, the specifications of the ropes (the safety factor ≥ 6 times the rated load), and the emergency plan.

   - **Compliance Review**: The scheme needs to be reviewed by the technical director. For dangerous and large-scale projects exceeding a certain scale (such as hoisting of a single piece with a weight ≥ 10 tons or a height ≥ 20 meters), it needs to pass the expert demonstration and comply with the "Regulations on the Safety Management of Dangerous and Larger Sub-projects" (Order No. 37 of the Ministry of Housing and Urban-Rural Development) and the electrical industry standards (such as DL 5009.1 "Safety Work Regulations for Electric Power Construction").

2. Equipment and Site Investigation

   - **Equipment Inspection**:

     - Verify the weight, dimensions, and load-bearing parameters of the lifting lugs/lifting rings of the equipment (it is necessary to confirm with the manufacturer, and overloading is prohibited), and check whether the welding joints of the lifting lugs are cracked or rusted.

     - Add shock-proof packaging to precision equipment (such as intelligent electricity meter boxes, relay protection devices), and sensitive components need to be fixed to prevent displacement.

   - **Site Requirements**:

     - The hoisting area should be leveled and hardened, with a bearing capacity ≥ 20t/m² (the outriggers of the truck crane need to be padded with steel plates, and the thickness ≥ 20mm). There should be no high-voltage lines within 5 meters around (the safety distance from a 10kV line ≥ 6 meters, and from a 35kV line ≥ 8 meters).

     - Hoisting is prohibited in bad weather (wind speed > 10m/s, heavy rain, heavy fog). Sufficient lighting (illuminance ≥ 300lux) is required for night operations.

3. Selection and Inspection of Appliances

   - **Hoisting Tools**:

     - Steel wire ropes, shackles, slings, etc. need to have a factory certificate. Steel wire ropes are prohibited from use when the number of broken wires exceeds 10% or the wear reaches 7% of the diameter.

     - The model of the crane should match the weight of the equipment (the rated load needs to be greater than 1.2 times the sum of the weight of the equipment and the weight of the rigging). For example, a 10-ton crane should be selected for hoisting a 5-ton transformer.

   - **Protective Equipment**:

     - Operators should wear safety helmets (in line with GB 2811), anti-slip gloves, and reflective vests. For high-altitude operations (> 2 meters), safety belts should be fastened (hanging high and using low).

 II. Core Specifications for Hoisting Operations

1. Personnel Division of Labor and Signal Unification

   - **Position Configuration**: Designate 1 general commander (working with a certificate), 1 hoisting driver (with a special operation certificate), and 2 signalmen (double confirmation with two-way walkie-talkies + gesture signals). Single-person operation is prohibited.

   - **Signal Standards**: Adopt GB 5082 "Command Signals for Hoisting and Handling", clarify instructions such as "raise the hook", "lower the hook", and "stop". The walkie-talkie channel should be dedicated, and interference from irrelevant personnel is prohibited.

2. Lifting and Positioning of Equipment

   - **Center of Gravity Calibration**:

     - After the equipment is suspended, let it stand for 10 seconds and observe whether it is tilted (if the inclination angle > 5°, the lifting points need to be readjusted). Precision equipment needs to be equipped with a level gauge for real-time monitoring (the deviation ≤ 2mm/m).

     - For equipment with multiple lifting points (such as large transformers), it needs to be lifted synchronously, and the force difference of each lifting rope ≤ 10% of the rated load.

   - **Movement Control**:

     - When the equipment is 200mm off the ground, pause, check the force on the ropes and the braking system. After confirming that there is no problem, move it slowly, with a speed ≤ 0.5m/s.

     - When crossing obstacles, the vertical distance between the bottom of the equipment and the obstacles ≥ 500mm to avoid colliding with vulnerable parts such as the busbars of the switchgear and porcelain insulators.

3. Precise Positioning and Fixing

   - **Positioning and Installation**:

     - The spacing error of the pre-embedded bolts of the foundation ≤ 2mm. When the equipment is positioned, it should be aligned with the bolt holes, and it is prohibited to adjust by forced knocking (to prevent the equipment from deforming).

     - After the installation of the transformer and the distribution cabinet, a spirit level should be used for calibration (the transverse deviation ≤ 1‰, and the longitudinal deviation ≤ 1.5‰), and the anchor bolts need to be grouted and fixed for the second time.

   - **Temporary Fixing**:

     - Equipment that is not fully fixed needs to be temporarily tied with guy ropes (steel wire ropes with φ ≥ 12mm). There should be no less than 4 ropes for each piece of equipment, with an included angle of 45° - 60° with the ground, and the bearing capacity of the anchor point ≥ 1.5 times the weight of the equipment.

III. Key Points of Safety Risk Prevention and Control

1. Electrical Safety Isolation

   - The live equipment near the hoisting area needs to be powered off and tested for electricity, and a warning sign of "No Closing" should be hung. For operations of 10kV and above, an insulating fence needs to be set up (the distance ≥ 1.7 meters).

   - During the hoisting of the equipment, the steel wire ropes and the crane boom should maintain a safe distance from the live body (for 110kV ≥ 4 meters, and for 220kV ≥ 6 meters). Insulating baffles need to be added when necessary.

2. Fall Prevention and Collision Prevention

   - The high-altitude work platform (such as an aerial work vehicle) needs to be firmly fixed, and the height of the guardrail ≥ 1.2 meters. It is prohibited for personnel to stand within 2 meters above the equipment.

   - Plan the hoisting path in advance, remove the ground obstacles (such as cable trenches and scaffolding), set up a warning area (radius ≥ 1.5 times the height of the equipment), and non-operating personnel are prohibited from entering.

3. Emergency Handling Measures

   - Sudden Power Outage: Immediately activate the backup power source (such as a battery hydraulic pump), keep the boom braked, and evacuate the personnel to a safe area.

   - Rope Breakage: Immediately send an emergency stop signal, evacuate the surrounding personnel, reinforce with a spare sling and then slowly lower the equipment. Risky operations are prohibited.

 IV. Acceptance and Records

1. **Process Records**: Fill in the "Hoisting Operation Inspection Form", record the equipment model, weight, hoisting time, handling of abnormal situations, etc., and file it for at least 2 years.

2. **Final Inspection**: After the equipment is fixed, recheck the bolt torque (such as the torque of M12 bolts ≥ 75N·m) and the grounding connection (the grounding resistance ≤ 4Ω). There should be no shaking or abnormal noise during the trial operation.

V. Compliance Standards and Reference Documents

- **National Standards**: GB 6067.1 "Safety Regulations for Hoisting Machinery", GB 50148 "Code for Construction and Acceptance of Electrical Installations - Power Transformers, Oil-immersed Reactors, and Instrument Transformers"

- **Industry Specifications**: DL 5009.1 "Safety Work Regulations for Electric Power Construction - Part 1: Thermal Power Generation", DL/T 575.12 "Ergonomic Design Guidelines for Control Centers - Part 12: Equipment Hoisting"

By strictly implementing the above processes, the risk of equipment damage (controlling the collision rate < 0.5%) and the safety accident rate (the goal of zero casualties) can be effectively reduced, ensuring that the hoisting of electrical equipment meets the engineering requirements of "safety, precision, and efficiency". If it is necessary to formulate a special scheme for specific equipment (such as box-type substations, reactors), the equipment parameters can be provided for further refinement.