Live-line working on distribution lines involves performing tasks on live equipment using insulating tools or an insulated boom truck. This operation requires skilled personnel who must follow proper procedures and wear appropriate protective gear. Ensuring good insulation protection, correctly installing and using shielding tools, and maintaining strict on-site supervision are essential to achieving safe and efficient operations.
**Preparation and Safety Before Work**
1. **Operator Assignment**
The live-line team leader should assign operators the day before the job. If an operator shows signs of fatigue or poor physical condition on the day of the work, they should be replaced or other suitable measures taken.
2. **Tool and Material Preparation**
- Insulation shielding tools and personal protective equipment (PPE) should be selected based on the job requirements.
- All tools, shielding equipment, and PPE should be sorted, inspected, and placed in designated tool bags for easy access.
3. **Loading**
When loading tools and materials, ensure proper classification to prevent damage such as collisions, scratches, or punctures to insulation tools and PPE.
4. **Storage**
- Choose a dry and cool storage area with moisture-proof sheets to protect insulating shields, PPE, and live-line rods.
- Ensure these items are kept away from other objects to avoid damage.
5. **Work Plan**
For simpler tasks, the plan can be made on the day of the work. For more complex jobs, the plan should be prepared one day in advance after thorough research and analysis.
6. **Job Briefing and Pre-Work Meeting**
- The team leader should conduct a pre-work meeting to explain the task, sequence of operations, roles, and safety precautions.
- Any doubts from workers should be addressed until they fully understand their responsibilities.
7. **Inspection of Tools and Equipment**
- Check for any loose parts, cracks, or damage to tools and insulation shielding equipment.
- High-voltage gloves and boots should be inflated to check for pinholes or defects.
8. **Preparation Before Climbing**
- On the ground, wear insulated clothing, boots, and a safety helmet.
- Carry insulating gloves and protective gloves in a specific bag.
- Ensure that seat belts and auxiliary ropes are easily accessible and properly carried.
9. **Insulated Boom Truck Setup**
Position the insulated boom truck according to the safety manual to best suit the job requirements.
**Working Steps and Safety Considerations**
1. **Inspect Components**
- Examine the base and upper part of poles for stability. Take preventive measures if needed.
- Observe the pole’s upper structure from the ground to determine the aerial work vehicle’s path.
2. **Move to Working Position**
- Operators must fasten their seat belts before entering the work bucket.
- Operate the aerial work vehicle carefully, avoiding obstacles like power lines.
- Pay attention to low-voltage lines when passing under grounding crossarms and verify power status.
3. **Electrical Inspection Requirements**
- Use a low-voltage tester to inspect low-voltage support structures.
- A high-voltage tester should be used for high-voltage crossarms, keeping the head 30 cm below the crossarm.
- If no voltage is detected, use a low-voltage tester for verification.
- Adjust the work bucket so that the operator maintains a safe distance from live conductors.
- If using foot grips, follow the same safety precautions.
**Lifting Tools and Insulation Shields**
1. **Install Nylon Sling**
- Secure the nylon sling at a position that doesn’t interfere with normal operations.
- Determine the lifting point based on the operator’s location and nearby facilities.
- Hang the sling at a height above the ground to avoid entanglement.
2. **Lift and Install Tools and Shields**
- Load tools and insulation equipment into designated lifting bags.
- Use insulated cranes or pulleys for lifting. Ensure items are lifted safely without tangling.
- Ground workers should monitor the lifting process.
- Deliver tools one by one between operators.
- Auxiliary workers on the pole must wear the same protective gear and remain attentive.
**Wearing Protective Gear and Installing Shields**
1. **Wear High-Voltage Insulating Gloves**
- Always check gloves before use and wear protective gloves over them.
- Put on and remove gloves in a safe area, keeping a safe distance from live components.
2. **Install Wire Shield**
- Choose an easy-to-nest position for the wire shield.
- Tie the shield with an insulated string to prevent slipping.
- Use barriers or blankets to isolate nearby cables or low-voltage lines.
- Install shields from the nearest conductor outward, starting from the lower layers for multi-layered systems.
3. **Shield Insulators**
- Use insulator covers or blankets, ensuring a 15 cm overlap with the wire shield and securing with an insulated rope.
- Install wire shields first, then insulator shields.
**Operating Principles**
1. **Follow Established Procedures**
- Live-line work must be done by at least two people with a supervisor present.
- Follow the standard steps for each task. If unclear, refer to similar procedures.
2. **Work Near Live Conductors**
- Apply the same shielding methods as during live-line work.
- Do not skip insulation protection based on assumptions.
3. **On-Site Monitoring**
- The monitor should observe all activities and provide timely guidance.
- If the team leader is absent, a ground supervisor must take over.
4. **Post-Operation Inspection**
- Immediately check each step after completion.
- Ensure all shielding devices are intact and recheck before moving to the next step.
5. **Work Duration**
- Keep live-line work sessions under 30 minutes, with adequate rest breaks. Rotate shifts if necessary.
**Removal of Insulation Shields**
1. **Remove Insulation Devices**
- Remove shields from under or beside the wire.
- For high-voltage blankets, first remove the clamp, then pull the blanket from the bottom.
- Turn the wire shield opening upward before removing it from below.
- Handle shields gently to avoid vibration or deformation.
- Remove shields starting from the farthest line toward the nearest.
- Remove upper layer shields before lower ones.
- First remove the insulator cover, then the wire shield.
2. **Lower Tools and Shields**
- Reinstall tools in the order of the tool bag and hoist them carefully.
- Monitor the nylon sling to avoid entanglement with other equipment.
**Workers Descend to the Ground**
1. **Return to Ground Level**
- After completing the work, recheck the upper part of the pole and the facility status.
- Confirm everything is in order before lowering the work bucket.
- Check jumpers and leads on poles with low-voltage lines.
2. **Finalize the Job**
- Inspect all shielding tools and safety equipment for damage.
- Ensure all workers are accounted for, clean up remaining materials, and clear the area around the pole.
From the 1960s to the early 1980s, live-line operations were introduced in the distribution network. However, due to a lack of proper personal protection and insulation tools, many accidents occurred, leading to service interruptions in some areas. Today, to enhance the reliability of power distribution, every utility company emphasizes live-line work, establishing or reorganizing specialized teams. Developing standardized procedures and continuously improving them is crucial for effective live-line management.
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