Polymer insulators (composite insulators) offer significant advantages in terms of ease of installation and handling, primarily due to their lightweight insulator benefits. However, to ensure their long-term performance and prevent premature failure, it’s crucial to follow specific best practices during transportation, storage, and Polymer insulator installation.
1. Transportation and Storage:
- Careful Packaging: Polymer insulators should be shipped in crates or packaging designed to protect them from damage, particularly to the weathersheds and end fittings.
- Avoid Bending: While polymer insulators have some flexibility, excessive bending or reverse cantilever loading (bending against the shed direction) should be avoided as it can damage the FRP core or the interfaces. They should not be used as steps or supports.
- Proper Storage: Store insulators in their original packaging in a clean, dry area away from direct sunlight, extreme temperatures, and corrosive chemicals if long-term storage is needed. Although silicone rubber is UV resistant, prolonged unnecessary exposure is best avoided.
2. Handling On-Site:
- Minimize Shed Damage: The silicone rubber weathersheds are crucial for pollution performance. Avoid dragging insulators on the ground or allowing sharp objects (tools, tower members) to cut, gouge, or tear the sheds. Minor, superficial nicks may be acceptable, but deep cuts that expose the core are not.
- Lifting Slings: Use appropriate lifting slings made of soft materials (e.g., nylon) and ensure they are placed around the metal end fittings or designated lifting points, not directly on the sheds, to avoid concentrating stress on the polymer housing.
- Avoid Torsion: Do not subject the insulator to excessive torsional (twisting) loads, especially after it’s connected at both ends.
3. Installation Process:
- Visual Inspection: Before installation, visually inspect each insulator for any signs of damage to the housing, sheds, or end fittings that may have occurred during transit or handling.
- Correct Orientation: Ensure the insulator is installed in the correct orientation as specified by the manufacturer (e.g., “ground end” marking).
- Torque Specifications: When connecting to other hardware, adhere to the recommended torque specifications for bolts to avoid over-stressing the end fittings or connected components.
- Corona Rings: If corona rings are supplied (common for higher voltages), ensure they are installed correctly as per the manufacturer’s instructions. Improperly installed corona rings can be detrimental.
- Lightweight Advantage: The most significant benefit during polymer insulator installation is their light weight. This often allows for manual lifting and positioning, reducing the need for cranes or heavy equipment, especially in difficult terrain. This translates to faster installation times and reduced costs.
4. Live-Line Installation: Polymer insulators are well-suited for live-line installation (hot-line work) due to their light weight and ease of maneuverability. However, standard live-line work procedures and safety precautions must be strictly followed. Ensure tools used do not damage the insulator housing.
5. Post-Installation: After installation, perform a final visual check to ensure the insulator is hanging correctly and no damage occurred during the process.
By adhering to these handling composite insulators best practices, utilities can maximize the lifespan and reliability of their polymer insulator assets, fully realizing the benefits of this advanced insulation technology while avoiding insulator damage.
