DISTRIBUTION LINE FITTINGS

The EN 50423 standard outlines the general prerequisites for overhead lines spanning voltages from 1 to 45 kV. Medium-voltage lines utilizing bare conductors up to 45 kV adhere to the same guidelines as high-voltage lines. An alternative to bare overhead line conductors is the utilization of “partly insulated medium-voltage systems,” which possess diminished electrical insulation compared to fully insulated conductors. These systems offer protection solely against accidental contact with other insulated overhead line conductors or grounded parts and do not ensure contact safety. Consequently, these conductors must be treated as bare overhead line conductors, necessitating full safety considerations. EN 50397, parts 1 to 3, delineate the requirements for both conductors and their fittings.

Advantages of insulated overhead lines over bare lines include:

• Reduced phase-to-phase distances due to individual conductor insulation.
• Narrower route widths in forested areas, minimizing the need for immediate vegetation removal.
• Less ice accumulation compared to bare conductor lines.
• Enhanced operational and supply safety, mitigating short circuits caused by falling debris and eliminating the immediate necessity for repair work.
• Decreased risks of impact damage from weather events like wind, ice, and snow.
• Capability to install new or additional conductor systems on existing structures using existing cross arms and insulators.
• Offset higher construction costs with reduced maintenance expenses, enhanced safety, and improved supply reliability.
• Lower construction costs by employing smaller, lighter cross arms, thereby reducing stress on support structures for optimized design.
• Insulated plastic-covered conductors safeguard wildlife and notably diminish wild bird fatalities.

For insulated lines, fitting designs for both suspension and tension clamps designed for bare conductors can be utilized. These fittings are installed over the conductor insulation, ensuring adequate electrical potential control. Special compression dead-end clamps are employed over the conductor insulation, forming a hermetically sealed connection with ground wire connecting bolts. Similarly, insulated waterproof piercing connectors, akin to those used in insulated low-voltage power networks, pierce the insulation for electrical joint connection. Insulated conductor arcing horns or earthing devices are affixed using insulation piercing connectors, crafted from corrosion-resistant aluminum alloys with specialized insulation piercing teeth for reliable electrical contact. The second connector cable channel diverts and connects the energy connection. Arcing horns or tap-off cables can be separately fixed using a nut connection.

Connector advantages include:

• Replaceability of the arcing horn without loosening the connector following a high-intensity short circuit event.
• Arcing horn designed for short-time current withstand of 10 kA.
• Certification and qualification of connectors for each cable application to meet network requirements.
• Facilitated connection installation via parallel movement of upper and lower connecting parts.
• Availability of connectors with protective insulated sleeves upon request.

For any requests, please contact KORUCU directly.