I. Cause Analysis

According to investigations, the areas where overhead lightning wires have disconnected are predominantly located in regions with high wind forces. The two main reasons for disconnections caused by wear on suspended line clamps are:

Relative Movement Due to Wind: The body of the suspended line clamp experiences relative motion with the hanging board due to wind forces, causing the hanging board to swing around the clamp's shaft at a small angle. Since the hanging board is relatively thin, this swinging action can create grooves, leading to a reduction in the cross-sectional area of the clamp's shaft. Once the grooves reach a certain depth, the weight of the lightning wire can cause the clamp's body to fall from the suspended line clamp, resulting in a disconnection and grounding incident.

Improper Clamp Size or Insufficient Tightening: If the suspended line clamp is too large or the lightning wire is not tightly secured, relative motion can occur between the wire and the clamp body under wind forces, causing wear on the lightning wire. In cases of strong wind or significant lightning currents, the wire may be snapped or burned, leading to similar disconnection incidents

II. Prevention Measures

Regular Inspections: The hanging board on the clamp's shaft is secured by a pin, which has a flat washer covering the connection area. If the washer is not removed, it can be difficult to detect wear on the clamp's shaft. Therefore, when checking for wear, it is essential to remove the pin and washer. Additionally, temporary measures should be implemented to prevent the lightning wire from falling during inspections.

Correct Clamp Sizing: To prevent wear on the lightning wire, select the size of the suspended line clamp based on the wire's cross-section. During installation, strictly adhere to process requirements for wrapping the aluminum-clad tape around the lightning wire and ensure the wire is tightly secured.

Design Considerations: In line design, while there are requirements for hardware load, other strength parameters may not be inspected. In areas with strong winds and significant wind drift, it is advisable to choose wear-resistant clamps (such as those made from various alloys) and clamps equipped with anti-drift components.

Maintenance Protocols: Regular maintenance, especially during major inspections, should be conducted according to established protocols. All types of suspended line clamps should be inspected as per regulations. The inspection of suspended line clamps is often overlooked in maintenance work. To improve management, establish records for sections prone to clamp wear, shorten inspection intervals, and increase inspection items for suspended line clamps during routine patrols.