Lightning protection measures for distribution lines - Solutions - Huaqiang Electronic Network

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In low-voltage distribution networks, the average height of poles is generally lower than that of transmission lines. Additionally, the surrounding environment may be partially shielded by buildings and trees, which reduces the likelihood of lightning strikes. However, due to the relatively low insulation level of these networks, the close spacing between conductors makes them more susceptible to tripping when struck directly by lightning. As a result, it's essential to enhance the lightning protection measures for distribution systems in order to improve power supply reliability.

The fundamental technical measures for protecting distribution lines from lightning include:

Protection against direct lightning strikes: To increase the lightning resistance of distribution networks, it's important to raise the line’s insulation level. This can be achieved by using porcelain cross arms or high-performance insulators. Given the large number of distribution lines, their wide coverage, and long lengths, it's not cost-effective to install overhead ground wires or lightning rods for every line. In addition, since most distribution systems use an ungrounded neutral configuration with shorter spans, the conductors often form a triangular arrangement. In such cases, the top conductor can act as a natural lightning protection wire. Therefore, the most effective approach is to install grounded protective gaps on the insulators of the top conductor at regular intervals.

Protection against induced lightning: Distribution lines may have weak points in insulation, such as isolated metal towers, particularly tall structures, individual iron crossarms, or towers with guy wires and terminal poles. These areas should be equipped with surge arresters to provide additional protection against indirect lightning effects.

All electrical equipment along the distribution line—such as distribution transformers, circuit breakers, and isolators—should be protected according to their criticality. This includes the installation of surge arresters or protective gaps to ensure comprehensive protection and reduce the risk of damage from lightning strikes. A thorough and well-planned lightning protection strategy ensures that no vulnerable point is overlooked, significantly enhancing the overall resilience of the power distribution system.