Why Are Electrical Transmission Line Hardware Fittings Very Important?

Concept and Function of Electrical Transmission Line Hardware Fittings

Electrical transmission line hardware fittings generally refer to iron or aluminum metal accessories that connect and combine various devices in the power system, to transmit mechanical and electrical loads and serve as a protective function. Electrical transmission line hardware fittings are used on transmission lines to support, fix, and join bare conductors, as well as to connect insulators in strings. They are also used to protect conductors and insulators. There are numerous types of electrical transmission line hardware fittings, each with different functions. For instance, various clamps for installing conductors, various rings for forming insulator strings, various compression tubes and repair tubes for connecting conductors, and various types of spacers on split conductors, among others. Additionally, there are various guy wire fittings used on poles and towers.

Most electrical transmission line hardware fittings need to withstand significant tensile forces during operation, and some must also ensure good electrical contact. They are related to the safety of the conductors or towers, and even a single damaged fitting could cause a line fault. Therefore, the quality of electrical transmission line hardware fittings, their correct use, and installation have a crucial impact on the safe transmission of power along the line.

Classification and Uses of Electrical Transmission Line Hardware Fittings

According to their main performance and uses, electrical transmission line hardware fittings can generally be divided into suspension fittings, anchoring fittings, connection fittings, splicing fittings, protective fittings, fixation fittings, rigid jumper fittings, and cable fittings.

Suspension Fittings

Suspension fittings, also known as support fittings or suspension clamps, are mainly used to hang the conductor insulator strings (mostly used on straight-line towers or straight-line transposition towers) and to hang jumpers on the insulator strings.

Anchoring Fittings

Anchoring fittings, also known as fastening fittings or tension clamps, are mainly used to fasten the conductor's end, fixing it on the tension insulator string. They are also used for fixing the ground wire's end and for anchoring the guy wires. Anchoring fittings bear the full tension of the conductors and ground wires, and some also function as conductors. Based on the different structures and installation methods, they are divided into bolt type and compression type:

• Inverted Bolt Type Tension Clamp (NLD): The primary feature of the inverted bolt type tension clamp is the friction effect generated by the vertical pressure of the U-shaped bolt and the wave-shaped groove of the clamp to fix the conductor. Applicable range: aluminum strands wrapped with aluminum tape, steel-core aluminum strands (used in rural networks, substations, etc.).

• Compression Type Tension Clamp (NY): The primary feature of the compression type tension clamp is that it is composed of an aluminum tube and steel anchor. The steel anchor is used to connect and anchor the steel core of the steel-core aluminum strand. Then the aluminum tube body is fitted over it, and pressure is applied to cause plastic deformation of the metal, thereby combining the clamp and conductor into one unit. Applicable range: large-section steel-core aluminum strands, aluminum alloy strands, expanded conductors, heat-resistant conductors, etc.