Line fittings are accessories used to connect and combine various devices within the power system, either to transmit mechanical and electrical loads or to serve a protective function. These components, which include a variety of connectors, insulators, and support devices, are the backbone of any electrical grid, ensuring the stability and reliability of the transmission and distribution lines.
Functionality
Line fittings are designed to secure, support, and protect electrical conductors and cables. They facilitate the connection of various electrical equipment, such as transformers, switches, and meters, to the power lines. The primary functions of line fittings include:
- Mechanical Support: Providing physical support to conductors, ensuring they maintain the correct position and alignment.
- Electrical Insulation: Preventing electrical leakage and ensuring the safe transmission of power.
- Connection Points: Enabling the secure and reliable connection of different electrical components.
Types
The variety of line fittings available caters to different requirements of the electrical network:
- According to the function, performance and structure, it can be divided into suspension clamps, tension clamps, connectorfittings, splicing fittings, protective fittings, wire clamps, T-shaped clamps, busbar fittings, and stay wire fittings. (The following is a description of commonly used line fittings based on this classification.
- It can be used as line fittings and substation fittings according to its purpose.
- According to the unit of linefittings products, it is divided into four units: malleable cast iron, forging, aluminum-copper-aluminum, and cast iron.
- It can also be divided into national standard and non-national standard, which are commonly referred to as standard and non-standard fittings.
(1).Suspension clamps
Suspension clamps are the fittings used to suspend conductors (or ground wires) to the suspension insulator string (assembly) or the fitting string (assembly). The commonly used stereotyped product of suspension clamps now retains the U-bolt style fixed suspension (often called the boat-type clamp), which consists of a U-bolt hanger and a boat body. The other is the pre-tensioned suspension clamp.
U-bolt type suspension clamp
pre-tensioned suspension clamp
(2).Tension Clamps
Tension clamps are the fittings used to connect conductors (or ground wires) to a tension string (or assembly) or to a fitting string (or assembly).
Tension clamps can generally be divided into two main categories based on their structure and installation conditions:
The first category of tension clamps is designed to withstand the full tensile force of the conductor or ground wire. The clamp’s grip strength is not less than 90% of the rated tensile strength of the installed conductor or ground wire, but it does not serve as a conductor itself. These clamps can be removed and reused after the conductor is installed. This category includes bolt-type tension clamps and wedge-type tension clamps, among others.
bolt-type tension clamps
hydraulic tension clamps
The second category of tension clamps not only bears the full tensile force of the conductor or ground wire but also acts as a conductor. Consequently, these clamps cannot be dismantled once installed and are also known as dead-end clamps. As they are conductive, the installation of these clamps must be carried out strictly in accordance with the relevant installation operation procedures.
pre-tensioned tension clamps
(3).connector fittings
Connector fittings are the Fittings used to connect and assemble insulators, suspension clamps, tension clamps, and protective fittings into suspension or tension strings (assemblies).
Classification and Applications: U-bolts, two-link plates, right-angle hanging plates, extension rings, U-bolt screws, and other fittings are referred to as general fittings, used for connecting between insulator strings and fittings, between clamps and insulator strings, and between ground wires and transmission towers. Ball head hanging rings and bowl head hanging plates are special fittings for connecting with ball-and-socket type insulators.
(4).splicing fittings
Splicing fittings are used for the connection or repair of the conductors (or ground wires), and can meet certain mechanical and electrical performance requirements for the conductors (or ground wires).
splicing sleeve
(5).protective fittings
Protective fittings serve to protect the electrical or mechanical performance of conductors, ground wires, various electrical devices, or the fittings themselves.
stockbridge damper
spacer
counterweight
(6).stay wire fittings
Metal components that connect, secure, adjust, and protect guy wires from transmission towers to anchors, serving to connect guy wires and bear the tension forces.
UT-Type Eye Bolt
Wedge-type clamps
(7).busbarfittings
Fittings used for the fixation, suspension, and support of busbars.
Benefits
The use of line fittings offers numerous advantages for electrical networks:
- Enhanced Safety: Reduces the risk of electrical accidents by ensuring secure connections and proper insulation.
- Improved Reliability: Minimizes the chances of line failures due to the robustness of the fittings.
- Easy Maintenance: Facilitates easy inspection and replacement of components.
- Versatility: Suitable for various environments and applications, including overhead and underground installations.
- Longevity: Designed for durability to withstand harsh weather conditions and long-term use.
Technical Specifications
The technical specifications of line fittings are tailored to meet the specific needs of the electrical system:
- Material: Made from materials such as aluminum, copper, or composites, ensuring strength and resistance to corrosion.
- Voltage and Current Ratings: Compatible with the electrical system’s operating voltage and current.
- Temperature Range: Capable of withstanding the expected temperature variations in the installation environment.
- Mechanical Strength: Able to withstand the physical forces exerted on the electrical lines.
Structural Features
The structural features of line fittings are designed for optimal performance and ease of use:
- Robust Construction: Built to withstand the rigors of outdoor environments and long-term exposure to the elements.
- Easy Installation: Designed for quick and straightforward installation, reducing labor costs.
- Clear Markings: Provide information on the type, rating, and manufacturer of the fitting.
- Corrosion Resistance: Treated to resist corrosion and maintain integrity over time.
- Compatibility: Designed to be compatible with various types of conductors and support structures.
In conclusion, line fittings are indispensable in the electrical industry, providing a reliable and safe means of connecting and supporting electrical lines. Their versatility and robust design make them an ideal choice for maintaining the integrity and efficiency of power distribution networks in a wide range of assemblytings.
