With the increasing load levels of distribution networks and the diversification of conductor materials, traditional clamps have gradually exposed deficiencies in contact reliability, installation consistency, and long-term operational stability. New tension clamps and matching connection fittings have effectively solved problems such as conductor stress relaxation, unstable electrical contact, and low construction efficiency through wedge structures, elastic compensation mechanisms, and material upgrades. This article will explain the structural characteristics, working principles, and applicable scenarios of C-Clamp Connectors, aluminum tension clamps (wedge type dead end clamps), and carbon fiber composite core conductor splice sleeves and ACCC dead-end clamps, providing reference for selection and application in distribution engineering.
C-Clamp Connector
Functional Positioning
The C-Clamp Connector is a non-load-bearing type connection fitting used in transmission and distribution systems. It can be used for connecting conductors of various materials and is a new energy-saving clamp that replaces existing non-load-bearing clamps (including parallel groove, special-shaped, wedge, insulated piercing connectors, and compression sleeves). The C-Clamp Connector is installed by ejection using special tools, which is convenient and reliable.
Material Structure of C-Clamp Connector
The C-Clamp Connector adopts an inclined wedge structure, consisting of an elastic C-shaped element and inner wedges with inclined grooves on both sides. When the inner wedge is pushed between two conductors and locked, the spring action of the C-shaped element can produce continuous pressure on the conductor, compensating for stress relaxation of the conductor and ensuring good electrical contact performance.
The C-shaped element is usually made of special aluminum alloy. Its elastic characteristics enable the clamp and conductor to form a "breathing-type" matching relationship, which can effectively compensate for stress relaxation generated during conductor operation, allowing the clamp and conductor to obtain constant contact force. After the bolt is installed in place, it maintains constant tension, serving as a safety positioning function.
C-Clamp Connector Installation
Taking the installation of a bolt-type C-Clamp Connector on insulated conductors as an example, the typical process flow is as follows:
Strip the insulation layer of the insulated conductor; the stripping length should be 5 cm longer than the clamp length.
Hang the C-shaped element and tap conductor on the main line, and insert the wedge block between the two conductors.
Insert the special bolt into the pre-drilled hole of the C-shaped element and connect it to the threaded hole of the wedge block. Use a socket wrench to tighten the bolt until the first nut breaks off automatically.
Wrap the clamp and the stripped portion of the insulated conductor with insulating self-adhesive tape, or protect the clamp with a clamp cover.
In engineering practice, the C-Clamp Connector can also be installed using special tools. After purchasing this clamp, the manufacturer will provide technical support and introduction to special tools. In addition to C-Clamp Connectors used for transmission and distribution line conductors, there are also insulated C-Clamp Connectors.
Aluminum Tension Clamp
Applicable Range of Aluminum Tension Clamp
The aluminum tension clamp (wedge type dead end clamp) is mainly suitable for 10 kV and below distribution lines, used for tensioning connections of aluminum stranded wire or aluminum conductor steel reinforced (ACSR). It is a key load-bearing fitting connecting overhead conductors to poles and towers.
Material Structure of Aluminum Tension Clamp
The main body of this type of clamp is made of high-strength, oxidation-resistant aluminum alloy material. The overall structure is a wedge clamping structure, which is convenient to install and reliable in stress bearing. At the same time, its structural design avoids hysteresis and eddy current losses, which has positive significance for energy-saving operation of distribution networks. The working principle is that the clamp grips the conductor (such as ACSR or AAAC), connects to the insulator through a U-shaped or ring-shaped connector, and then connects this assembly to the pole or tower, transferring the conductor's tension to the structure.
Installation of Aluminum Tension Clamp
Threading the Conductor
Thread the overhead conductor into the clamping cavity of the aluminum tension clamp in the specified direction, ensuring the conductor is positioned in the center of the clamp without deviation or twisting.
Installing the Wedge Block
According to the clamp structure requirements, slowly push the wedge block into the clamp body along the conductor direction. The wedge block's inclined surface should properly fit with the inner cavity's inclined surface of the clamp, avoiding reverse installation or misalignment.
Initial Positioning
Before the wedge block is fully in place, adjust the conductor axis so that the conductor and the clamp's stress direction remain consistent, preventing insufficient grip force or local conductor damage due to eccentric loading.
Tensioning and Locking
Tension the conductor. When the tension reaches the design value, continue pushing the wedge block to the specified position so that the wedge block automatically clamps the conductor under tension, achieving reliable locking.
Connecting Tower Fittings
Reliably connect the tail of the clamp to the insulator string or tower fittings, ensuring the connection point is flexible, stress is clear, and there is no jamming.
Technical Parameters and Selection Criteria
Taking the NXLH series aluminum tension clamps as an example, their applicable conductor specifications, main dimensions, and clamp grip force parameters have formed a serialized configuration that can cover common LJ and LGJ type conductors. During engineering selection, the conductor model, outer diameter, and required grip force should be carefully checked to ensure that the clamp grip force meets the line design tension requirements.
| Model | Applicable Conductor | Conductor Outer Diameter (mm) | Main Dimensions (mm) | Clamp Grip Force (kN) |
|---|---|---|---|---|
| NXLH-1-1-L | LJ70, LJ50 | 10.8 (9.0) | L₁: 230; L₂: 80; D₁: 17; D₂: 20 | 10.95 |
| NXLH-1-1-LG | LGJ70/10, LGJ50/8 | 11.4 (9.6) | L₁: 230; L₂: 80; D₁: /; D₂: / | 23.4 |
| NXLH-2-L | LJ120, LJ95 | 14.25 (12.48) | L₁: 240; L₂: 85; D₁: 17; D₂: 20 | 19.42 |
| NXLH-2-LG | LGJ120/7, LGJ95/15 | 14.5 (13.61) | L₁: 240; L₂: 85; D₁: /; D₂: / | 27.57 |
Note: Model designation meaning: N-Tension; X-Wedge; LH-Aluminum alloy; numbers after "-"-applicable conductor model; additional letter L-aluminum stranded wire, LG-aluminum conductor steel reinforced. Example: Model NXLH-1-1-L represents the NXLH series aluminum tension clamp, suitable for aluminum stranded wire LJ70 or LJ50.
Material Structure of Carbon Fiber Conductor Splice Sleeves and ACCC Dead-End Clamps
Carbon fiber conductors (such as JRLX/T [ACCC] type conductors) use carbon fiber composite materials as the load-bearing core, which have significant differences in stress mechanism and material characteristics from traditional aluminum conductor steel reinforced (ACSR). Therefore, their splice sleeves and dead-end clamps must adopt specialized structural designs to avoid damage to the composite core. They are mainly composed of internal threaded pull anchor, sleeve, internal cone external threaded core sleeve, external cone elastic core clamp, and liner.
Working Principle
During the installation process, the carbon fiber conductor composite core passes through the external cone elastic core clamp and enters the internal cone external threaded core sleeve. When the internal cone external threaded core sleeve and internal threaded pull anchor are gradually tightened, the conical structure generates radial clamping force, causing the external cone elastic core clamp to contract uniformly in the radial direction, thereby achieving automatic clamping and reliable locking of the composite core conductor.
The clamping method uses radially distributed force, effectively avoiding local concentrated stress and providing good protection for the carbon fiber composite core.
Installation of Carbon Fiber Conductor Splice Sleeves and ACCC Dead-End Clamps
The carbon fiber conductor splice sleeve consists of an internal threaded pull anchor, sleeve, internal cone external threaded core sleeve, external cone elastic core clamp, liner, etc. During installation, one end of the sleeve is connected to the internal cone external threaded core sleeve through the internal threaded pull anchor. The internal cone external threaded core sleeve is connected in the middle through the external cone elastic core clamp. The JRLX/T (ACCC) carbon fiber conductor composite core is threaded through the inside of the external cone elastic core clamp. Through radial force, the external cone elastic core clamp and internal cone external threaded core sleeve automatically clamp and lock the conductor composite core, connecting and fixing the JRLX/T (ACCC) carbon fiber conductor to the JRLX/T (ACCC) carbon fiber conductor dead-end clamp. Finally, through the internal threaded pull anchor, the JRLX/T (ACCC) carbon fiber conductor is connected and fixed to the pole or tower.
FAQ
Q: What are the main advantages of new tension clamps over traditional clamps?
A: Enhanced Reliability: Elastic compensation mechanisms compensate for conductor stress relaxation, maintaining constant contact force.
Better Installation Consistency: Wedge structures ensure uniform installation quality and reduce human error.
Improved Long-term Stability: Material upgrades and structural design provide better electrical contact and operational stability over time.
Q: What types of traditional clamps can the C-Clamp Connector replace?
A: Parallel groove clamps,Special-shaped clamps,Wedge clamps,Insulated piercing connectors,Compression sleeves.
Q: Why do carbon fiber conductors require specialized clamps?
A: Carbon fiber composite cores have significantly different stress mechanisms and material characteristics compared to traditional steel-reinforced conductors. Standard clamps can damage the composite core. ACCC clamps use radially distributed force to avoid local concentrated stress.
Q: What are common installation mistakes to avoid with wedge clamps?
A: A:Reverse installation of wedge block,Misalignment of wedge inclined surfaces,Off-center conductor positioning causing eccentric loading,Insufficient tension before locking,Twisted or kinked conductors.
