The High Strength 3 Hole Yoke Plate is triangular in shape with three high-precision hinge holes. It is integrally machined from high-strength low-alloy steel plate and hot-dip galvanized for corrosion protection. It is primarily used for critical functions such as insulator string parallel connection, load distribution, conductor suspension, tension transfer, and maintaining split spacing. In global power grid construction, especially in 110kV–500kV transmission lines and ±800kV UHVDC projects, the three-hole high-strength hinge plate has become a standard configuration hardware. Although its structure is simple, it plays multiple irreplaceable roles in line operation, including mechanical hub function, load distribution, safety redundancy, deviation compensation, and vibration and icing resistance.
In transmission lines, single-string insulators often cannot meet the mechanical strength requirements of long spans, heavy loads, icy areas, and high-wind areas. Therefore, a design of parallel double-string insulators is commonly used. In this case, a connecting plate with uniform stress distribution must be used to connect the two strings of insulators. The High Strength 3 Hole Yoke Plate triangular structure is the optimal structure for achieving even load distribution. The two holes at the bottom connect the left and right strings of insulators respectively, and the central hole at the top connects to the conductor or tower suspension point. The triangular structure naturally ensures that the tension on both sides is strictly distributed in a 1:1 ratio, preventing uneven load distribution such as overload on one side and no load on the other. Without a connecting plate, direct double-point suspension can easily lead to excessive stress on one string due to installation errors, tower deformation, and conductor sway, resulting in hardware deformation, insulator breakage, or even line breakage and tower collapse. The three-hole connecting plate forces balanced stress through a rigid structure, significantly improving the safety redundancy of the line. After parallel connection of two strings, the theoretical load-bearing capacity is nearly twice that of a single string. In areas with heavy icing, long crossings, and high altitudes, this combination method is the most economical and reliable reinforcement solution.
The High Strength 3 Hole Yoke Plate enables reliable articulation between multiple components in the entire transmission line mechanical system. A typical connection link is: tower crossarm mounting point → three-hole yoke plate → double-string insulator → clamp → conductor, or conductor → tension clamp → three-hole yoke plate → double-string insulator → tower tension mounting point. In this structure, the High Strength 3 Hole Yoke Plate provides a standardized articulation interface. All three holes are of standard diameter, perfectly matching UB mounting plates, ball-head mounting rings, right-angle mounting plates, DB mounting plates, and other hardware, achieving a gapless, non-jamming, and freely rotatable articulated structure. The yoke plate itself can deflect and tilt within a certain range to adapt to positional changes caused by conductor wind deflection, icing sway, and temperature expansion and contraction, avoiding stress concentration caused by rigid tension. It can be flexibly combined with different types of insulators, clamps, and mounting plates of different lengths, allowing multiple suspension schemes on a single line to use the same yoke plate, reducing the types of hardware and lowering project procurement and management costs. Triangular shapes are small, rigid, and do not take up lateral space, making them particularly suitable for scenarios where the crossarm of the iron tower is short and space is limited.
In 220kV and above voltage level lines, a two-split conductor structure is commonly used to improve transmission capacity, reduce corona loss, and minimize radio interference. The High Strength 3 Hole Yoke Plate is a key hardware component for achieving standardized two-split conductor arrangement. The center distance between the two bottom holes of the connecting plate is the design split spacing, which remains unchanged during long-term operation, ensuring that the distance between conductors meets electrical design requirements and preventing phase-to-phase short circuits and excessive corona caused by insufficient spacing. The top hole connects to the suspension hardware, and the two bottom holes connect to the clamps of the two sub-conductors respectively, enabling the two conductors to be simultaneously stressed and oscillated by a single suspension point. The triangular rigid structure effectively constrains the relative position of the two sub-conductors, preventing conductor entanglement and whiplash wear caused by wind vibration and secondary span oscillation.
In the on-site construction of transmission lines, achieving perfect alignment is difficult. During operation, issues such as foundation settlement, tower deformation, and conductor thermal expansion and contraction can arise. The triangular structure and hinged hole design of the High Strength 3 Hole Yoke Plate effectively absorb and compensate for various deviations. Problems such as tower hole misalignment, crossarm twisting, and asymmetrical hanging points can be automatically adapted through the hinged joints and angle adjustments of the connecting plate, without affecting the stress state of the insulator string. In summer, as the conductor elongates, and in winter, as it contracts, the connecting plate can swing up and down with the conductor, avoiding axial hard pulling that causes wear on the hardware. Construction workers can assemble the equipment smoothly at high altitudes without requiring extremely high precision alignment, significantly improving construction efficiency, reducing the risks of high-altitude operations and labor costs. Uniform stress and no forced alignment significantly reduce fatigue damage to insulators, tower hanging points, and conductor clamps, extending the overall system lifespan.
The High Strength 3 Hole Yoke Plate, though seemingly simple in structure, is a key component in power transmission systems, integrating mechanical connection, load distribution, safety redundancy, electrical optimization, and environmental adaptability. In practical applications, it plays a crucial role throughout the entire lifecycle of a power line, from construction and operation to maintenance and accident prevention. It not only ensures the reliable suspension of conductors and insulators but also directly impacts the safety and stability of the entire power grid, operation and maintenance costs, service life, and compliance with international engineering acceptance standards.
