GTACSR & GZTACSR Gap-Type HTLS Conductor
GTACSR and GZTACSR are gap-type HTLS (High Temperature Low Sag) conductors. The unique gap structure separates mechanical load and electrical function. Steel core bears all tension while aluminium expands freely inside the gap at high temperature. Widely used to upgrade existing ACSR transmission lines project without tower modification.
What is GTACSR / GZTACSR HTLS Conductor
GTACSR (full form Gap-Type Thermal-Resistant Aluminum Conductor Steel Reinforced) and GZTACSR (full form Gap-Type Super Thermal-Resistant Aluminum Conductor Steel Reinforced) are advanced HTLS overhead conductors designed for high-capacity power transmission. Featuring a high-strength steel core, thermal-resistant aluminum alloy strands, and a specially designed grease-filled gap, these conductors minimize thermal sag while maintaining excellent mechanical strength. They are ideal for upgrading existing transmission lines, increasing current-carrying capacity, and supporting high-voltage power grid projects.
Gap conductor, a controlled gap between the thermal resistant aluminium layers and central steel core. At high temperature, aluminium expands freely into the gap; the steel core takes all tension, so sag stays low.
High-temperature performance: Designed for continuous operation at elevated temperatures, typically up to 150°C for GTACSR and 210°C for GZTACSR, depending on the conductor design and applicable specifications.
Low sag characteristics: The gap construction and independent core movement help control thermal expansion and minimize sag.
Increased current-carrying capacity: Thermal-resistant aluminum alloy strands allow higher ampacity than conventional ACSR conductors of comparable size under appropriate operating conditions.
High mechanical strength: The high-strength steel core provides the mechanical support required for overhead transmission applications.
Transmission line uprating: Suitable for upgrading existing overhead transmission lines to increase power capacity while potentially avoiding major tower modifications.
GTACSR and GZTACSR conductors are widely used in high-voltage transmission line upgrades, power grid expansion, renewable energy integration, and other utility-scale infrastructure projects where increased transmission capacity and controlled conductor sag are essential.
Specifications & Common Sizes
Critical Remark: The marked mm² value refers to nominal thermal resistant aluminium alloy cross-section only. Steel core area is not included. Below are the most popular sizes for export reconductoring projects:
| Size (Al Area, mm²) | Equivalent ACSR Code | Total Outer Diameter (mm) | Approx Continuous Ampacity @180℃ (A) |
|---|---|---|---|
| 130 | – | 14.5 | 420 |
| 150 | – | 15.8 | 470 |
| 175 | Lynx | 17.2 | 530 |
| 185 | Lynx | 17.8 | 560 |
| 240 | Hawk | 20.8 | 690 |
| 270 | – | 21.6 | 740 |
| 310 | Hen | 23.7 | 830 |
| 370 | Goose | 25.8 | 940 |
| 410 | Condor | 27.3 | 1020 |
| 430 | – | 28.2 | 1070 |
| 520 | – | 30.8 | 1240 |
| 540 | – | 31.5 | 1280 |
| 620 | – | 33.8 | 1420 |
Application Standards GTACSR and GZTACSR: IEC 62420, IEC 61089, ASTM B609, ASTM B856, BS EN 50182
- IEC 62420 (HTLS overhead conductors)
- IEC 61089 (Round wire concentric lay overhead electrical conductors)
GTACSR: ordinary steel core
GTACSR/AW: Aluminum-clad steel core, specially designed for coastal highly corrosive environments
Typical Applications
- Suitable for 66kV/110kV/220kV old project transmission line reconstruction and capacity expansion, photovoltaic and wind power transmission lines, and ordinary inland corridors; GTACSR/AW recommends coastal corrosion areas.
- Wind farm and solar power evacuation transmission lines
- River, highway and valley long-span crossings
- Urban grid capacity expansion with limited right-of-way
- Coastal corrosive environment: choose GTACSR/AW aluminium clad steel core type
Why Choose GTACSR and GZTACSR conductors
Advantages of GTACSR/GZTACSR: They utilize mature, modern technology and have a proven track record in numerous ZMS (zero-sag/low-sag) projects. Compared to carbon-core conductors (such as ACCC), they are more cost-effective. Furthermore, as they feature an equivalent outer diameter to standard ACSR conductors, they can serve as direct replacements without requiring any modifications to existing towers or poles.
Matching Hardware & Fittings
GTACSR / GZTACSR conductors require dedicated HTLS compression fittings. Standard ACSR hardware is NOT compatible. Our supporting hardware package includes:
- Double tension hardware set
- Suspension clamps for HTLS
- Compression splice joint set
- Vibration dampers
- Armor rods, spacer dampers and yoke plates All fittings are tested to match the mechanical and thermal performance of GTACSR conductors.