STACIR/STACIR-AW Invar-Reinforced Conductor
STACIR conductor combines super thermal-resistant aluminium-alloy outer wires with an Invar-based reinforcing core, commonly supplied with an aluminium-clad surface in the available construction. The core’s relatively low thermal expansion is the central feature used to control high-temperature elongation and sag. It is not a gap-type conductor.
Key Advantages
- Low-expansion core: Invar-based reinforcement limits core thermal elongation.
- Thermal-resistant outer layer: Alloy strands provide the principal current path at elevated temperature.
- Clearance-focused design: Sag-tension modelling uses the exact core and conductor construction.
Product Overview
STACIR’s technical logic begins with its Invar-based core. Compared with conventional reinforcing steel, Invar has a lower coefficient of thermal expansion, so the core can reduce the growth in conductor length as temperature rises after load transfer. The aluminium cladding changes the core surface but does not replace the Invar mechanical function.
Low expansion does not mean zero sag. Final clearance depends on core area, conductor tension, knee-point behaviour, creep, installation temperature, spans and mechanical history. STACIR/TW, if offered, also changes the outer-wire geometry and should be treated as a separate compact-conductor design.
Key Features
- Super thermal-resistant aluminium-alloy wires form the main conductive section.
- An Invar-based reinforcing core provides a lower-expansion mechanical path than conventional steel.
- Aluminium cladding on the core creates a specific surface and corrosion interface that must be identified.
- Sag performance is project-specific and must be supported by approved stress-strain, creep and sag-tension data.
Product Applications
- Transmission-line uprating where high-temperature clearance is the principal constraint
- Reconductoring projects requiring evaluation of a low-expansion reinforcing core
- Existing corridors where thermal capacity and sag control must be assessed together
Technical Specifications
STACIR — Super Thermal Resistant Aluminum Alloy Conductor, Aluminum Clad Invar Reinforced
| Conductor Size | Stranding | Cross-Sectional Area | Diameter of Complete Conductor | Weight | Rated Strength | DC Resistance @ 20°C | Current Capacity | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| No. of Wires | Wire diameter | STAL | Invar | Total | STAL | Steel | Total | |||||||||
| STAL | Invar | STAL | Invar | @ 85°C | @ 150°C | @ 210°C | ||||||||||
| (mm²) | (No.) | (No.) | (mm) | (mm) | (mm²) | (mm²) | (mm²) | (mm) | (Kg/Km) | (Kg/Km) | (Kg/Km) | (KN) | (Ω/Km) | (Ampere) | (Ampere) | (Ampere) |
| 200 | 30 | 7 | 2.60 | 2.60 | 159.28 | 37.17 | 196.44 | 18.20 | 439.31 | 265.01 | 704.32 | 65.38 | 0.1746 | 403 | 690 | 850 |
| 240 | 30 | 7 | 2.90 | 2.90 | 198.16 | 46.24 | 244.39 | 20.30 | 546.54 | 329.69 | 876.23 | 79.92 | 0.1403 | 460 | 794 | 980 |
| 300 | 30 | 7 | 3.20 | 3.20 | 241.27 | 56.30 | 297.57 | 22.40 | 665.47 | 401.43 | 1066.90 | 94.82 | 0.1153 | 518 | 901 | 1114 |
| 300 | 30 | 7 | 3.20 | 3.20 | 241.27 | 56.30 | 297.57 | 22.40 | 665.47 | 401.43 | 1066.90 | 94.82 | 0.1153 | 518 | 901 | 1114 |
| 380 | 26 | 7 | 4.00 | 3.10 | 326.73 | 52.83 | 379.56 | 25.30 | 902.22 | 376.73 | 1278.95 | 104.26 | 0.0866 | 612 | 1076 | 1335 |
| 380 | 26 | 7 | 4.00 | 3.10 | 326.73 | 52.83 | 379.56 | 25.30 | 902.22 | 376.73 | 1278.95 | 104.26 | 0.0866 | 612 | 1076 | 1335 |
| 480 | 26 | 7 | 4.50 | 3.50 | 413.51 | 67.35 | 480.86 | 28.50 | 1141.87 | 480.23 | 1622.10 | 132.42 | 0.0684 | 704 | 1253 | 1559 |
| 480 | 26 | 7 | 4.50 | 3.50 | 413.51 | 67.35 | 480.86 | 28.50 | 1141.87 | 480.23 | 1622.10 | 132.42 | 0.0684 | 704 | 1253 | 1559 |
| 520 | 45 | 7 | 3.70 | 2.47 | 483.85 | 33.54 | 517.39 | 29.61 | 1337.00 | 239.17 | 1576.17 | 113.10 | 0.0597 | 748 | 1336 | 1665 |
| 520 | 45 | 7 | 3.70 | 2.47 | 483.85 | 33.54 | 517.39 | 29.61 | 1337.00 | 239.17 | 1576.17 | 113.10 | 0.0597 | 748 | 1336 | 1665 |
| 590 | 54 | 7 | 3.50 | 3.50 | 519.54 | 67.35 | 586.89 | 31.50 | 1437.04 | 480.23 | 1917.27 | 150.84 | 0.0549 | 790 | 1419 | 1771 |
| 600 | 54 | 7 | 3.53 | 3.53 | 528.49 | 68.51 | 596.99 | 31.77 | 1461.78 | 488.50 | 1950.28 | 152.20 | 0.0540 | 797 | 1434 | 1791 |
| 630 | 54 | 19 | 3.63 | 2.18 | 558.85 | 70.92 | 629.77 | 32.68 | 1545.78 | 507.40 | 2053.17 | 163.93 | 0.0511 | 824 | 1486 | 1857 |
| 690 | 54 | 7 | 3.80 | 3.80 | 612.42 | 79.39 | 691.81 | 34.20 | 1693.95 | 566.08 | 2260.03 | 176.38 | 0.0466 | 869 | 1576 | 1972 |
| 710 | 54 | 19 | 3.85 | 2.31 | 628.65 | 79.63 | 708.27 | 34.65 | 1738.82 | 569.72 | 2308.54 | 182.37 | 0.0454 | 883 | 1602 | 2006 |
| 730 | 45 | 7 | 4.40 | 2.90 | 684.24 | 46.24 | 730.48 | 35.10 | 1890.75 | 329.69 | 2220.44 | 155.82 | 0.0423 | 914 | 1663 | 2084 |
| 770 | 54 | 7 | 4.00 | 4.00 | 678.59 | 87.96 | 766.55 | 36.00 | 1876.95 | 627.24 | 2504.19 | 193.40 | 0.0421 | 922 | 1682 | 2108 |
| 800 | 54 | 19 | 4.09 | 2.45 | 709.47 | 89.57 | 799.04 | 36.79 | 1962.37 | 640.86 | 2603.23 | 205.51 | 0.0403 | 946 | 1729 | 2169 |
| 900 | 54 | 19 | 4.34 | 2.61 | 798.85 | 101.65 | 900.50 | 39.09 | 2209.60 | 727.30 | 2936.90 | 230.40 | 0.0357 | 1014 | 1868 | 2348 |
STACIR/TW — Shaped Wire
| Conductor Size | Cross-Sectional Area | Stranding | Diameter of Complete Conductor | Weight | Rated Strength | DC Resistance @ 20°C | Current Capacity | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| STAL | Invar | Total | No. of STAL Wires | No. of STAL Layers | No. of Invar Wires | Dia. of Invar Wires | STAL | Invar | Total | |||||||
| @ 85°C | @ 150°C | @ 210°C | ||||||||||||||
| (mm²) | (mm²) | (mm²) | (mm²) | (No.) | (No.) | (No.) | (mm) | (mm) | (Kg/Km) | (Kg/Km) | (Kg/Km) | (KN) | (Ω/Km) | (Ampere) | (Ampere) | (Ampere) |
| 320 | 322.26 | 52.49 | 374.75 | 20 | 2 | 7 | 3.09 | 22.88 | 888.49 | 374.31 | 1262.80 | 100.95 | 0.0876 | 596 | 1039 | 1287 |
| 340 | 336.85 | 54.90 | 391.75 | 20 | 2 | 7 | 3.16 | 23.38 | 928.73 | 391.46 | 1320.19 | 105.55 | 0.0838 | 612 | 1069 | 1324 |
| 390 | 389.25 | 50.81 | 440.06 | 20 | 2 | 7 | 3.04 | 24.72 | 1073.18 | 362.29 | 1435.47 | 109.47 | 0.0731 | 662 | 1163 | 1442 |
| 405 | 402.83 | 52.15 | 454.98 | 20 | 2 | 7 | 3.08 | 25.14 | 1110.62 | 371.89 | 1482.51 | 112.86 | 0.0706 | 676 | 1189 | 1475 |
| 480 | 479.69 | 47.20 | 526.89 | 35 | 3 | 7 | 2.93 | 26.98 | 1329.03 | 336.55 | 1665.58 | 123.00 | 0.0600 | 733 | 1298 | 1613 |
| 490 | 489.57 | 63.55 | 553.13 | 24 | 2 | 7 | 3.40 | 27.70 | 1349.78 | 453.18 | 1802.96 | 136.19 | 0.0581 | 759 | 1347 | 1676 |
| 525 | 523.67 | 26.85 | 550.53 | 30 | 3 | 7 | 2.21 | 27.50 | 1450.88 | 191.47 | 1642.35 | 107.39 | 0.0556 | 763 | 1354 | 1685 |
| 590 | 586.76 | 41.28 | 628.03 | 33 | 3 | 7 | 2.74 | 29.40 | 1625.66 | 294.31 | 1919.97 | 131.16 | 0.0494 | 820 | 1464 | 1825 |
| 625 | 625.07 | 79.63 | 704.69 | 38 | 3 | 19 | 2.31 | 31.32 | 1731.79 | 569.72 | 2301.51 | 177.43 | 0.0458 | 862 | 1549 | 1935 |
| 640 | 636.97 | 44.03 | 681.00 | 35 | 3 | 7 | 2.83 | 30.60 | 1764.78 | 313.97 | 2078.75 | 141.60 | 0.0455 | 860 | 1542 | 1925 |
| 680 | 676.24 | 85.95 | 762.20 | 39 | 3 | 19 | 2.40 | 32.58 | 1873.58 | 614.97 | 2488.55 | 191.75 | 0.0423 | 903 | 1630 | 2037 |
| 690 | 688.96 | 47.52 | 736.48 | 36 | 3 | 7 | 2.94 | 31.80 | 1908.82 | 338.85 | 2247.67 | 151.77 | 0.0421 | 899 | 1620 | 2024 |
| 725 | 725.09 | 91.78 | 816.87 | 39 | 3 | 19 | 2.48 | 33.72 | 2008.91 | 656.66 | 2665.57 | 205.21 | 0.0395 | 940 | 1703 | 2131 |
| 730 | 726.41 | 91.78 | 818.19 | 39 | 3 | 19 | 2.48 | 33.75 | 2012.56 | 656.66 | 2669.22 | 205.41 | 0.0394 | 941 | 1705 | 2134 |
| 740 | 737.40 | 51.14 | 788.54 | 36 | 3 | 7 | 3.05 | 32.92 | 2043.02 | 364.68 | 2407.70 | 162.72 | 0.0393 | 936 | 1692 | 2117 |
| 780 | 776.92 | 98.56 | 875.49 | 39 | 3 | 19 | 2.57 | 34.90 | 2152.52 | 705.18 | 2857.70 | 218.33 | 0.0368 | 979 | 1780 | 2231 |
| 790 | 789.13 | 54.55 | 843.69 | 36 | 3 | 7 | 3.15 | 34.05 | 2186.36 | 388.98 | 2575.34 | 173.95 | 0.0367 | 973 | 1767 | 2213 |
| 820 | 821.87 | 108.79 | 930.65 | 39 | 3 | 19 | 2.70 | 36.00 | 2277.05 | 778.33 | 3055.38 | 235.56 | 0.0348 | 1012 | 1847 | 2316 |
| 840 | 839.80 | 58.07 | 897.88 | 36 | 3 | 7 | 3.25 | 35.14 | 2326.74 | 414.07 | 2740.81 | 185.14 | 0.0345 | 1008 | 1837 | 2304 |
| 880 | 876.90 | 111.22 | 988.11 | 42 | 3 | 19 | 2.73 | 37.10 | 2429.50 | 795.72 | 3225.22 | 246.40 | 0.0326 | 1050 | 1923 | 2414 |
| 890 | 891.08 | 61.70 | 952.78 | 42 | 3 | 7 | 3.35 | 36.18 | 2468.81 | 439.95 | 2908.76 | 195.42 | 0.0325 | 1043 | 1907 | 2394 |
| 900 | 901.93 | 73.54 | 975.47 | 42 | 3 | 19 | 2.22 | 36.70 | 2498.85 | 526.19 | 3025.04 | 213.21 | 0.0320 | 1054 | 1931 | 2425 |
| 980 | 976.36 | 123.77 | 1100.13 | 42 | 3 | 19 | 2.88 | 39.12 | 2705.08 | 885.56 | 3590.64 | 274.28 | 0.0293 | 1115 | 2056 | 2587 |
| 990 | 987.86 | 68.90 | 1056.76 | 42 | 3 | 7 | 3.54 | 38.10 | 2736.95 | 491.27 | 3228.22 | 217.12 | 0.0293 | 1105 | 2035 | 2560 |
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From Production to Delivery
From raw material preparation to final shipmen, every stage is caretuly controled to ensure consistent conductor quality, reliable pertormance,and sae delivery. Our roduction,
inspection, packaging, and logistics processes are managed in accordance with applicable standards and project requirements.
Production
The approved aluminium-clad Invar core and super thermal-resistant aluminium-alloy wires are produced separately, then concentrically stranded to the specified construction.
Inspection
Inspection verifies Invar-core designation, cladding condition, STAL wire dimensions, strand arrangement, finished diameter and catalogue parameters.
Packaging
Packaging controls winding tension and bend radius to protect the specialized core, outer alloy layers and finished conductor geometry.
Shipping
Shipment documentation links each drum to its STACIR construction, core type, approved sag-tension data and hardware schedule.
Frequently Asked Questions
How does an Invar core reduce STACIR thermal sag?
Invar expands less with temperature than conventional reinforcing steel. After the core carries the relevant mechanical load, its lower thermal elongation helps limit the conductor’s temperature-related length increase.
Does the aluminium cladding provide the low-expansion property?
No. The Invar substrate provides the low-expansion mechanical behaviour. Aluminium cladding forms the outer surface of the core wire and affects its electrical and corrosion interface.
Is STACIR suitable without a project-specific sag-tension model?
No. The model must use the exact conductor, core, stress-strain and creep data, installation condition, spans, tensions and temperature range. A generic HTLS curve is not adequate.
How is STACIR different from a gap-type GTACSR conductor?
STACIR relies on a low-expansion Invar-based core in a concentric construction. GTACSR relies on a designed grease-filled gap and a specialised load-transfer and installation process.
What fittings need special attention on a STACIR project?
Dead-ends and joints must match the specialised core and compression sequence; suspension clamps, dampers and spacers must also be checked for diameter, temperature, mechanical load and vibration duty.
Which evidence should support a claimed STACIR operating temperature?
Use approved conductor and component-wire data, thermal ageing or qualification evidence required by the specification, compatible hardware ratings and a line study covering current, weather and clearances.
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