Overhead transmission lines rely heavily on high-performance insulators to deliver stable power across complex terrain. Among mainstream insulator solutions, double-shed (double umbrella) toughened glass insulators stand out for optimized anti-pollution performance, reliable mechanical strength and easy field inspection. Widely deployed for 110kV, 220kV and above AC overhead power networks, they are preferred for mountainous, fog-prone, moderate-pollution zones as well as line renovation & T-connection projects.
Double-shed glass insulators are cap-and-pin disc suspension units made of tempered glass, hot-dip galvanized iron cap and steel pin. The special dual-shed profile extends creepage distance without enlarging overall dimension, delivering better self-cleaning capability compared with standard single-shed glass insulators. As a professional glass insulator manufacturer, we supply 70kN, 100kN, 160kN, 210kN, 240kN, 300kN, 420kN, 500kN double-shed glass insulators.
The open dual‑shed structure increases total creepage distance, effectively resisting pollution flashover under fog, dust and light‑medium contamination. Rainwater can wash off surface contaminants, bringing good natural self‑cleaning performance. The shed geometry reduces ice‑bridging risk in icing‑prone mountain areas, lowering unexpected line tripping risks in bad weather.
Toughened glass features unique self‑indicating failure mode. Once insulation performance degrades, the glass shell will break automatically. Field crews can detect faulty units via simple visual inspection from ground or by binoculars. No offline insulation resistance testing is required, which greatly cuts inspection workload for mountain‑located transmission lines with poor access conditions.
For plateau mountain regions with strong UV radiation and large day‑night temperature swing, tempered glass maintains stable dielectric property against ultraviolet aging and thermal shock. Insulator string configuration can be adjusted according to altitude correction requirements for local power grid specifications.
Located in Zhaotong, Yunnan (Southwest China), this project is a critical regional grid reinforcement work, combining new‑built 220kV main transmission infrastructure and the 110kV Fenghua T‑off line. Typical project characteristics include:
- Mixed‑voltage operation: coexistence of 220kV main line and 110kV T‑connection branch, with straight towers, angle towers and tension towers of multiple specifications.
- Retrofit & existing corridor reuse: partial old towers and power channel reconstruction, mixing new and original line facilities.
- Harsh mountain operating environment: high altitude, frequent fog, large temperature variation, partial icing risk, moderate pollution level.
- Difficult field patrol: mountain terrain raises the requirement for simple, reliable onsite fault detection.
For this project, our factory supplied 70kN, 100kN, 160kN double‑shed glass insulators to match full working conditions:
- 70kN double‑shed units deployed for most suspension strings on the 110kV Fenghua T‑connection branch.
- 100kN insulators adopted for small‑angle tension sections of 110kV and partial suspension towers of 220kV circuits.
- Heavy‑duty 160kN double‑shed glass insulators configured for 220 kV large‑angle, tension and mountain long‑span sections.
Thanks to double‑shed anti‑pollution design and self‑break diagnostic property, the delivered insulators satisfy local plateau mountain climate and the project’s renovation‑oriented technical requirements, ensuring long‑term safe operation of the regional power grid.
Double‑shed toughened glass insulators are widely selected for below power‑grid scenarios worldwide:
- 110kV‑1000kV overhead transmission lines, new construction, renovation, T‑connection & π‑connection retrofit projects.
- Mountainous, foggy, inland moderate‑pollution zones, high‑altitude power corridors.
- Lines with limited maintenance access, where easy visual fault identification is prioritized.
- Suspension strings, tension strings, angle tower strings with different mechanical load demands.
Double‑shed toughened glass insulators balance anti‑pollution capability, mechanical robustness and maintainability. With complete load range covering 70kN,100kN,160kN and above, they deliver proven value for 110 kV, 220kV and above transmission construction and retrofitting projects. Supported by rich real‑world project references such as the Longxun‑Zhaotong transmission program, we provide standardized and customized double‑shed glass insulators complying with IEC & GB standards for global utility clients, EPC contractors and power grid investors.
