Our Solution for the Iraq Central 400kV OHTL: Fog-Type Toughened Glass Insulators

Overview

This 400kV Double Circuit Overhead Transmission Line (OHTL) is a critical backbone power infrastructure project under Iraq Ministry of Electricity’s national grid reinforcement programme, located in central Iraq. The double-circuit 400kV overhead line forms a key segment of Iraq’s high-voltage transmission network, designed to strengthen the central power grid.

Iraq has long suffered from power shortages and ageing grid assets. This new 400kV double-circuit line is designed to boost bulk power delivery capacity, improve grid stability, reduce outages, and evacuate electricity from power plants to residential and industrial consumers across central Iraq. The double-circuit tower layout maximises power transfer capability while optimising land use and minimising right-of-way costs.

The project site features a harsh desert environment with heavy sand, alkaline dust contamination and large diurnal temperature fluctuations. These conditions impose strict requirements on insulator pollution resistance, mechanical strength and long-term operational reliability. Our company was selected as the glass insulator supplier for this landmark 400kV transmission project.

Project Challenges

• Severe desert pollution: Sand and salt-alkaline dust continuously accumulate on insulator surfaces, raising high risk of pollution flashover.
• Wide temperature cycling: Extreme day-night temperature variations demand stable insulation performance of glass insulators.
• Mixed mechanical loading conditions: Different tower types require differentiated insulator ratings: tangent towers carry regular static loads while angle and tension towers withstand heavy tensile loads.
• Field operation & maintenance constraints: Remote desert routes require simple, fast inspection methods for live-line maintenance crews.

Our Solution: U120BP & U160BSP Fog-Type Toughened Glass Insulators

We delivered IEC 60383 compliant fog-type toughened glass disc insulators, tailor-matched for different tower applications on this 400kV double-circuit line:

U120BP (120kN fog-type glass insulator)

Deployed for suspension strings on tangent towers. With fog profile and extended creepage distance, U120BP delivers excellent anti-pollution performance against desert dust. Rated 120kN mechanical failing load, it handles standard conductor loads reliably. A major advantage of toughened glass is visible self-shattering upon failure, so defective units can be easily identified during routine patrol without complex testing equipment.

U160BSP (160kN enhanced anti-pollution fog glass insulator)

Supplied for tension strings on angle towers, heavy-load sections and large crossing segments. With higher 160kN mechanical strength and optimised fog profile for longer creepage distance, U160BSP is engineered for high mechanical tension and severe contamination zones. It minimises flashover risk under heavy dust deposition, protecting the 400kV line during harsh desert weather.

The combination of U120BP and U160BSP creates a cost-effective, field-proven insulation solution widely adopted for Middle Eastern EHV overhead transmission projects.

Project Value & Benefits

• Enhanced grid reliability: Our fog-type glass insulators resist desert sand and alkali dust, reducing pollution flashover incidents for the 400kV backbone line.
• Easy field inspection: Toughened glass self-breakage characteristic simplifies patrol work and lowers long-term maintenance expenditure for Iraq’s power authority.
• Proven IEC standard compliance: All insulators passed full type tests in accordance with IEC 60305, meeting the strict technical specifications of Iraq Ministry of Electricity.
• Middle East reference project: This 400kV OHTL project serves as a valuable reference case for our high-voltage glass insulator solutions across Iraq and the broader MEA power market.

Conclusion

This 400kV double-circuit transmission line is a milestone upgrade of Iraq’s national power grid. By supplying U120BP and U160BSP toughened glass insulators, we provide robust, anti-contamination insulation technology that stands up to Iraq’s challenging desert operating environment. Our team continues to deliver trusted high-voltage insulator products and technical support for global EHV transmission line and substation projects.