How Composite Insulated Sleeves Can Subvert Traditional Ceramic Designs

2025-08-02 13:44:02

The power industry is undergoing a revolution in insulation materials - composite insulation sleeves are gradually replacing traditional porcelain sleeves due to their advantages of lightweight, pollution flashover resistance, and long service life. This article will analyze this technological change from three aspects: material comparison, performance advantages, and engineering cases, and attach actual application data of a mountainous substation.   

1. Traditional porcelain bushing vs. composite bushing: comparison of core performance

>Key breakthrough: The composite casing adopts a structure of silicone rubber umbrella skirt and epoxy resin core rod, combined with hydrophobic migration (HC level ≥ 3), to maintain high insulation performance in polluted and high humidity environments.   

2. Core technology analysis of composite casing

(1) Silicone rubber umbrella skirt: the key to anti pollution flash

-Hydrophobicity Transfer: Small molecules on the surface of silicone rubber migrate to the fouling layer, keeping the fouling still hydrophobic (HC3 level) and avoiding the formation of a conductive water film.   

-Anti UV aging: Adding nano alumina (Al ? O ∝) to keep the umbrella skirt elastic after 30 years of outdoor use.   

(2) Epoxy resin core rod: high mechanical strength

-Tensile strength ≥ 600MPa (porcelain only 80MPa), suitable for heavy ice and strong wind areas.   

-Anti brittle fracture of core rod: using glass fiber+epoxy resin winding process to avoid the risk of brittle fracture of ceramic sleeve.   

(3) Optimization of end fittings

-Crimping Technology: Avoiding the aging problem of adhesive in traditional adhesive ceramic sleeves.   

-Sealing design: Adopting triple sealing rings (O-ring+silicone seal+waterproof adhesive) to prevent the core rod from getting damp.   

3. Engineering case: Application of composite casing in mountainous substations

project background

-Location: 110kV substation in a southwestern mountainous area (altitude 1800m, annual thunderstorm days ≥ 90 days)

-Original problem: The porcelain bushing experiences 5 lightning strikes and 2 pollution flashes per year, resulting in high maintenance costs.   

modification scheme

Replace all with composite sleeves (model: FXBW-110/100)

Optimize the umbrella skirt structure (alternating large and small umbrellas, with a creepage distance of ≥ 31mm/kV)

Install online monitoring (monitoring leakage current, warning pollution level)

Improvement effect (5-year data)

>Conclusion: Composite casing exhibits excellent performance in high pollution and multiple lightning strike environments, and can significantly improve the reliability of the power grid.   

4. Future trend: Intelligent composite casing

-Self diagnostic function: Built in fiber optic sensor, real-time monitoring of mechanical stress and leakage current.   

-Self cleaning coating: photocatalytic nano TiO ? coating, decomposes surface dirt.   

-Environmentally friendly materials: No SF ? design, in line with the trend of carbon neutrality.   

5. Selection suggestion: When to choose composite casing?   

Ultimate suggestion:

-New construction project: Prioritize the use of composite casing (with lower lifecycle costs).   

-Old renovation: gradually replacing ceramic sleeves, especially suitable for areas with high incidence of pollution and lightning strikes.   

conclusion

Composite insulation sleeves are replacing traditional porcelain sleeves globally due to their advantages of lightweight, stain resistance, and long lifespan. With the addition of intelligent monitoring technology, the insulation system of the future power grid will be safer, more efficient, and environmentally friendly.