Hollow Pultruded Insulation Rod
1. Product Introduction
Hollow pultruded electrical insulation rods, commonly referred to as hollow FRP insulation tubes or epoxy fiberglass hollow pultruded cylinders, are manufactured using ECR glass fiber roving and continuous mat as reinforcing materials, combined with a high-temperature-resistant epoxy resin system. They are formed as hollow tubular insulation profiles through a continuous pultrusion process, serving as specialized lightweight insulated load-bearing substrates for the high-voltage power industry.
2. Production Process
The products are produced using an automated continuous pultrusion production line: fiberglass yarns are impregnated with epoxy resin – cured and shaped in a constant-temperature mold – continuously pulled out – and cut to fixed lengths. The hollow structure is formed in a single step without secondary bonding, resulting in a dense, delamination-free body with smooth inner and outer walls and stable dimensional accuracy.
3. Core Material Advantages
Excellent insulation performance: The epoxy resin insulating matrix offers high breakdown voltage and low partial discharge, with power-frequency withstand voltage meeting requirements, suitable for high- and low-voltage power transmission and distribution equipment.
Lightweight and high strength: The hollow structure significantly reduces weight – over 30% lighter than solid rods – while providing high tensile and flexural strength, with excellent resistance to bending and deformation.
Environmental and chemical resistance: Resistant to acids, alkalis, moisture, and SF₆ gas corrosion; UV-resistant; and free from cracking or chalking during long-term outdoor service.
Stress-crack resistance: Uniform glass fiber distribution ensures balanced internal stress, eliminating issues such as brittle fracture and longitudinal cracking common in conventional tubes.
Flexible custom dimensions: Inner/outer diameters, wall thickness, and overall length can be customized on demand; supports secondary processing including threading, drilling, cutting, and sanding.
4. Key Specifications
Material: ECR glass fiber + epoxy resin
Structure: Hollow tubular, uniform wall thickness
Standard outer diameter: 10 mm – 200 mm; inner diameter customizable
Standard length: 1 m – 12 m; can be cut as required
Voltage rating: Covers 10 kV to 1000 kV full voltage classes
Characteristics: Flame-retardant, low water absorption, good mechanical toughness
5. Primary Applications
Internal hollow core tubes for arresters: Insulating support skeleton for zinc-oxide surge arresters; a standard matching substrate.
Composite hollow post insulators: Support insulation tubes for high-voltage substations and converter stations.
Live-line insulating operating rods: Main body of insulation poles for high-voltage maintenance work; lightweight and portable.
Insulating supports for high-voltage switchgear and instrument transformers: Insulating bushings inside switchgear and ring main units.
High-voltage insulating brackets for photovoltaic and wind power systems.
