Views: 0 Author: Site Editor Publish Time: 2025-07-22 Origin: Site
Ultra-high voltage (UHV) power transmission has revolutionized the global energy landscape by enabling long-distance and large-scale electricity delivery with minimal loss. UHV systems—those exceeding 800 kV AC or ±800 kV DC—are now essential for meeting the energy needs of growing cities and industries. However, these systems operate under extremely harsh electrical and environmental conditions, placing enormous demands on every component—especially the insulators.
Insulators are critical in maintaining the safe separation between conductive components and the external environment. A failure here can lead to flashovers, blackouts, and irreversible equipment damage. Among various material options, insulating silicone rubber has emerged as the superior solution for UHV insulator applications. At Hefeng Silicone, we specialize in manufacturing advanced insulating silicone rubber that provides excellent electrical performance, weather resistance, and long-term reliability. Understanding the role of this material is essential to making informed decisions in UHV system design and maintenance.
UHV insulators face far more complex and severe operating conditions compared to standard high-voltage systems. Understanding these challenges highlights why ordinary materials like glass and porcelain often fall short in these environments.
UHV lines deal with electric field gradients that are several times higher than conventional systems. These conditions lead to:
Partial discharge (PD): A localized dielectric breakdown that occurs within insulation defects or air gaps.
Corona discharge: Caused by ionization of the air around the conductor, leading to energy loss, audible noise, and UV emission that degrades surrounding materials.
Flashover risks: Inadequate insulation may lead to uncontrolled electrical discharge across insulator surfaces.
These phenomena accelerate the aging of insulators and compromise their safety margin if the insulation material is not resilient and consistent under voltage stress.
Environmental pollution is a major issue in both urban and coastal transmission routes:
Industrial particulates, road dust, and salt spray settle on the insulator's surface and, under wet conditions, form a conductive layer.
Leakage currents flow across the surface, generating heat and possibly triggering thermal breakdown or pollution flashover.
Dry band arcing may occur, gradually eroding the material and reducing performance.
An ideal UHV insulator material must not only resist contamination but also continue functioning despite it.
UHV insulators must endure a host of mechanical and weather-related stresses:
Wind load across vast conductor spans.
Thermal cycling, causing expansion and contraction in materials not designed for such conditions.
Seismic activity in fault-prone areas.
UV radiation, acid rain, snow, and high humidity, all of which impact insulator integrity over time.
Without a highly durable and flexible material, these combined stresses can cause cracking, delamination, or loss of insulating properties.
Silicone rubber, particularly the kind engineered by Hefeng Silicone for UHV applications, is not just a suitable choice—it is a purpose-built solution for harsh insulation environments.
Our insulating silicone rubber exhibits:
Dielectric strength above 20 kV/mm, far exceeding the stress levels found in UHV systems.
Stable dielectric constant and low dissipation factor across temperature and frequency variations.
Minimal permittivity drift over long-term exposure.
This allows it to reliably isolate live parts, even under surges or atmospheric disturbances.
Unlike porcelain or epoxy, silicone rubber has inherent hydrophobicity. Even when the surface is contaminated, water droplets do not form a continuous film. This prevents:
Surface current flow
Pollution-induced flashover
Energy loss due to leakage current
Moreover, when the surface temporarily loses hydrophobicity due to pollution, low-molecular-weight siloxanes migrate to the surface and restore the water-repellent function. This self-recovery mechanism significantly extends the operational life of the insulator.
Silicone rubber's molecular backbone (Si–O–Si) is extremely stable. Hefeng's silicone rubber:
Resists UV radiation without yellowing or cracking
Withstands acid rain, salt fog, and chemical fumes.
Is non-reactive to ozone, a common by-product of corona discharge.
This durability ensures low maintenance, even in highly corrosive industrial or coastal zones.
Composite insulators used in modern UHV systems depend heavily on the material used for their outer sheath. The silicone rubber housing protects the internal fiberglass core rod and enhances electrical performance.
Compared to traditional insulators:
Silicone composite insulators are up to 70% lighter, reducing tower and crossarm load.
Safer for handling during installation, especially in mountainous or remote areas.
Lower transportation and logistic costs.
In large-scale transmission projects, this difference translates into significant operational advantages.
Silicone rubber is highly moldable, allowing for:
Integrated sheds that provide high creepage distances and optimal self-cleaning shapes.
Improved aerodynamics that reduce wind-induced vibration.
Seamless housing designs that eliminate weak points in the insulator body.
Hefeng Silicone offers tailor-made insulating silicone rubber compounds based on customer mold designs and geometry requirements.
The tracking and erosion resistance of silicone rubber is critical to UHV safety. Our materials pass:
IEC 60587 1A 4.5 tracking & erosion tests
ASTM D2303 inclined plane method tests
IEC 61109 aging tests for composite insulators
These properties prevent surface damage under persistent electrical stress and pollution accumulation.
UHV infrastructure is capital-intensive. The longer the components last without maintenance, the better the return on investment. Insulating silicone rubber plays a major role here:
With permanent hydrophobicity and self-cleaning surface properties, silicone insulators:
Require fewer cleanings and inspections.
Lower maintenance frequency, even in high-pollution zones.
Maintain performance under extreme weather events.
This reduces system downtime and associated labor costs.
Studies and field data show that silicone rubber insulators maintain stable electrical and mechanical performance for 25–30 years in service, even under pollution and harsh climates.
Aging simulations confirm minimal reduction in tensile strength or dielectric values.
No delamination or structural failure in properly compounded and molded materials.
Hefeng Silicone ensures that every batch of insulating silicone rubber undergoes rigorous mechanical, electrical, and weathering tests before delivery.
Our silicone formulations bond well with fiberglass rods and metal end fittings used in composite insulators, offering:
Strong adhesion and interface sealing
Thermal compatibility with core materials
Prevention of moisture ingress and interface tracking
This compatibility adds another layer of reliability in long-term UHV system operation.
For ultra-high voltage systems where precision, reliability, and longevity are non-negotiable, insulating silicone rubber is the ideal material for insulator design. It offers unmatched electrical insulation, environmental resistance, and mechanical strength in a lightweight and versatile package. Hefeng Silicone's expertise in producing advanced insulating silicone rubber compounds supports power utilities worldwide in their mission to operate safely, efficiently, and cost-effectively.
Whether you are developing new UHV transmission lines or upgrading aging infrastructure, our silicone rubber solutions are ready to meet your most stringent requirements.
Contact us today to learn more about how Hefeng Silicone can deliver tailor-made insulating silicone rubber materials for your next UHV application.
