Insulator strings are assemblies of disc-shaped insulators made from glass, porcelain, or polymer that provide electrical insulation and mechanical support in high-voltage transmission systems up to 765kV. They suspend or tension conductors at dead ends or sharp curves where substantial tensile loads occur.
The modular design allows customization to project-specific voltage levels (6kV to 765kV) and mechanical loads (40kN to 210kN). Available configurations include single and double tension strings for handling conductor tension, and single and double suspension strings for supporting conductors from towers. Components typically include disc insulators, suspension and tension clamps, anchor shackles, yoke plates, and clevis or ball-and-socket connections. Arcing rings may be integrated to manage flashover and corona effects.
Design features ensure compliance with IEC, ANSI, and DIN standards, incorporating minimum creepage distances of 25mm/kV to prevent leakage currents and corona-free hardware to minimize radio interference. All ferrous parts undergo hot-dip galvanization for corrosion resistance. The design accounts for environmental factors including altitude, pollution levels, and ice loading.
Manufacturing involves precision compression molding and automated production systems with quality control through standardized testing per IEC 61109, including type tests, sample tests, and routine verification of mechanical strength and electrical performance.
Enhance Grid Reliability with RaxPower Insulator String Supplier
As RaxPower, we pride ourselves on being China’s leading manufacturer of pole line hardware, specializing in insulator strings for the UK & Ireland markets. We connect stakeholders with manufacturers to deliver solutions that meet industry needs and provide whole life value through collaboration and feedback.
Utilities rely on products that will stand the test of time with as little maintenance as possible. With 21 years of manufacturing experience and 17,000 square meters of production workshops in Hebei Province, China, we have refined our insulator design using decades of engineering expertise. Our advanced processes like hot forging ensure parts with greater strength and accurate sizing, directly benefiting our insulator strings with enhanced durability and performance.
Our insulator strings feature:
- Stacked shed design to minimize material aging and electrical stresses, reducing long-term maintenance
- Excellent electrical insulation for high-voltage transmission without power leakage or flashover
- High mechanical strength to withstand wind, ice loading, and vibration in extreme conditions
- Durable materials and strict quality control for reliable, long-lasting service
Ideal for overhead transmission lines, substations, and various power systems, our products ensure safety and efficiency. Contact us today to learn more about our suspension insulator string products, and how we can help you meet your power transmission needs.
| Parameter | Specification | Unit |
|---|---|---|
| Insulator Type | Composite Long Rod (Typical) | – |
| Rated Voltage | 6 to 765 | kV |
| Maximum System Voltage | Up to 800 | kV |
| System Frequency | 50 / 60 | Hz |
| Lightning Impulse Withstand Voltage | 1050 (for 220 kV system) | kV peak |
| Power Frequency Withstand Voltage | 460 (for 220 kV system) | kV rms |
| Minimum Mechanical Failing Load | 40 to 210 | kN |
| Outside Diameter (Unit) | 100 | mm |
| Minimum Creepage Distance | 25 | mm/kV |
| Material | Glass, Porcelain, Polymer | – |
| Applicable Standards | IEC 61109, IEC 60305, ANSI, DIN | – |
Frequently Asked Questions（FAQS）
What is an insulator string and what is its primary function?
An insulator string is composed of disc-shaped insulators made from materials like glass, porcelain, or polymer, designed to provide electrical insulation and mechanical support in high-voltage transmission lines. It sustains substantial tensile loads from conductors at dead ends or sharp bends, ensuring proper insulation and mechanical integrity with voltage configurations adaptable up to 765kV.
What types and specifications are available?
We offer suspension and tension insulator strings in single or double configurations, made from porcelain, glass, or polymer. Insulation voltage levels range from 6kV to 220kV (customizable), mechanical failing loads from 40kN to 210kN, designed for extreme environments including high altitude, strong pollution, and heavy ice areas, with compliance to IEC and ANSI standards.
What quality certifications and test reports do you provide?
We provide type test reports and third-party certifications complying with IEC, IEEE, and national grid standards. Our insulators undergo routine, sample, and type tests—including electrical and mechanical evaluations—per IEC standards. Products pass rigorous multi-stage inspections and adhere to international standards like ISO 1461 for galvanization, ensuring extreme reliability for critical infrastructure.
Do you offer customization services?
Yes, we provide full OEM/ODM services including material selection for electrical environments, mechanical load-bearing optimization, corrosion-resistant surface treatments, interface compatibility analysis, insulation property improvements, and customized installation dimensions with hardware accessories. Our engineers offer free design support, working from samples or basic dimensions to develop precise technical drawings and cost-effective solutions tailored to your stress conditions, size range, and environmental factors.
What is the minimum order quantity and can I request samples?
Our minimum order quantity is 1 piece—we accept small orders with the same professionalism as large-scale projects. Yes, we provide free samples upon request to evaluate form, fit, function, quality, dimensional accuracy, and compatibility before committing to full production, reducing risk and ensuring satisfaction.
What is the typical lead time and product warranty?
Lead time depends on part complexity and order volume. Prototypes or low-volume runs are often delivered in 5–7 working days, with rush orders accommodated to meet critical project deadlines. We offer a 2-year warranty on all products to ensure reliability and customer satisfaction.
What should I do if the insulator string size does not match during installation?
Contact your account manager immediately. We will assist in confirming the cause and provide solutions such as modifying drawings, re-processing, or replacing parts to ensure smooth installation and minimize time and cost losses.
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