EC Insulator Jiangxi Co., Ltd. is one of the most reliable manufacturers and suppliers of dc composite insulator in China. With abundant experience, we are committed to offering high quality custom service. Please feel free to wholesale premium dc composite insulator made in China here from our factory.
Product Overview
EC Insulator Jiangxi Co., Ltd. supplies high-performance DC composite insulators specially engineered for HVDC transmission and substation systems. Unlike conventional AC insulators, DC composite insulators are optimized to withstand continuous DC electrical stress, surface charge accumulation, and long-term polarised voltage operation. They provide stable electrical insulation and strong mechanical tension support for long-distance high-voltage DC overhead lines.
We have delivered this series for multiple domestic and overseas HVDC projects. One of our completed supply cases is ±800kV transmission line in a coastal heavy salt fog area, where we customized creepage distance and shed profile to meet pollution class IV requirements for this project. DC systems are far more sensitive to pollution, salt fog and ice conditions than AC systems, so we adopt upgraded silicone rubber formula and enhanced creepage designs to adapt to heavy polluted industrial zones, coastal salt-spray areas and cold ice-prone mountain regions.
Customers can provide project voltage grade, mechanical load requirement, site pollution class and altitude conditions, and our engineering team will offer fully customized DC insulator solutions.
Key Features
DC composite insulators adopt a three-part structure: high-strength ECR fiberglass epoxy core rod, DC-optimized HTV silicone rubber sheds, and hot-dip galvanized forged steel end fittings.
Different from AC environments, DC voltage causes continuous surface charge accumulation, which easily attracts dust and pollutants. Our upgraded DC special silicone rubber material delivers excellent anti-fouling, hydrophobic recovery and anti-aging performance, effectively suppressing leakage current and avoiding continuous surface discharge under long-term DC stress.
The overall weight is significantly lower than traditional porcelain DC insulators, greatly reducing tower load and simplifying high-altitude installation. All metal fittings undergo strict hot-dip galvanizing treatment to resist salt corrosion and atmospheric aging for long-term outdoor operation. The integral injection molding process eliminates internal gaps, preventing moisture penetration and internal partial discharge risks under permanent DC voltage.
Technical Specifications
|
Parameter |
Value |
|
Rated DC Voltage |
±400kV, ±500kV, ±600kV, ±800kV, ±1100kV |
|
Specified Mechanical Failing Load |
160kN – 1000kN |
|
Operating Temperature |
-40°C ~ +70°C |
|
Core Rod Material |
High-strength ECR fiberglass epoxy rod (DC anti-polarization design) |
|
Shed Material |
DC special grade HTV silicone rubber with enhanced hydrophobic migration |
|
Fitting Material |
Forged steel with full hot-dip galvanized finish |
|
Pollution Adaptability |
Customizable for pollution Class I, II, III, IV |
|
Partial Discharge |
≤5pC under standard test conditions |
|
Service Life |
25+ years under standard DC operating environments |
Notes: All test items are performed per IEC 62217, full test reports and certification documents will be provided upon shipment.
Application
DC composite insulators are exclusively applied in HVDC overhead transmission lines, converter station bus connections, DC tension strings and suspension string assemblies. They are the core insulation components for long-distance cross-provincial and cross-regional power transmission projects.
They are highly recommended for harsh DC operating scenarios, including coastal heavy salt fog areas, heavily industrial polluted regions, high-altitude cold zones and long-term humid environments. Based on our field experience, due to stricter DC electrical stress characteristics, standard AC composite insulators cannot replace DC dedicated models in HVDC projects.
Construction &Design
Our DC composite insulators adopt enhanced DC structural optimization. The ECR fiberglass epoxy core rod bears all tensile mechanical loads and is specially treated to resist long-term DC polarization aging. The silicone rubber housing is integrally injection-molded without any internal gaps, ensuring zero water infiltration and stable internal insulation performance.
End fittings are connected by hydraulic crimping technology instead of glue bonding, maintaining stable mechanical performance under long-term vibration and tension. The shed profile is redesigned for DC pollution accumulation characteristics, optimizing surface electric field distribution and effectively restraining DC corona and leakage current.
All structural dimensions strictly follow international HVDC insulator design standards, compatible with standard tower hardware and grading ring configurations for existing DC transmission projects.
Standards & Testing
Our DC composite insulators are manufactured and tested in accordance with mainstream HVDC insulator standards IEC 62217.
Each production batch undergoes professional DC-specific tests:
- DC power frequency withstand test
- Long-term DC partial discharge test
- Salt fog pollution aging test for DC conditions
- Hydrophobicity durability test
- Mechanical failing load test
- Galvanized layer thickness inspection
Complete factory test reports are provided for every shipment. Third-party witness testing is available upon tender requirements with adjusted production lead time.
Customization & Optional Accessories
We support full project-based customization for HVDC projects:
- Adjustable creepage distance for different pollution grades and altitudes
- Custom end fitting types: ball-and-socket, clevis and tongue
- Matched DC grading rings for ±500kV / ±800kV / ±1100kV models to optimize electric field
- Anti-bird sheds and anti-ice optimized shed profiles for special climate regions
- Custom mechanical tension levels and string lengths according to tower span design
Packaging & Delivery
All DC composite insulators are packed in ISPM 15 standard wooden crates. Each insulator is individually wrapped with PE film to prevent rubber surface scratching and metal fitting abrasion during long-distance sea freight.
Every product is permanently marked with DC voltage grade, mechanical load rating and batch number for full traceability. Bulk HVDC project orders take approximately 30–40 days after deposit. Small batch sample orders can be delivered within 10 working days.
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