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Introduction to various types of cables: DC high-voltage cables
2026-06-21
(Disclaimer: Some of the information in this article is sourced from the internet. Please carefully identify and use it.)
DC high-voltage cable is a special cable designed for transmitting high-voltage direct current, mainly used in fields such as electrostatic spray painting, high-voltage direct current transmission (HVDC) power equipment testing, etc. Its core feature is high voltage resistance, low leakage current, and adaptability to polarity reversal. The structural design needs to solve technical problems unique to DC electric fields such as space charge accumulation. Here is a detailed analysis:
1. Definition and Core Features
DC high-voltage cables are used to transmit DC voltage (usually ≥ 1kV), and their insulation materials and structures need to be optimized for the DC electric field. Compared with AC cables, space charge effects and polarity reversal tolerance need to be additionally considered.
Voltage level: covering ± 5kV to ± 500kV and above (such as GYVZ-150 type with a withstand voltage of 200kV).
Typical applications: Static spray painting equipment, HVDC transmission, high-voltage generator testing, etc.
2. Key characteristics High voltage stability: The insulation layer needs to suppress the accumulation of space charges and prevent electric field distortion from causing breakdown.
Material adaptability: Cross linked polyethylene (XLPE) is the mainstream insulation material, and silicone rubber is used in flexible demand scenarios.
Environmental tolerance: Wide working temperature range (such as silicone rubber cables -45 ℃~180 ℃).
2. Requirements and structural characteristics
| Usage characteristics | Structural characteristics |
|---|---|
| 1. DC high-voltage cables have a wide range of applications and are mainly used in various new technology equipment in industries, such as X-ray machines, electron beam processing, electron bombardment furnaces, electron guns, electrostatic painting, etc. These products generally have high power supply, so the filament current passing through the cable is also relatively large, up to tens of amperes; The voltage ranges from 10KV to 200KV; 2. Most cables are fixedly laid and generally do not come into direct contact with humans; 3. The energy transmitted by cables is relatively high, and the thermal properties of the cables should be considered. The allowable working temperature of the cables should be taken into account; 4. Some devices use medium frequency short-term discharge, cables It needs to withstand 2.5-4 times the voltage, so sufficient electrical strength should be considered; 5. Due to the lack of standardization and serialization of various devices, the working voltage between the filaments and between the filament core and the grid core of the same type of equipment are different, so they need to be selected separately. | 1. Conductive wire core: The wire core is generally 3 cores, but there are also 4 or 5 cores; 2. Generally, 3-core cables have two filament heating cores and one control core; The wire and shield are subjected to high DC voltage; 3. There are two forms of 3-core cables: one is similar to X cable, which uses phase separated insulation and then uniformly wraps a semiconducting layer and a high-voltage layer; Another method is to use the control core as the central conductor, extrude insulation, and then twist the two filaments in a concentric manner, followed by extruding a semiconducting layer and a high-voltage insulation layer; High voltage insulation layer: Generally, the maximum DC field strength of natural styrene butadiene rubber is 27KV/mm, and that of ethylene propylene insulation is 35KV/mm; 4. Outer shielding layer: woven with 0.15-0.20mm tin plated copper wire, with a weaving density of not less than 65%; Or use metal tape wrapping; 5. Sheath, extruded with special soft polyvinyl chloride or nitrile polyvinyl chloride. |
3. Technical Challenges and Solutions
Problem: Charge accumulation under DC electric field leads to local electric field enhancement, accelerating insulation aging.
Solution: Ultra pure XLPE (Nordic Chemical Technology); Nanoparticle doping (such as magnesium oxide) regulates trap energy levels.
2. Polarity reversal tolerance Problem: The VSC-HVDC system needs to withstand voltage polarity reversal (such as wind power grid connection).
Test standard: CIGRE 419 requires passing the superimposed impulse voltage test (e.g. ± 150kV cable needs to withstand 277.5kV reversal).
3. Degassing of by-products XLPE cross-linking byproducts (such as methane) need to be degassed to avoid dissociation and exacerbation of charge accumulation during operation.
4. Application scenarios
Industrial equipment: Electrostatic spray painting (GYVZ-50) aluminum-plastic separator.
Energy transmission: HVDC submarine cables (such as ± 400kV XLPE cables).
Power test: Testing lightning arrester cables for DC high-voltage generators (such as 50kV silicone rubber wires).
5. Standards and Selection
International standard: IEC 60245 (rubber insulation) CIGRE 419 (HVDC testing).
Selection points:
- Voltage level (such as selecting silicone rubber wire for ± 50kV and XLPE cable for ± 320kV).
- Environmental requirements (YCW type for oil resistance and Litz wire structure for high frequency).
6. Summary DC high-voltage cables are key components of DC power systems, and their technical core lies in insulation material optimization and space charge control. With the development of HVDC transmission and new energy, high-voltage grade (such as ± 640kV) thermoplastic insulated (such as PP) cables will become a key focus in the future.
※If you need to purchase Cable Materials, you can choose Wuxi Henglong Cable Material Co., Ltd., a well-known manufacturer in the Chinese cable materials industry.
