17
Oct
Cable insulation selection and the difference between polyvinyl chloride, cross-linked polyethylene and ethylene-propylene rubber
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3.4.1 The selection of cable insulation type should comply with the following regulations:
1 Under the operating voltage, operating current and their characteristics and environmental conditions, the cable insulation characteristics should not be less than the conventional expected service life.
2 The selection should be based on factors such as operational reliability, ease of construction and maintenance, and the comprehensive economy of the maximum allowable operating temperature and cost.
3 It should comply with the requirements of fire prevention places and should be conducive to safety.
4. When it is clear that coordination with environmental protection is required, environmentally friendly cable insulation types should be selected.
3.4.2 The selection of insulation types for commonly used cables should comply with the following regulations:
1 The selection of insulation types for medium and low voltage cables should comply with the provisions of Articles 3.4.3 to 3.4.7 of this specification. Low voltage cables should use polyvinyl chloride or cross-linked polyethylene extruded insulation, and medium voltage cables should use cross-linked insulation. Polyethylene insulation type.
When it is clear that coordination with environmental protection is required, PVC insulated cables shall not be used.
2 For cable lines in high-voltage AC systems, cross-linked polyethylene insulation type should be used. In areas with more operating experience, self-contained oil-filled cables can be used.
3. For high-voltage DC transmission cables, non-drip impregnated paper insulation and self-contained oil-filled types can be selected. When it is necessary to increase the power transmission capacity, it is advisable to choose a type constructed of semi-synthetic paper materials.
It is not suitable to use ordinary cross-linked polyethylene cables in DC transmission systems.
3.4.3 For circuits such as mobile electrical equipment that are often bent or moved or have higher flexibility requirements, rubber insulated cables should be used.
3.4.4 In places where radiation is exposed, cables with resistance to radiation intensity such as cross-linked polyethylene or ethylene-propylene rubber insulation should be selected according to the requirements of the insulation type.
3.4.5 In places with high temperatures above 60℃, heat-resistant cables with heat-resistant polyvinyl chloride, cross-linked polyethylene or ethylene-propylene rubber insulation should be selected according to the requirements of high temperature withstand and duration and insulation type; in high-temperature environments above 100℃, Mineral insulated cables should be used.
Ordinary PVC insulated cables should not be used in high-temperature places.
3.4.6 In low temperature environments below minus 15°C, cross-linked polyethylene, polyethylene insulated, and cold-resistant rubber insulated cables should be selected according to low temperature conditions and insulation type requirements.
PVC insulated cables are not suitable for low temperature environments.
3.4.7 In densely populated public facilities and places with low-toxic flame retardant fire protection requirements, halogen-free insulated cables such as cross-linked polyethylene or ethylene-propylene rubber can be used.
When fire protection requires low toxicity, PVC cables should not be used.
3.4.8 Except for the circumstances specified in Articles 3.4.5 to 3.4.7 of this specification, polyvinyl chloride insulated cables can be used for circuits below 6kV.
3.4.9 For 6kV important circuits or cross-linked polyethylene cables above 6kV, the type characterized by three-layer co-extrusion process of inner and outer semi-conductive and insulating layers should be used.
The difference between polyethylene, polyvinyl chloride, cross-linked polyethylene and ethylene-propylene rubber
1. Polyethylene. The English abbreviation of PE is PE, which is a polymer of ethylene and is non-toxic. Easy to color, good chemical stability, cold resistance, radiation resistance, and good electrical insulation.
2. Polyvinyl chloride. The English abbreviation of PVC is a polymer of vinyl chloride. It has good chemical stability and is resistant to acid, alkali and some chemicals. It is moisture-resistant, aging-resistant and flame-retardant. The temperature when used cannot exceed 60°C (polyvinyl chloride will release toxic HCl smoke when burning), and it will harden at low temperatures. PVC is divided into soft plastic and hard plastic.
3. Cross-linked polyethylene. The English abbreviation of XLPE is an important technology to improve the performance of PE. The performance of cross-linked modified PE can be greatly improved, not only significantly improving the mechanical properties, environmental stress cracking resistance, chemical corrosion resistance, creep resistance and electrical properties of PE, but also The temperature resistance level is significantly improved, which can increase the heat resistance temperature of PE from 70°C to over 90°C, thus greatly broadening the application range of PE. At present, cross-linked polyethylene (XLPE) has been widely used in pipes, films, wire and cable materials, and foam products.
4. Ethylene-propylene rubber (EPR). The full name is cross-linked ethylene-propylene rubber. It has the stability of oxygen resistance, ozone resistance and partial discharge stability. It has a large dielectric loss factor, so it is only used in power cable lines with voltage levels lower than 138kV. Due to the good water resistance of ethylene-propylene rubber, ethylene-propylene rubber cables are suitable for submarine cables. And because ethylene-propylene rubber has good softness, it is more suitable for laying in mines and ships.
1 Under the operating voltage, operating current and their characteristics and environmental conditions, the cable insulation characteristics should not be less than the conventional expected service life.
2 The selection should be based on factors such as operational reliability, ease of construction and maintenance, and the comprehensive economy of the maximum allowable operating temperature and cost.
3 It should comply with the requirements of fire prevention places and should be conducive to safety.
4. When it is clear that coordination with environmental protection is required, environmentally friendly cable insulation types should be selected.
3.4.2 The selection of insulation types for commonly used cables should comply with the following regulations:
1 The selection of insulation types for medium and low voltage cables should comply with the provisions of Articles 3.4.3 to 3.4.7 of this specification. Low voltage cables should use polyvinyl chloride or cross-linked polyethylene extruded insulation, and medium voltage cables should use cross-linked insulation. Polyethylene insulation type.
When it is clear that coordination with environmental protection is required, PVC insulated cables shall not be used.
2 For cable lines in high-voltage AC systems, cross-linked polyethylene insulation type should be used. In areas with more operating experience, self-contained oil-filled cables can be used.
3. For high-voltage DC transmission cables, non-drip impregnated paper insulation and self-contained oil-filled types can be selected. When it is necessary to increase the power transmission capacity, it is advisable to choose a type constructed of semi-synthetic paper materials.
It is not suitable to use ordinary cross-linked polyethylene cables in DC transmission systems.
3.4.3 For circuits such as mobile electrical equipment that are often bent or moved or have higher flexibility requirements, rubber insulated cables should be used.
3.4.4 In places where radiation is exposed, cables with resistance to radiation intensity such as cross-linked polyethylene or ethylene-propylene rubber insulation should be selected according to the requirements of the insulation type.
3.4.5 In places with high temperatures above 60℃, heat-resistant cables with heat-resistant polyvinyl chloride, cross-linked polyethylene or ethylene-propylene rubber insulation should be selected according to the requirements of high temperature withstand and duration and insulation type; in high-temperature environments above 100℃, Mineral insulated cables should be used.
Ordinary PVC insulated cables should not be used in high-temperature places.
3.4.6 In low temperature environments below minus 15°C, cross-linked polyethylene, polyethylene insulated, and cold-resistant rubber insulated cables should be selected according to low temperature conditions and insulation type requirements.
PVC insulated cables are not suitable for low temperature environments.
3.4.7 In densely populated public facilities and places with low-toxic flame retardant fire protection requirements, halogen-free insulated cables such as cross-linked polyethylene or ethylene-propylene rubber can be used.
When fire protection requires low toxicity, PVC cables should not be used.
3.4.8 Except for the circumstances specified in Articles 3.4.5 to 3.4.7 of this specification, polyvinyl chloride insulated cables can be used for circuits below 6kV.
3.4.9 For 6kV important circuits or cross-linked polyethylene cables above 6kV, the type characterized by three-layer co-extrusion process of inner and outer semi-conductive and insulating layers should be used.
The difference between polyethylene, polyvinyl chloride, cross-linked polyethylene and ethylene-propylene rubber
1. Polyethylene. The English abbreviation of PE is PE, which is a polymer of ethylene and is non-toxic. Easy to color, good chemical stability, cold resistance, radiation resistance, and good electrical insulation.
2. Polyvinyl chloride. The English abbreviation of PVC is a polymer of vinyl chloride. It has good chemical stability and is resistant to acid, alkali and some chemicals. It is moisture-resistant, aging-resistant and flame-retardant. The temperature when used cannot exceed 60°C (polyvinyl chloride will release toxic HCl smoke when burning), and it will harden at low temperatures. PVC is divided into soft plastic and hard plastic.
3. Cross-linked polyethylene. The English abbreviation of XLPE is an important technology to improve the performance of PE. The performance of cross-linked modified PE can be greatly improved, not only significantly improving the mechanical properties, environmental stress cracking resistance, chemical corrosion resistance, creep resistance and electrical properties of PE, but also The temperature resistance level is significantly improved, which can increase the heat resistance temperature of PE from 70°C to over 90°C, thus greatly broadening the application range of PE. At present, cross-linked polyethylene (XLPE) has been widely used in pipes, films, wire and cable materials, and foam products.
4. Ethylene-propylene rubber (EPR). The full name is cross-linked ethylene-propylene rubber. It has the stability of oxygen resistance, ozone resistance and partial discharge stability. It has a large dielectric loss factor, so it is only used in power cable lines with voltage levels lower than 138kV. Due to the good water resistance of ethylene-propylene rubber, ethylene-propylene rubber cables are suitable for submarine cables. And because ethylene-propylene rubber has good softness, it is more suitable for laying in mines and ships.
