fix
fix

Analysis of the Advantages and Disadvantages of Solar PV Wire Insulation Materials

  • news2023-10-12
  • news

        The performance of insulating materials directly affects the quality, processing efficiency, and application scope of solar photovoltaic cables. This article will briefly analyze the advantages and disadvantages of commonly used solar photovoltaic cable insulation materials, aiming to discuss with the industry and gradually shorten the gap with international cables.

        Due to the differences between different insulating materials, the production of wires and cables and wire processing have their own characteristics. A full understanding of these characteristics will be beneficial to the selection of photovoltaic cable materials and the control of product quality.

 

1. PVC polyvinyl chloride cable insulation material

        PVC polyvinyl chloride (hereinafter referred to as PVC) insulation material is a mixture of stabilizers, plasticizers, flame retardants, lubricants and other additives added to PVC powder. According to the different application and different characteristics of the wire and cable, the formula is adjusted accordingly. After decades of production and use, the current PVC manufacturing and processing technology has become very mature. PVC insulation material has a very wide range of applications in the field of solar photovoltaic cables, and has obvious characteristics of its own:

        1) The manufacturing technology is mature and easy to form and process. Compared with other types of cable insulation materials, it not only has low cost, but also can be effectively controlled in terms of surface color difference, light dumb degree, printing, processing efficiency, soft hardness, conductor adhesion, mechanical, physical and electrical properties of the wire itself.

        2) It has very good flame-retardant properties, so PVC insulated cables can easily reach the flame-retardant grades required by various standards.

        3) In terms of temperature resistance, through the optimization and improvement of the material formula, the currently commonly used PVC insulation types mainly include the following three categories:

 

Material category Rated temperature (maximum) Application Use characteristics
normal type 105℃ Insulation and jacket Different hardness can be used according to requirements, generally soft, easy to shape and process.
Semi-rigid (SR-PVC) 105℃ Core insulation The hardness is higher than the ordinary type, and the hardness is above Shore 90A. Compared with the ordinary type, the insulation mechanical strength is improved, and the thermal stability is better. The disadvantage is that the softness is not good, and the scope of use is affected.
Cross-linked PVC (XLPVC) 105℃ Core insulation Generally, it is cross-linked by irradiation to transform ordinary thermoplastic PVC into insoluble thermosetting plastic. The molecular structure is more stable, the mechanical strength of insulation is improved, and the short-circuit temperature can reach 250°C.

 

        4) In terms of rated voltage, it is generally used for rated voltages of 1000V AC and below, which can be widely used in household appliances, instrumentation, lighting, network communications and other industries.

 

PVC also has some shortcomings that limit its use:

        1) Because it contains a large amount of chlorine, a large amount of dense smoke will suffocate when burning, affect visibility, and produce some carcinogens and HCl gas, which will cause serious harm to the environment. With the development of low-smoke halogen-free insulation material manufacturing technology, gradually replacing PVC insulation has become an inevitable trend in cable development. At present, some influential and socially responsible enterprises have clearly put forward the timetable for replacing PVC materials in the company’s technical standards.

        2) Ordinary PVC insulation has poor resistance to acids and alkalis, heat-resistant oils, and organic solvents. According to similar chemical principles of compatibility, PVC wires are easily damaged and cracked in the specified environment. However, with its excellent processing performance and low cost. PVC cables are still widely used in household appliances, lighting, mechanical equipment, instrumentation, network communications, building wiring and other fields.

 

2. XLPE cable insulation material

        Cross-linked polyethylene (Cross-linke PE, hereinafter referred to as XLPE) is a polyethylene that is subjected to high-energy rays or cross-linking agents, and can transform from a linear molecular structure to a three-dimensional structure under certain conditions. At the same time, it is transformed from thermoplastic into insoluble thermosetting plastic. After being irradiated, XLPE solar cable insulation sheath has the properties of high temperature resistance, ultraviolet radiation resistance, oil resistance, cold resistance, etc., with a service life of more than 25 years, which is incomparable with ordinary cables.

        At present, there are three main cross-linking methods in the application of wire and cable insulation:

        1) Peroxide crosslinking. Firstly, polyethylene resin is mixed with appropriate cross-linking agent and antioxidant, and other ingredients are added as needed to make cross-linkable polyethylene mixture particles. During the extrusion process, cross-linking occurs through the hot steam cross-linking pipe.

        2) Silane crosslinking (warm water crosslinking). It is also a chemical cross-linking method. The main mechanism is to cross-link organosiloxane and polyethylene under specific conditions. The degree of cross-linking can generally reach about 60%.

        3) Irradiation crosslinking is the use of high-energy rays such as r-rays, α-rays, electron rays and other energies to activate the carbon atoms in polyethylene macromolecules for cross-linking. The high-energy rays commonly used in wires and cables are electron rays produced by electron accelerators. , Because the cross-linking relies on physical energy, it is a physical cross-linking. The above three different cross-linking methods have different characteristics and applications:

 

Cross-linking category Features Application
Peroxide crosslinking During the cross-linking process, the temperature must be strictly controlled, and cross-linking is generated through the hot steam cross-linking pipeline. It is suitable for the production of high-voltage, large-length, large-section cables, and the production of small specifications is more wasteful.
Silane crosslinking Silane cross-linking can use general equipment. Extrusion is not limited by temperature. Cross-linking starts when exposed to moisture. The higher the temperature, the faster the cross-linking speed. It is suitable for cables with small size, small specification and low voltage. The cross-linking reaction can only be completed in the presence of water or moisture, which is suitable for the production of low-voltage cables.
Radiation crosslinking Due to the energy of the radiation source, it is used for insulation that is not too thick. When the insulation is too thick, uneven irradiation is likely to occur. It is suitable for the insulation thickness is not too thick, high temperature resistant flame retardant cable.

 

Compared with thermoplastic polyethylene, XLPE insulation has the following advantages:

        1) Improved heat deformation resistance, improved mechanical properties at high temperatures, and improved resistance to environmental stress cracking and heat aging.

        2) Enhanced chemical stability and solvent resistance, reduced cold flow, basically maintained the original electrical performance, long-term working temperature can reach 125 ℃ and 150 ℃, cross-linked polyethylene insulated wire and cable, also improved The short-circuit withstand ability, its short-term temperature can reach 250 ℃, the same thickness of wire and cable, the current carrying capacity of XLPE is much larger.

        3) XLPE insulated wires and cables have excellent mechanical, waterproof and radiation resistance properties, so they have a wide range of applications. Such as: electrical internal connection wires, motor leads, lighting leads, automotive low-voltage signal control wires, locomotive wires, subway wires and cables, mining environmental protection cables, marine cables, nuclear power laying cables, TV high-voltage cables, X-RAY firing high-voltage cables, and power Transmission wire and cable industries.

 

XLPE solar cable

Slocable XLPE Solar Cable

 

XLPE insulated wires and cables have significant advantages, but they also have some shortcomings of their own, which limit their use:

1) Poor heat-resistant blocking performance. Processing and using wires at a temperature exceeding the rated temperature of the wires can easily cause adhesion between the wires, which can seriously cause the insulation to break and form a short circuit.

2) Poor heat-resistant cut-through performance. At temperatures exceeding 200°C, the wire insulation becomes extremely soft, and squeezed and impacted by external forces can easily cause the wire to cut through and short-circuit.

3) The color difference between batches is difficult to control. During the processing, it is easy to scratch, whitish, and print off.

4) XLPE insulation at 150°C temperature resistance level, completely halogen-free and able to pass the VW-1 combustion test of UL1581 specification, and maintain excellent mechanical and electrical performance, there are still certain bottlenecks in manufacturing technology, and the cost is high.

5) There is no relevant national standard for the insulated wire of this kind of material in the connection of electronic and electrical appliances.

 

3. Silicone rubber cable insulation material

        Silicone rubber is also a polymer molecule is a chain structure formed by SI-O (silicon-oxygen) bonds. The SI-O bond is 443.5KJ/MOL, which is much higher than the C-C bond energy (355KJ/MOL). Most of the silicone rubber wires and cables use cold extrusion and high temperature vulcanization processes. Among many synthetic rubber wires and cables, due to its unique molecular structure, silicone rubber has better performance than other ordinary rubbers:

        1) Very soft, good elasticity, odorless and non-toxic, not afraid of high temperature and resistant to severe cold. The operating temperature range is -90~300℃. Silicone rubber has much better heat resistance than ordinary rubber, and it can be used continuously at 200°C or for a period of time at 350°C. Silicone rubber cables have good physical and mechanical functions and chemical stability.

        2) Excellent weather resistance. Under ultraviolet light and other climatic conditions for a long time, its physical properties have only slight changes.

        3) Silicone rubber has a high resistivity, and its resistance remains stable in a wide range of temperature and frequency.

 

weather resistant rubber flex cable

Slocable Weather Resistant Rubber Flex Cable

 

        At the same time, silicone rubber has good resistance to high-voltage corona discharge and arc discharge. Silicone rubber insulated cables have the above-mentioned series of advantages, especially in TV high-voltage device cables, microwave oven high-temperature resistant cables, induction cooker cables, coffee pot cables, lamp leads, UV equipment, halogen lamps, oven and fan internal connection cables, etc. It is the field of small household appliances that has a wide range of applications, but some of its own shortcomings also limit the wider application. such as:

        1) Poor tear resistance. Extruded by external force during processing or use, it is easy to be damaged by scraping and causing short circuit. The current protective measure is to add a glass fiber or high-temperature polyester fiber woven layer to the silicone insulation, but it is still necessary to avoid damage caused by external force extrusion as much as possible during the processing.

        2) The vulcanizing agent added for vulcanization molding currently mainly uses double 24. The vulcanizing agent contains chlorine, and completely halogen-free vulcanizing agents (such as platinum vulcanization) have strict requirements on the production environment temperature and are expensive. Therefore, attention should be paid to the processing of the wire harness: the pressure of the pressure roller should not be too high, and it is best to use rubber material to prevent poor pressure resistance caused by fracturing during the production process. At the same time, please note: necessary protective measures should be taken during the production of glass fiber yarn to prevent inhalation into the lungs and affect the health of employees.

 

4. Cross-linked ethylene propylene rubber (XLEPDM) cable insulation material

        Cross-linked ethylene propylene rubber is a terpolymer of ethylene, propylene and non-conjugated diene, which is cross-linked by chemical or irradiation. The advantages of cross-linked EPDM rubber insulated wires, integrated polyolefin insulated wires and ordinary rubber insulated wires:

        1) Soft, flexible, elastic, non-adhesive at high temperature, long-term aging resistance, resistance to harsh weather (-60~125℃).

        2) Ozone resistance, UV resistance, electrical insulation resistance, and chemical resistance.

        3) Oil resistance and solvent resistance are comparable to general-purpose chloroprene rubber insulation. The processing is carried out by ordinary hot-extrusion processing equipment, and irradiation cross-linking is adopted, which is simple and low-cost. Cross-linked EPDM rubber insulated wires have many of the above advantages, and are used in refrigeration compressor leads, waterproof motor leads, transformer leads, mine mobile cables, drilling, automobiles, medical equipment, boats, and general electrical internal wiring.

 

The main disadvantages of XLEPDM wire are:

1) Compared with XLPE and PVC wires, the tear resistance is poor.

2) Adhesion and self-adhesiveness are poor, which affects subsequent processability.

Dongguan Slocable Photovoltaic Technology Co.,LTD.

Add:Guangda Manufacturing Hongmei Science and Technology Park, No. 9-2, Hongmei Section, Wangsha Road, Hongmei Town, Dongguan, Guangdong, China

TEL:0769-22010201

E-mail:pv@slocable.com.cn

facebook pinterest youtube linkedin Twitter ins
CE RoHS ISO 9001 TUV
© Copyright © 2022 Dongguan Slocable Photovoltaic Technology Co.,LTD.Featured Products - Sitemap 粤ICP备12057175号-1
mc4 extension cable assembly, solar cable assembly, pv cable assembly, mc4 solar branch cable assembly, solar cable assembly mc4, cable assembly for solar panels,
Technical Support:Soww.com