In the field of modern energy, with the popularization and development of solar power generation technology, the frequency of use of photovoltaic cables and ordinary cables has also increased. Many people may be confused about the difference between photovoltaic cables and ordinary cables, especially when installing solar photovoltaic systems. This article will explore the difference between photovoltaic cables and ordinary cables in detail, analyze the characteristics and applications of photovoltaic cables, and provide some purchase suggestions.
1. Definition of photovoltaic cable
Photovoltaic cable, as the name suggests, is a cable designed specifically for solar photovoltaic power generation systems. It is mainly used for power transmission between solar panels and inverters, and between inverters and power grids or energy storage devices. The design and material of photovoltaic cables ensure that they can withstand long-term exposure to harsh conditions in outdoor environments, such as ultraviolet radiation, high temperature, low temperature, moisture, chemical corrosion, etc.
Photovoltaic cables are usually composed of three parts: conductor, insulation layer and outer sheath. Its conductor material is often copper or aluminum, and the insulation layer and sheath are made of weather-resistant and UV-resistant materials to ensure that the cable can operate stably in the sun, high temperature, wind and rain.
2. Definition of ordinary cables
Ordinary cables refer to cables widely used in various power transmission and power control systems. These cables are not designed specifically for the solar industry. Ordinary cables can be used in a variety of environments such as indoors, outdoors, and underground, but their weather resistance, UV resistance, and corrosion resistance are usually weak and cannot meet the long-term and stable needs of solar power generation systems.
Ordinary cables are widely used in places such as building electrical, industrial power transmission, and household electrical systems. Usually, the sheath materials of these cables do not have sufficient UV resistance or high temperature resistance, so they are not suitable for long-term use in direct sunlight or extreme environments.
3. The main differences between photovoltaic cables and ordinary cables
3.1 Materials and weather resistance
The insulation layer and outer sheath of photovoltaic cables are usually made of special materials, such as cross-linked polyethylene (XLPE) and polyvinyl chloride (PVC), which have excellent high temperature resistance, UV resistance, moisture resistance, and corrosion resistance. Since photovoltaic cables usually need to be installed outdoors and are exposed to sunlight for a long time, photovoltaic cables must be able to withstand strong ultraviolet radiation, temperature changes, and rain erosion. In order to ensure long-term stable operation, the outer sheath of photovoltaic cables is usually weather-resistant and can resist high temperature, low temperature, acid and alkali corrosion and other environmental factors.
In contrast, the outer sheath of ordinary cables is mostly made of conventional materials such as PVC. Although these materials are suitable for power transmission in indoor or mild environments, they are prone to aging, cracking or corrosion when exposed to harsh outdoor environments such as sunlight and rain for a long time, so they are not suitable for use in solar energy systems.
3.2 Conductors and electrical properties
The conductors of photovoltaic cables are usually made of high-purity copper or aluminum to ensure efficient transmission of electrical energy and low resistance. Copper conductors have lower resistance, so they can reduce energy loss during transmission, thereby improving the overall efficiency of the system. Aluminum conductors are relatively light and low in cost, so they are also used in some low-cost systems.
The conductor materials of ordinary cables are also mostly copper or aluminum, but their electrical performance is usually not as good as that of photovoltaic cables. The electrical transmission design of ordinary cables is not specifically optimized to adapt to the high voltage and high current conditions in solar energy systems, so they are relatively low in efficiency.
3.3 Voltage level and scope of application
Photovoltaic cables are usually designed for high-voltage photovoltaic systems, especially the DC voltage output by photovoltaic panels generally ranges from 200V to 1000V, or even higher. In order to cope with high voltage, photovoltaic cables have high electrical insulation performance and can withstand strong voltage pressure.
The voltage level of ordinary cables varies according to different uses, but in general, their voltage level is not as high as that of photovoltaic cables, and they are usually used in low-voltage or medium-voltage power transmission systems.
3.4 Safety and fire resistance
The safety performance requirements of photovoltaic cables are very high, especially in the case of short circuits and overloads that may occur during power transmission. Photovoltaic cables need to have sufficient anti-interference ability and fire resistance. In order to meet these safety requirements, the sheath of photovoltaic cables usually adds flame retardant and fire resistant functional designs to ensure that no fire or electrical accidents will occur in the event of a fault.
Although ordinary cables also have certain safety performance, they usually do not have the high fire resistance of photovoltaic cables. In some high-risk places or special environments, ordinary cables may not meet the requirements.
3.5 Long-term stability and lifespan
The design life of photovoltaic cables is usually more than 25 years, which matches the service life of solar power generation systems. During long-term use, photovoltaic cables need to have excellent aging resistance and be able to maintain stable electrical performance and structural integrity under long-term exposure to environmental conditions such as ultraviolet rays, temperature fluctuations and moisture.
The service life of ordinary cables is relatively short, especially in outdoor environments. Ordinary cables may experience aging, cracking and other problems within a few years, affecting the stability and safety of power transmission.
4. Common specifications and selection of photovoltaic cables
Photovoltaic cables usually have a variety of specifications, suitable for photovoltaic power generation systems of different sizes and types. The following are some common photovoltaic cable specifications:
Voltage level: The voltage level of photovoltaic cables is usually 600V to 1500V, which is suitable for photovoltaic systems of different power levels.
Current carrying capacity: The current carrying capacity of photovoltaic cables varies depending on the cross-sectional area of the cable and the conductor material. Common cable sizes include 1.5mm², 2.5mm², 4mm², 6mm², etc.
Weather resistance: The outer sheath of photovoltaic cables has good weather resistance and can maintain stable performance under long-term exposure to ultraviolet rays and other harsh environments.
Applicable temperature range: The operating temperature range of photovoltaic cables is generally -40℃ to +90℃, ensuring normal operation under extreme temperature conditions.
When selecting photovoltaic cables, in addition to voltage and current specifications, factors such as the installation environment (such as whether it is outdoors, whether there is high humidity, etc.) and the durability of the cable should also be considered. Photovoltaic cables must meet relevant international and industry standards, such as IEC 60216, IEC 60332, etc.