Do You Need To Bury The Solar Cables When Laying Its in Harsh Environments ?

The quality and performance of solar cables are critical to harvesting solar energy with higher efficiency in photovoltaic systems. Even a modest increase in cable resistance that results in increased losses is considered a larger energy loss and the cable will be rejected. The solar cable must withstand all the harsh environments such as UV radiation, rain, dust and dirt, temperature changes, humidity, insects and microorganisms, etc., because it has to work in the open atmosphere for a long time. Any frequent failures/replacements of solar cables will reduce overall project efficiency, so it is critical to evaluate solar cables prior to installation to ensure their successful performance over their expected lifespan by performing a series of tests.

Solar PV systems that are self-installed or installed on a roof have lower voltages, typically less than 100 volts. Grid-tied solar PV systems have higher voltage levels, and due to additional complexity and safety concerns, they are placed in a separate well-protected area and should only be operated by qualified personnel.

One of the most important factors to consider when choosing a solar cable size is the voltage drop between the PV array and the inverter. The total voltage drop between the PV array and the inverter is limited to 3%. To maintain this, in addition to cable size, the shortest length of solar cable is preferred.

The solar wires are designed to withstand temperatures ranging from -40°C to +90°C, making them adaptable to changing weather conditions. At a maximum ambient temperature of 90°C, the maximum conductor temperature is expected to be 120°C.

Solar cables may be single conductors with double insulation, usually routed through a suitable conduit/trough system, depending on their field of application. Use a single conductor with single wire armor for a more robust mechanical solution. Multi-core single wire armored cable is used for main DC cable between PV generator junction box and inverter.

Solar cables have a nominal DC voltage of 1.5 KV between conductors and a maximum of 1.8 kV between conductors and armor.

Solar cables should use flexible, heavy duty tinned copper conductors. Conductors require low-smoke, halogen-free cross-linked insulation and an outer jacket. Solar cables are usually black because they work in an open environment with ultraviolet radiation from the sun. Solar wires are not subject to normal bending or twisting forces after installation, so these two metrics are not particularly important. Insulation and jacketing must be able to withstand higher temperatures while still being mechanically stable, flame-retardant and halogen-free. In general, crosslinked polyolefin copolymers are preferred to meet these requirements. Type PVCA and EN: 50618 specifies special requirements for insulating/sheathing materials for solar cables compared to XLPE.

Solar power plants must operate in harsh weather environments, not only at high temperatures but also at low temperatures. Compared to PVC and XLPE materials, the aging temperature, heat setting temperature and cold bending temperature are all higher. A thermal endurance test is specified in the standard, which establishes that the temperature index should be >120 degrees Celsius and guarantees a predicted performance of 25 years.

Due to use in the open air, solar cables must prove their resistance to weathering and UV radiation.

To meet the efficiency requirements of solar photovoltaic systems, solar cables are available in various diameters and construction styles. The performance requirements for solar cables are defined by the international standard EN 50618. Solar cables must be evaluated before installation to verify that they will last for the necessary 25 years.