Cables are a critical part of solar power plants. They are responsible for linking various components and carrying the solar energy generated from modules through the inverter to the grid for transmission to load centres. Direct current (DC) cables that connect modules to combiner boxes to inverters may contribute to just 1 to 2 per cent of the total plant cost, but have a significant impact on the overall plant performance. Thus, their quality and proper sizing are vital to ensure optimised power output from a solar plant. Similarly, AC cables that transport solar power from inverters to the grid also need to be carefully sourced and sized.
Cables used for solar power projects have to be designed in such a manner that they can endure harsh conditions including high temperatures, ultraviolet (UV) radiation, atmospheric ozone and fire risks for the entire project life of 25 years. Further, adequate focus has to be given to make them capable of withstanding waterlogging and heavy rains without causing any untoward incidents. With solar photovoltaic (PV) projects involving kilometres of cables, it is critical to use quality products that do not harm the costly solar assets and human life. Thus, as with other equipment used in solar PV projects, many standards and specifications exist for solar cables. The various global standards used for ensuring the quality of solar cables include the European Standards, and those of the Underwriters Laboratory of USA, the International Electrotechnical Commission and TUV of Germany. The Bureau of Indian Standards has also developed certain cable standards that need to be followed in many solar tenders.
Many advancements are taking place in the solar cable space, which mainly focus on reducing voltage drops, increasing efficiency and decreasing costs. Thus, larger cross-section cables are used along with reduced cable lengths to minimise voltage drops. Further, higher voltages can help reduce energy loss, so another focus area is to increase operating voltage.
In a nutshell, as India moves ahead with its solar power goals, adequate focus should be given to the quality and safety of equipment such as cables and connectors. They might contribute to a small part of the overall cost, but are important factors in ensuring overall optimised solar generation.