The Design Selection and Cost Optimization of DC Cables in the Photovoltaic Industry

In recent years, the technological development of the photovoltaic industry has been accelerating at an increasingly rapid pace. The power of a single module is constantly increasing, and the current of the string is also getting larger. The current of high-power modules has exceeded 17A. In the aspect of system design, the use of high-power modules and reasonable over-configuration can reduce the initial investment cost and the cost per kilowatt-hour of the system. Considering that the cost of AC and DC cables accounts for a certain proportion in the entire system, then exactly how should we conduct design selection to reduce costs?

DC cables are usually installed outdoors. It is generally recommended to select photovoltaic-specific cables that have undergone irradiation cross-linking. After being irradiated by high-energy electron beams, the molecular structure of the insulation layer material of these cables changes from linear to three-dimensional reticular. The temperature resistance grade is raised from 70°C in the non-cross-linked state to 90°C, 105°C, 125°C, 135°C, or even 150°C. Compared with cables of the same specification, the current-carrying capacity is increased by 15 - 50%, and it can withstand severe temperature changes and chemical erosion, and can be used outdoors for more than 25 years. When selecting DC cables, it is necessary to choose products from regular manufacturers with relevant certifications to meet the requirements of long-term outdoor use.

Currently, the PV1-F 1*4 4-square cable is more widely used in the photovoltaic field. However, as the current of photovoltaic modules increases and the power of single inverter increases, the length of DC cables is also gradually increasing, and the application of 6-square DC cables is also increasing.