DC cable selection in solar power plants
Solar power plants generate DC (direct current) electricity, which is then converted into AC (alternating current) electricity using inverters. DC cables play an important role in transmitting the DC electricity from solar panels to inverters. Choosing the right DC cable is crucial for ensuring optimal performance and safety of the solar power plant.
Here are some considerations for selecting DC cables in solar power plants:
Rated Current: The rated current of the equipment connected by the cable should be considered while selecting the cable. The cable should be able to handle the maximum current without overheating or damage.
Voltage Drop: The voltage drop in the cable should be minimized to ensure optimal power transmission. The cable size should be selected to keep the voltage drop and losses to a minimum.
Short Circuit Withstand Capability: The cable should be able to withstand short circuits without getting damaged.
Cable Size: The size of the cable should be selected based on the requirements of the module/array interconnections, array to SCBs, and SCBs to inverter interconnections.
Conductor Resistance: Copper conductors are preferred for their low resistance, which results in lower energy losses and improved system efficiency.
Energy Loss: The average DC cable energy loss under STC (standard test conditions) should not exceed 1.5%.
Here are some cable specifications that can be considered for solar power plants:
1Cx400 Sqmm XLPE AL.ARM. Cable: This cable can be used for the SCB (string combiner box) to inverter interconnection. It has a copper conductor and XLPE insulation, which provides good resistance to heat, moisture, and UV radiation. The AL.ARM. (aluminum armored) sheath provides mechanical protection and resistance to rodents.
1Cx6Sqmm UV Protected Copper Cable: This cable can be used for the string to SCB interconnection. It has a copper conductor and UV protected insulation, which provides good resistance to UV radiation and moisture.
Some standards and certifications that can be considered while selecting DC cables for solar power plants include IEC 60228 (class 2), UL 4703, IEC 60332-1, IEC 61034, IEC 60287, IEC 60216, EN 50618, IEC 60754-1, TUV 2 pfg 1169 02.2007 PV1-F, and IEC 60811.
In conclusion, selecting the right DC cable is crucial for ensuring optimal performance, safety, and reliability of solar power plants. Factors like rated current, voltage drop, short circuit withstand capability, cable size, conductor resistance, and energy loss should be considered while selecting the cable. Standard and certifications can also be considered for quality assurance.