Analysis of Cable Selection Factors in Photovoltaic System
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September 21 11:11:53, 2025
This paper primarily focuses on the selection and design of cables used in photovoltaic (PV) systems. It covers essential factors to consider when choosing cables, how to select appropriate cables for different environmental conditions, and the key principles that govern cable size specifications. Proper cable selection is crucial for ensuring system efficiency, safety, and longevity.
When selecting cables for a PV system, several critical factors must be taken into account. First, the insulation performance of the cable is vital to prevent electrical leakage and ensure safe operation. Second, heat-resistant and flame-retardant properties are necessary, especially in high-temperature environments. Third, cables should be resistant to moisture and UV exposure to avoid degradation over time. Fourth, the method of cable installation—whether overhead, underground, or in conduits—must be considered to protect against mechanical damage. Fifth, the type of conductor material, such as copper or aluminum, influences both cost and performance. Lastly, the cable’s cross-sectional size must be chosen carefully based on current load and voltage drop considerations.
Different components within a PV system require distinct types of cables due to varying environmental conditions and functional requirements. For example, connections between solar modules must undergo UL testing, with cables rated for 90°C heat resistance, anti-acid and chemical resistance, moisture protection, and UV resistance. Cables connecting batteries to inverters can be multi-strand wires or electric welder cables that meet UL standards. Connections between PV arrays can be either above ground or buried, requiring protection from moisture and sunlight, often using heat-resistant conduits rated at 90°C. Indoor wiring in dry environments typically uses shorter DC connections for simplicity and efficiency.
In terms of cable sizing, there are specific guidelines to follow. For short-distance DC connections from the battery to indoor equipment, the selected cable’s rated current should be 1.25 times the continuous current. When connecting within a PV array, the rated current should be 1.56 times the maximum continuous current. For AC loads and inverter connections, the rated current should also be 1.25 times the calculated maximum continuous current. Additionally, temperature effects must be considered, as they can significantly impact cable performance. Voltage drop should not exceed 2% to maintain system efficiency. Finally, the appropriate cable diameter is determined by two main factors: the current it will carry and the voltage loss in the circuit. The formula for calculating line loss is:
**Line Loss = Current × Circuit Length × Cable Voltage Factor (obtained from the manufacturer).**
By following these guidelines, engineers and installers can ensure reliable and efficient cable performance in photovoltaic systems.