In a solar photovoltaic power generation system, each link—from the solar panel to the inverter, and then to the grid or load—is crucial. The cables connecting these components have a significant impact on the overall performance of the system. Choosing the appropriate cable type is not only essential for the system’s safe and stable operation but also directly or indirectly affects the power generation efficiency of the photovoltaic system.
Importance of Cable Selection
- Current Carrying Capacity: The main function of a cable is to transmit current. If the selected PV cable has a cross-sectional area that is too small, it will produce greater resistance when carrying larger currents, leading to increased power losses, known as line losses. Line losses reduce the overall efficiency of the photovoltaic system and decrease power generation.
- Temperature Effect: When cables operate under high current, they generate heat. Excessive temperature not only accelerates cable aging but can also damage insulation materials, potentially leading to fires or other safety accidents. Choosing cables of appropriate specifications can effectively control temperature rise, ensuring the system operates safely and reliably.
- Voltage Drop: Long-distance transmission or using cables with too small a cross-section can lead to significant voltage drops, directly impacting the input voltage of the inverter and thus its operational efficiency. Reasonable cable selection can minimize voltage drops, ensuring the inverter operates at optimal efficiency and enhancing power generation.
Cable Selection Reference Table (from Combiner Box to Inverter)
| Number | Inverter | Copper cable specifications (from inverter to distribution box) | Aluminum cable specifications (from distribution box to grid connection point) | Grid connection distance | Note |
| 1 | SG10RT | ZC-YJV-0.6/1kV-5×4mm² | YJLV-0.6/1kV-3×10+1×6mm² | ≤100m | 1. AC cable distance from the mains connection box to the mains connection point ≤100m. 2. Copper and aluminum transition terminals should be crimped. 3. They should be crimped with a special crimping tool. 4. According to the actual conditions of the goods, aluminum core cable of the same diameter, aluminum alloy cable, single core aluminum cable and bundled aluminum cable can be used from the distribution box to the grid connection point. 5. The type of cable in the same area shall be consistent. |
| 2 | SG12RT | ZC-YJV-0.6/1kV-5×6mm² | YJLV-0.6/1kV-3×10+1×6mm² | ≤70m | |
| YJLV-0.6/1kV-3×16+1×10mm² | ≤100m | ||||
| 3 | SG15RT | ZC-YJV-0.6/1kV-5×10mm² | YJLV-0.6/1kV-3×16+1×10mm² | ≤100m | |
| 4 | SG20RT | ZC-YJV-0.6/1kV-5×10mm² | YJLV-0.6/1kV-3×16+1×10mm² | ≤70m | |
| YJLV-0.6/1kV-3×25+1×16mm² | ≤100m | ||||
| 5 | SG25RT | ZC-YJV-0.6/1kV-5×10mm² | YJLV-0.6/1kV-3×25+1×16mm² | ≤70m | |
| YJLV-0.6/1kV-3×35+1×16mm² | ≤100m | ||||
| 6 | SG33CX | ZC-YJV-0.6/1kV-3×16+2×10mm² | YJLV-0.6/1kV-3×25+1×16mm² | ≤70m | |
| YJLV-0.6/1kV-3×35+1×16mm² | ≤100m | ||||
| 7 | SG50CX | ZC-YJV-0.6/1kV-3×25+2×16mm² | YJLV-0.6/1kV-3×35+1×16mm² | ≤70m | |
| YJLV-0.6/1kV-3×50+1×25mm² | ≤100m | ||||
| 8 | SG10RT+SG10RT | Same as corresponding inverter cable model | YJLV-0.6/1kV-3×16+1×10mm² | ≤70m | |
| YJLV-0.6/1kV-3×25+1×16mm² | ≤100m | ||||
| 9 | SG12RT+SG12RT | Same as corresponding inverter cable model | YJLV-0.6/1kV-3×25+1×16mm² | ≤70m | |
| YJLV-0.6/1kV-3×35+1×16mm² | ≤100m | ||||
| 10 | SG15RT+SG12RT SG15RT+SG15RT SG20RT+SG12RT | Same as corresponding inverter cable model | YJLV-0.6/1kV-3×25+1×16mm² | ≤70m | |
| YJLV-0.6/1kV-3×35+1×16mm² | ≤100m | ||||
| 11 | SG20RT+SG15RT SG20RT+SG20RT | Same as corresponding inverter cable model | YJLV-0.6/1kV-3×35+1×16mm² | ≤70m | |
| YJLV-0.6/1kV-3×50+1×25mm² | ≤100m |
Cable Selection Reference Table (from Inverter to Photovoltaic Power Grid)
| Cable Selection Calculation from Combiner Box to Inverter | ||||
| Combiner Box Specifications | 16 inputs | 1 output | ||
| Maximum Output Current of Combiner Box Imax=Im*Number of Circuits | ||||
| Maximum Output Current of Combiner Box (ก) | Imax | 133.92 | ||
| Selected Cable Specification YJV22-0.6/1kV 2×50/2×70/2×95/2x120mm² | ||||
| Voltage Drop Requirement | ≤ | 1.50% | ||
| Allowed Voltage Drop ΔU=Vm*N*1.5% | ||||
| Voltage Drop (วี) | ΔU | 10.263 | ||
| Based on DC Voltage Drop Formula ΔU=ρ*I*2L/S, L=ΔU*S/2ρI | ||||
| YJV22-0.6/1kV 2 x 50 มม.² | Allowed Cable Length (m) | L | 107.6 | |
| YJV22-0.6/1kV 2 x 70 มม.² | Allowed Cable Length (m) | L | 150.7 | |
| YJV22-0.6/1kV 2 x 95 มม.² | Allowed Cable Length (m) | L | 204.5 | |
| YJV22-0.6/1kV 2 x 120 มม.² | Allowed Cable Length (m) | L | 258.3 | |
| YJV22-0.6/1kV 2 x 150 มม.² | Allowed Cable Length (m) | L | 322.9 | |
| YJV22-0.6/1kV 2 x 185 มม.² | Allowed Cable Length (m) | L | 398.2 | |
| YJV22-0.6/1kV 2 x 240 มม.² | Allowed Cable Length (m) | L | 516.6 | |
| YJV22-0.6/1kV 2 x 300 มม.² | Allowed Cable Length (m) | L | 645.8 | |
| YJV22-0.6/1kV 2 x 400 มม.² | Allowed Cable Length (m) | L | 861.1 | |