Cable Losses

Cable Losses refer to the energy loss that occurs when transmitting electric current through cables in a photovoltaic system. This loss is unavoidable, as every conductive material has some electrical resistance. When current flows through a conductor, part of the energy is converted into heat.

Causes of Cable Losses

  • Electrical Resistance: The specific resistance of the conductor material (e.g., copper or aluminum) determines how much the current flow is hindered.
  • Length of the Cable: The longer the cable, the greater the resistance and thus the losses.
  • Cross-Section of the Cable: A smaller cross-section leads to a higher resistance and thus greater losses.
  • Current Strength: A higher current increases the power loss.
  • Temperature: As the temperature rises, the resistance of the conductor increases, which raises the losses.

Effects of Cable Losses

  • Reduction of Yield: The energy lost due to cable losses is no longer available for its intended purpose, i.e., feeding into the grid or self-consumption.
  • Voltage Drop: Cable losses lead to a voltage drop along the line. If the voltage drops are too large, problems may occur in the operation of the system, e.g., reduced performance of the solar modules.
  • Heating of Cables: The heat generated by the losses can lead to overheating of the cables, which in the worst case poses a fire risk.

Minimizing Cable Losses

  • Selection of Suitable Cables:
    • Use of conductors with low specific resistance (e.g., copper).
    • Choosing an adequate cable cross-section that matches the expected current strength.
    • Considering the ambient temperature and possible temperature increases.
  • Optimization of Cable Routing:
    • Shortest possible cable lengths.
    • Avoiding loops and bends in the cables.
  • Regular Inspection:
    • Inspecting cables for damage.
    • Measuring the voltage drop.

Importance for System Design

The correct sizing of cables is an important factor for the economical operation of a photovoltaic system. Too small cable cross-sections lead to high losses and can affect the lifespan of the system. Therefore, careful planning and calculation of cable losses is essential.

Relevant Keywords: Photovoltaics, Solar System, Efficiency, System Design