A DC arc fault occurs when a loop is formed in the string, resulting in a current output that leads to an arc. This can happen due to various reasons, such as the inverter being operational while directly plugging and unplugging the string, short-circuits between the positive and negative poles of the strings, reversing the polarity of the connections, or having an imbalance in the number of series battery panels.
Solution: To address DC arc faults, follow these steps:
1. Before plugging and unplugging the string, ensure that the inverter has been turned off normally to avoid any arc faults during the process.
2. Check for any instances of positive and negative short-circuits within the string and ensure proper polarity of the connections before connecting to the inverter.
3. When connecting various strings with properly connected positive and negative poles, as well as strings with reversed connections, to the same MPPT input of the inverter, it is important to be aware of the potential for a short-circuit arc to occur. This can happen when positive and negative polarities are mixed, resulting in a short-circuit condition and the formation of an arc.
4. Make sure that you have an equal number of solar panels in each string when connecting them to the inverter. This will help ensure that there is no current flow between the strings that could cause arc faults when plugging or unplugging them. It's important to balance the strings properly to avoid any potential safety hazards.