SPD (Surge Protective Device)

The solar panels of photovoltaic systems occupy a space proportional to the power that can be obtained. When the occupied area becomes significant, the systems are more subject to the effects of lightning strikes, especially indirect ones. Installing surge arresters for each polarity closest to the strings would be a good idea to avoid breakups. The choice of the voltage of the SPD (Surge Protection Device) on the DC side systems, which are isolated from the ground, can be calculated using the following formula:

VC (SPD) = VOC STC * K

• VC (SPD) = Maximum continuous voltage of the SPDs in DC
• VOC STC (string) = Voltage open circuit of the string = VOC STC (Module) * N
• VOC STC (Module) = Voltage open circuit of the photovoltaic module
• K= 1,20
• N = Number of modules in series for each string

Figure 1 - Difference between STC String and Module

After calculating the VC (SPD), the SPD is chosen from among the models having the VC voltage of the SPDs with a value higher than that has been calculated.

Figure 2 - Example of SPD protection

Island photovoltaic

 Figure 3 - Island photovoltaic

Photovoltaic connected to the national network.

  Figure 4 - Photovoltaic connected to the national network

 conclusion

As you can see from the photos above, SPD arresters are of fundamental importance for a photovoltaic system. The choice of its capacity is significant for the protection of the system. Unfortunately, this is sometimes completely forgotten.

The choice of panels is critical, poor quality panels can ruinously compromise the whole system as per Figure 7. Another serious problem to keep under control is cleaning under the panels, including all external phenomena such as bird nests, as shown in figure 8. All this can cause quite serious fires

Excellent SPD arresters are built ABB. It is possible to buy On the website directly here.