Types of Lightning Strike Risks
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Direct strike
The lightning current flows through the PV array, the connected system components and the building services equipment, which generally is destroyed. Severe mechanical damage can also not be ruled out.
Indirect strike
A strike occurs close to the generator or the distribution room. Parts of the lightning current can flow across the PV array and/or enter the cabling. The voltage is boosted in the system cables.
Close strike
Within a radius of approximately 500 m of the lightning discharge channel, magnetic (inductive) effects influence cable loops of all kinds. With each discharge, large overvoltages develop in the loops, which can lead to errors or destruction.
Distant strike
At greater distances to the system, capacitive effects occur. This means that an electric field is created between cloud or lightning channel (high potential) and electrically conductive parts of the plant, which is separated by an induced charge and therefore creates voltage within the system. Upon a sudden collapse of the field by the strike, the charges equalize through a surge current. If a surge current flows through the line, the current and the characteristic impedance cause a surge voltage in the line.
Two protection goals must be met:
- Protection from the effects of direct lightning strikes in the system components themselves or the system buildings.
- Protection from lightning overvoltages which can also be caused by indirect lightning strikes.
According to VDE 0185 Part 1, two protective measures are available: the installation of an external lightning protection system (insulated or not insulated, i.e. with or without lightning currents across system components) and the installation of an internal lightning protection system (overvoltage protection measures).
All work on the inverter and the cabling of the PV array must be carried out by an electrically qualified person. SMA accepts no liability for the information and solutions given in the Online Service Center. Additional information can be found in our Online Service Center’s terms and conditions of use.