The voltage of a lightning impulse, also known as lightning surge voltage or lightning surge impulse, can vary widely depending on factors such as the characteristics of the lightning discharge, the proximity of the lightning strike to the point of measurement, and the type of electrical system being affected. Lightning impulses are characterized by their extremely high peak voltages and fast rise times.
Typically, lightning impulses can have peak voltages ranging from tens of kilovolts to several hundreds of kilovolts or even megavolts. Lightning strikes can generate voltage impulses with peak values in the range of 100 kV to 1 MV or more.
For example, a typical lightning impulse voltage waveform might have a peak value of around 100 kV to 200 kV and a rise time of microseconds or less. However, in extreme cases, such as direct lightning strikes to power lines or substations, the peak voltage of the lightning impulse can exceed several megavolts.
It's important to note that lightning impulses are transient events with rapidly changing voltage characteristics, and they can cause significant damage to electrical systems and equipment if not properly protected against. Electrical systems and equipment are often designed and tested to withstand lightning impulses and other transient overvoltages to ensure their reliability and safety.