By hvhipot 
The lightning impulse voltage generator under HV Hipot Electric Co., Ltd. power can help many power workers conduct various power tests more conveniently.
In simple terms, a Lightning Impulse Chopped Wave is an artificially “clipped” lightning impulse voltage wave.
It simulates a real-world scenario where a lightning or switching overvoltage wave, while propagating through a power system, suddenly collapses from its peak value due to an external event―typically the breakdown of an external insulation gap.
A chopped wave is essentially the standard full wave described above, but with the voltage abruptly and rapidly forced to zero at a certain point on its tail, usually near the peak.
Generation Method:In a laboratory, this is achieved using a chopping gap or a triggered switch. When the impulse voltage generator applies a voltage to the test object, a gap with a breakdown voltage set just below the expected withstand level of the test object is used. When the voltage rises to the gap’s breakdown voltage, the gap flashes over, creating a short circuit that “chops” the subsequent part of the voltage wave.
Waveform Characteristics:
It has the same wavefront (rising edge) as the full wave.
After reaching the peak (or sometimes just before), the voltage drops to zero very rapidly (typically in less than 0.5 microseconds).
This sudden collapse of voltage creates an extremely high rate of voltage change (dv/dt).
Notation: It is denoted by its time to chop, for example, “1.2/50 ~ 3 μs” describes a 1.2/50μs full wave that was chopped at approximately 3 microseconds.