Calibration of a 3 MV LI measuring system by comparison method and by numerical convolution using its measured step response

The dynamic errors of peak value uˆ, front time T₁ and time to half value T₂ of an approved 3 MV LI (lightning impulse) measuring system were experimentally determined for two standard LIs with uˆ=500 kV, T₁=1.2 μs±20% and T₂=60 μs by two different methods. The first method is according to the comparison of an Approved Measuring System with a 500 kV Reference Measuring System. The second method is the convolution of the normalized step response g(t) of the 3 MV system with the standard LI input voltage measured with the Reference Measuring System. Agreement within 0.5% for uˆ and within 1.2% for T₁ and T₂ was achieved