Influence of the CIGRE lightning current waveform implementation on ATP-EMTP simulations of lightning strikes to a 150 kV overhead transmission line

The lightning current waveform proposed in the CIGRE Technical Brochure 63 is commonly used for simulating lightning strikes to grounded objects. The generation of a specific CIGRE waveform requires solving a nonlinear equation, which does not have a unique solution. This may lead to inconsistent and/or erroneous waveforms affecting simulation results. This work investigates the influence of the CIGRE waveform implementation on ATP-EMTP simulations of lightning strikes to a 150 kV double-circuit overhead transmission line. Three implementations are considered: (i) the approximate CIGRE expressions, (ii) the CIGRE type 15 source of ATP-EMTP, and (iii) a practical approach using polynomials to calculate the required constants of the CIGRE waveform for a specific peak current. Simulation cases comprise several tower ground resistance values and lightning strikes to the tower and upper phase conductor.