Comparison of Bergeron and frequency-dependent cable models for the simulation of electromagnetic transients

The simulation of electromagnetic transients involving underground cables is very time consuming, when compared with simulations involving overhead lines, and Bergeron models are often used instead of the more accurate frequency-dependent models, in order to reduce the simulation time. This paper analyses the simulation errors of different Bergeron models to a reference frequency-dependent model for a 150kV cable. The simulations consider flat and trefoil installation, both-ends bonding and cross-bonding, ideal voltage source and modelling of the area around the cable. The Bergeron model is simulated for three different target frequencies: transient's resonance frequency, 50Hz and an in-between frequency. The results are analysed theoretically using modal propagation theory and the error is quantified for the case under examination. It is concluded that for a realistic case, which requires the modelling of the area around the cable being energised, the Bergeron model has a small error if tuned for the right frequency.