The aim of this thesis is to determine if the way the zero phase sequence impedance is calculated by Nyfors A/S today is accurate enough, and if not give new recommendation on how to obtain the positive- and zero phase sequence impedance. It is done by creating a model in PSCAD, which is validated by a set of measurements made on a 60kV cable owned by Nyfors A/S. The parameters of the model were tested in order to see which had influence on the zero phase sequence impedance and which have influence on the positive phase sequence impedance.
The guidelines at the end of the report are based on the model and the measurements.