Modelling DC offset in fault currents recorded by intelligent electronic devices

An adaptive parameter estimation algorithm in the Laplace Transform domain is presented. It can be used to estimate transmission network Electromagnetic Transient equivalents from fault records. The algorithm is applied in modeling exponentially decaying DC offset of recorded fault currents. This information is of great importance in determining fault levels, in protection system design as well as in power system model validation. Accuracy of the algorithm is demonstrated by using simulation and laboratory experiments.