Power system simulation using digital filter structures

The simulation of power systems for protection applications is developed based on digital filtering techniques. Although transmission lines are easily modeled by digital filters, lumped elements suffer severely in this process, resulting in large distortions or high sampling rates. Furthermore, the interconnection of digital filter models is usually noncausal due to the presence of delay-free-loops in the structure. This work deals with the causality problem and with the modeling of lumped networks. Two approaches are suggested for this modeling, the first involving approximation techniques and the second based on a multirate interpretation of the bilinear transform. Comparative examples are included