Interactive protection operation analysis in complex power systems

In the paper, the interaction of numerical protective relays with a complex power system operation during transients and faults is studied. The presented approach, which incorporates the analysis of pre- and post-fault conditions as well as those during transients, enables a deeper insight in the protection operation and allows more accurate parameter settings. Additionally it offers a practical tool for checking the existing and new protection schemes. As an example the dynamical model of the Crete power system was used in the authors´ simulations. The Crete power system is an autonomous medium-sized power system, comprising power generation of various types including renewable and high voltage transmission. Essentially new numerical differential and conventional distance relays were modelled to demonstrate the benefits of the proposed integral approach.