Guidelines resulting from modeling, evaluation and coordination enhancement of Itaipu hydro power plant protection

Generator protection misoperations may intensify a disturbance or even lead the power system to a major outage, especially when it occurs in a large power plant. Additionally, the power system expansion changes the short circuit currents and, thus, from time to time the system requires a re-evaluation of protection coordination. In this paper, Itaipu power plant's modeling, analysis and coordination evaluation of the protection functions performed due to scheduled technological update are presented. Lessons learned and undesirable situations concerning operation of large generators connected to large transmission systems observed during this process were used to propose a set of guidelines for overexcitation protection coordination evaluation for generators with the same type of configuration.