Modelling issues of system protection schemes in energy management systems

As more and more utilities are using / examining use of System Protection Schemes (SPS), also referred as Remedial Action Schemes (RAS), Energy Management System (EMS) vendors started looking at SPS schemes more seriously in their solutions. Formal tools are beginning to show up in the EMS industry. An important aspect in such efforts, is modelling of SPS schemes. In this paper the authors share their experience on modelling aspects of SPS, based on the experience gained while implementing Energy Management Systems in their new System Control Center. Issues in simulation of SPS in cascade, issues of modelling the transmission equipment by "circuit breaker" model versus \´Line Section\´ model and the issues of modelling time delay are discussed. Issues of certain EMS applications dealing with RAS are discussed. The authors also summarized important elements to be considered while drawing out EMS requirements for supporting SPS.