Abstract
EDF R&D branch and Basic Design department (SEPTEN) are currently working on an innovative methodology to provide an electric overpower to PWRs having feedwater tank and under frequency control operation. This paper presents the principles and the first simulation results of this new control, named "PARI", in various cases. It also presents a statistical analysis of the 50 Hz European frequency grid behavior in order to give elements to evaluate the risk of reaching extreme levels in the feedwater tank or in the condenser, and then to stop providing a part of the contractual power reserve. Thanks to this new control it appears that the power set point could be increased by 0.5 to 1% of Nominal Power, considering the few months of frequency data availability. This overpower can only be obtained from PWRs having a feedwater tank with a sufficient volume (34 among the 58 French plants) and when under frequency control operation (about one third of operation time). A financial evaluation based on the elements mentioned above comparing gains and costs, like changing the control hardware, has shown the interest of this proposal. Grid safety is the other decisive element for the wide spread use of this new methodology. Thus not only producers but also regulation authorities have to discuss on the acceptability of such an innovation. The "PARI" project is still under development and decision of testing out or not the new controller should be taken soon. Any company, authority, institute or agency interested in the project is welcome to contact EDF.
