U/Q capability diagram of large Turbogenerators - contractual agreements, operation and e-monitoring tools

In France, according to the ancillary services agreement between the generating companies and RTE (the French Transmission System Operator), voltage control performance is mainly evaluated according to the UQ (Voltage, Reactive power) capability diagram. EDF, the main French generating company, has provided the UQ diagram of its nuclear power plants derived from realistic PQ capability diagrams with, as far as possible, a validation with field tests. Moreover, EDF has developed tools to monitor demand. On the one hand, on line, for the operation shift team, to help them to meet demand, on the other hand, off line, using data historian, to e-monitor the performance of the power plant as regards UQ capability and the occurrence of stresses on the generator.