Energy efficiency Improvement of Hydro and Thermal power plants in EPS by development and implementation of power electronics based regulation and automation equipment

The project primary target is the efficiency improvement of steam and hydro power plants by development and implementation of power electronics equipment for control and automation. In order to increase the availability of synchronous generator, an adaptive digital control structure will be applied in excitation control unit. Joint reactive power (joint VAR) control will optimize the produced reactive power within power plant while maintaining the maximal Q margin of each machine. Joint VAR control is especially suitable for multi machine hydro power plants connected to transmission network via long lines, due to improved stability. Also, a central synchronizing device for generators synchronization to network will be analyzed and improved. The main improvement issues are the higher equipment reliability and communication interfaces. The DC uninterruptible power supply system will be analyzed and improved by connecting more rectifiers in appropriate way to increase redundancy and reliability, according to specific plant requirements. Also, the AC uninterruptible power supply system will be analyzed and improved, by connecting more inverters as synchronized warm reserve, once again to get more reliable AC voltage for control and command. Finally, the high speed transfer device, for commanding with medium voltage (MV) breakers of internal motor MV bars of steam power plant in order to transfer motor MV bus bars to auxiliary supply will be improved and fully digitalized.