An Energy-Efficient Start-Up Strategy for Large Variable Speed Hydro Pump Turbine Equipped with Doubly Fed Asynchronous Machine

The use of a Doubly Fed Asynchronous Machine (DFAM) provides attractive characteristics and offers operational flexibility in many variable speed generation applications, such as hydroelectric pumped storage plant. In plant, the start-up process DFAM is identical to conventional singly fed asynchronous machine, wherein significant amount energy wasted. This paper introduces an energy-efficient strategy based pump-turbine. back-to-back voltage source converter connected rotor side amenable for control (real power), braking (regenerative/dynamic), starting unit. Further, this technique, stator circuit machine injected with low DC supply at instead short-circuiting windings. injection reduces slip losses cuts down magnetizing current requirement. magnitude required estimated on machine’s reactive power Also, switching winding between short connection, injection, grid carried out using changeover switch determined by rotor. proposed investigated 250 MW Matlab/Simulink environment experimented 2.2 kW prototype. Test results show that method can conserve more than 26.1 percent electrical example application compared V/f strategy.