Technology Summary on the Application of Variable-Speed Pump-Turbine Units for Wind Storage Operation

Variable-speed pump-turbine units are used as the large capacity flexible and fast storage system for peak and frequency modulation in grid. There are several advantages as follows: the total energy conversion efficiency is nearly 80%. The modulation performance that ms-level time can be achieve MWlevel power response. Possibility of active power control in pumping mode. In the generating mode, the range of unit output is wide than conventional units. With the help of flywheel effect, network stability improvement by instantaneous active power injection in the grid. Summing up the above, variable-speed pump-turbine units are useful in concentration area of wind power and other new energy. And it can be used to solve the problem of large-scale wind power integration. The operation characteristics of Variable-speed pump-turbine units and the operation characteristics of wind power output is taken into account in this paper. Variable-speed principle, physical operating characteristics, operating parameters and economic investment of variable-speed pump-turbine units is presented. And the combined operation technology of variable-speed pumpturbine units and wind power is summarized.