System and method for operating a pumped storage power plant with a double fed induction machine

A system for operating a pumped storage power plant with a double fed induction machine including a stator, which is directly connected to an electrical grid, and a rotor, which is directly connected to an electrical grid via a converter, and with a pumping/turbine device, which is drivingly connected to a double fed induction machine,

• wherein the system includes:
• a sensor device for measuring current operating variables, including currents (iS, iR) and voltages (uS) in a stator circuit and a rotor circuit;
• and
• a control device for the control of the operation of the pumped storage power plant, which is communicatively connected to the sensor device and is adapted to
• determine a current target value for a rotor current frequency or a mechanical speed of the rotor based on a target power to be transmitted between the electrical grid and the double fed induction machine depending on the measured actual operating variables,
• to determine one or more variables characterizing a current state of the pumped storage power plant,
• to determine a current inadmissible synchronous deadband ([Δf, Δf];
• [n0−Δn, n0+Δn]), which is determined by a permissible minimum required rotor current frequency (Δf) or speed difference (Δn) of the rotor speed from the synchronous speed (n0) for the stationary operation, depending on the one or more variables characterizing the current state of the pumped storage power plant,
• to control the converter in order to switch pulse-like sinusoidal voltages and currents with the current target value of the rotor current frequency to the rotor, if the current target value of the rotor current frequency or mechanical rotor speed does not fall stationary in the current inadmissible synchronous deadband ([−Δf, Δf];
• [n0−Δn, n0+Δn]).