A method for controlling an electrical power system connected to an electrical grid having a generator and a power converter includes monitoring a speed condition of the electrical power system. The method also includes dynamically determining at least one regulator maximum limit for at least one regulator of the power converter based on the monitored speed condition. Further, the method includes operating the at least one regulator based on the at least one dynamic regulator maximum limit to avoid overmodulation of the electrical power system during high-slip operation and to improve sub-synchronous control interaction (SSCI) performance of the electrical power system.

Techniques for controlling rotor speed of a wind turbine. One technique includes defining a system model describing resonance dynamics of a wind turbine component, such as a wind turbine tower, where the system model has a nonlinear input term, e.g. a periodic forcing term. A transform is applied to the system model to obtain a transformed model for response oscillation amplitude of the wind turbine component, where the transformed model has a linear input term. A wind turbine model describing dynamics of the wind turbine is then defined, and includes the transformed model. A model-based control algorithm, e.g. model predictive control, is applied using the wind turbine model to determine at least one control output, e.g. generator torque, and the control output is used to control rotor speed of the wind turbine.

The invention concerns a method for coupling a hydroelectric power plant in a turbine mode to a grid, in order to generate power for a grid, said hydroelectric power plant comprising at least a first hydroelectric unit (10) and a second hydroelectric unit (100), each provided with a runner (6) mechanically coupled to a shaft line (8) and to a generator, a distributor (4) comprising guide vanes to control a flow of water to said runner, said hydroelectric power plant further comprising a variable frequency drive (20), the method comprising: a) starting the rotation of at least said first hydroelectric unit (10) and said second hydroelectric unit (100); b) connecting the variable frequency drive (20) to the generator of the first hydroelectric unit (10) and to the grid and stabilizing the speed of the first hydroelectric unit c) connecting the first hydroelectric unit (10) to the grid and disconnecting the generator of the first hydroelectric unit from the variable frequency drive (20); d) connecting said variable frequency drive (20) to the generator of the second hydroelectric unit (100) and to the grid and stabilizing the speed of the second. hydroelectric unit; e) connecting the second hydroelectric unit (100) to the grid and disconnecting the generator of the second hydroelectric unit from said variable frequency drive (20).

The invention relates to a method and a system for adjusting the torque of a mass and spinning wheel rotator in a wave power plant. The torque of a rotator rotating around a vertical shaft is compensated partially or completely with a compensating moment which is produced by an electric machine. Acceleration components (.sup.ACCx and .sup.ACCy) are measured for a given point of the wave power plant's floating body (1) in directions perpendicular to each other. A vector (V.sub.xy) with a magnitude formula (A) and a direction (a.sub.Acc) is established for said acceleration components, the direction or angular position (a) of a rotator (2) is monitored and its lag (α.sub.LAG) from the acceleration vector's direction (α.sub.Acc) is determined. The compensating moment is adjusted as dependent on a compensation factor (B) whose sub-factors are the magnitude of the body's acceleration vector (V.sub.xy) and the sine of the angle of lag (sin α.sub.LAG). This is supplemented with a compensation factor based on spinning wheel forces in a manner otherwise similar except that the acceleration must be replaced with a rotation speed (AV.sub.x-y) of the body's inclination, which is obtained from an inertial sensor 821). and the mass must be replaced with a gyro force which is dependent on the inertia and rotating speed of a spinning wheel.

The invention relates to a method for controlling a wind turbine in partial and full load. In order to avoid disadvantages of switching between partial and full load controllers, the wind turbine control system is configured so that both the partial and full load controller provides control action during partial and full load. For that purpose, the partial and full load controllers are configured with variable gains, wherein gain scheduling is performed so that the gain of partial load controller is larger than the gain of the full load controller during partial load and vice verso so that the gain of the full load controller is larger than the gain of the partial load controller during full load.

A method and an apparatus for controlling noise of multiple wind turbines. The method includes: determining a noise-influencing sector of each of the multiple wind turbines, based on positions of the multiple wind turbines and a position of a noise-influencing site; acquiring a current wind direction; determining whether there is at least one wind turbine of the multiple wind turbine under the current wind direction operating in the noise-influencing sector; and limiting output power of the at least one wind turbine, in a case that the determination is positive.

A startup method of a Francis turbine according to an embodiment includes: a first rotation-speed increasing step in which a rotation speed of the runner is increased by opening the guide vane at a first opening; a second rotation-speed increasing step in which the increase in the rotation speed of the runner is accelerated by opening the guide vane at a second opening that is larger than the first opening after the first rotation-speed increasing step; and a rotation-speed regulating step in which the rotation speed of the runner is regulated to a rated rotation speed by opening the guide vane at a no-load opening after the second rotation-speed increasing step. The first opening is an opening that is half or less than the no-load opening.

A method for in-place machining of a collector ring attached to a turbine shaft of a hydroelectric generator includes: attaching a support member to stationary portions of the hydroelectric generator, the support member being configured to support a machine tool at an angle parallel to an inclination angle of an axis of rotation of the turbine shaft; attaching an adjustable positioning device to the support member; attaching the machine tool to the adjustable positioning device, the machine tool being configured to perform a machining operation on the collector ring; controlling a rotational speed of the turbine shaft to a specified rotational speed by controlling a flow of water through the turbine; adjusting the adjustable positioning device to adjust a position of the machine tool with respect to the collector ring; and performing the machining operation on the collector ring at the specified rotational speed of the turbine shaft.

A rotation speed avoidance control method for a wind turbine generator system. The method comprises: when a power-limited operation instruction is received, determining a power value upper limit required by the instruction: determining whether the required power value upper limit is in a power avoidance interval corresponding to a rotation speed avoidance interval; and when the required power value upper limit is in the power avoidance interval, setting the maximum allowable power value of a wind turbine generator system to be a lower boundary value of the power avoidance interval. An upper boundary value of the power avoidance interval is a power value determined on the basis of an upper boundary value of the rotation speed avoidance interval, and the lower boundary value of the power avoidance interval is a power value determined on the basis of a lower boundary value of the rotation speed avoidance interval, wherein the rotation speed avoidance interval and the power avoidance interval are open intervals. By means of the control method, an operation range of the rotation speed of a wind turbine generator system in a power-limited operation state can be prevented from overlapping with a rotation speed avoidance interval, thereby preventing resonance of the generator system, load increase or other safety problems. In addition, the present invention further relates to an apparatus for implementing the control method, and a wind turbine generator system.

A method for operating a wind turbine for generating electrical power from wind, wherein the wind turbine has an aerodynamic rotor with a rotor hub and rotor blades of which the blade angle is adjustable, and the aerodynamic rotor can be operated with a variable rotation speed, and the wind turbine has a generator, which is coupled to the aerodynamic rotor, for the purpose of generating a generator power, wherein the generator can be operated with a variable generator torque, comprising the steps of: determining a loading variable which indicates a loading on the wind turbine by the wind, and reducing the rotation speed and/or the generator power in a loading mode depending on the loading variable, wherein at least one force variable that acts on the wind turbine is used for determining the loading variable or as the loading variable.