Frequency Responses of Wind Turbines with Magnetic Speed Reduction in Autonomous Power Systems

The present paper is devoted to investigations of the influence of the initial response of wind energy and its importance for system reliability. This problem is especially relevant for autonomous power systems with wind turbines. The energy stored in rotating masses of wind turbines and inertial wind energy contribute to the power system inertia. It was found that the decrease of system inertia in the case of higher levels of renewable generation does not have a significant influence on frequency responses in comparison with the regulator action. Wind turbines contribute to the inertial and primary frequency response during the frequency drop in the power system. However, the fast support for the changing frequency with the controlled inertia of wind energy will facilitate the return of the frequency to the normal operating range that allows avoiding load disconnection at low frequencies in the system. The paper also presents comparative characteristics of frequency responses for a wind turbine with a magnetic gearbox and a mechanical gearbox. The aim of the study is to analyze and give a quantitative estimation for frequency responses of wind power plants having various technologies of turbines and transmissions, namely variable-speed of wind wheel rotation, magnetic speed reduction and a synchronous generator with permanent magnets.