Control Algorithm for Parallel Connected Offshore Wind Turbine Generators

A control algorithm for Parallel Connected Offshore Wind Turbines with permanent magnet synchronous Generators (PCOWTG) is presented in this paper. The algorithm estimates the optimal collective speed of turbines based on the estimated mechanical power of wind turbines without direct measurement of wind speed. In the proposed topology of the wind farm, direct-drive Wind Turbine Generators (WTG) is connected to variable low-frequency AC Collection Grids (ACCG) without the use of individual power converters. The ACCG is connected to a variable low-frequency offshore AC transmission grid using a step-up transformer. In order to achieve optimum wind power extraction, the collective speed of the WTGs is controlled by a single onshore Back to Back converter (B2B). The voltage control system of the B2B converter adjusts voltage by keeping a constant Volt/Hz ratio, ensuring constant magnetic flux of electromagnetic devices regardless of changing system frequency. With the use of PI pitch compensators, wind power extraction for each wind turbine is limited within rated WTG power limits. Lack of load damping in offshore wind parks can result in oscillatory instability of PCOWTG. In this paper, damping torque is increased using P pitch controllers at each WTG that work in parallel with PI pitch compensators.

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A New Control Algorithm for Directly Interconnected Offshore Wind Turbine Generators

2019 54th International Universities Power Engineering Conference (UPEC) ◽

10.1109/upec.2019.8893469 ◽

2019 ◽

Author(s):

Emir Omerdic ◽

Jakub Osmic ◽

Daniel Toal ◽

Cathal W. O'Donnell

Keyword(s):

Wind Turbine ◽

Control Algorithm ◽

Offshore Wind ◽

Offshore Wind Turbine ◽

Turbine Generators ◽

Wind Turbine Generators

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Performance Study of Wind Turbine Generators

Solar Energy ◽

10.1115/isec2003-44216 ◽

2003 ◽

Author(s):

G. R. Bhagwatikar ◽

W. Z. Gandhare

Keyword(s):

Power Consumption ◽

Wind Turbine ◽

Wind Power ◽

Wind Turbines ◽

Reactive Power ◽

Variable Speed ◽

Turbine Generators ◽

Wind Turbine Generators ◽

Utility Grid ◽

Operational Issues

It is well known that the wind power has definitely certain impact on the grid power. Issues associated with the integration of wind power into the utility grid are interface issues, operational issues and planning issues. Interface issues include harmonics, reactive power consumption, voltage regulation and frequency control. Operational issues are intermittent power generation, operating reserve requirements, unit commitment and economic despatch. And planning issues are concerned with intermittent wind resources compared to conventional power resources. An important question, when connecting the wind turbine generators to the utility grid, is how much the power / voltage quality will be influenced, since the power production by wind turbines is intermittent, quantity wise as well as quality wise. This paper is focused on the on comparison between the constant speed wind turbines and variable speed wind turbines, reactive power consumption and harmonics generated by both wind turbines. Total harmonic distortion is calculated by the application of C++ software and a comparison is done between the generators with respect to the harmonics. It is observed that constant speed wind turbine generates low order harmonics and variable speed turbine generates high order harmonics. On the basis of results, some solutions are suggested to improve the wind power quality and to reduce reactive power consumption. It seems that variable speed wind turbines with electronic interface are better with respect to the utility grid point of view.

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