Vattenfall

About: Vattenfall is a company organization based out in Stockholm, Sweden. It is known for research contribution in the topics: Wind power & Combustion. The organization has 685 authors who have published 857 publications receiving 18912 citations. The organization is also known as: Vattenfall AB & Kungliga Vattenfallstyrelsen.

Measurement of rotor centre flow direction and turbulence in wind farm environment

Abstract: The measurement of inflow to a wind turbine rotor was made with a spinner anemometer on a 2 MW wind turbine in a wind farm of eight wind turbines. The wind speed, yaw misalignment and flow inclination angle was measured during a five months measurement campaign. Angular measurements were calibrated by yawing the wind turbine in and out of the wind in stopped conditions. Wind speed was calibrated relative to a met mast in a wake-free wind sector during operation. The calibration measurements were used to determine the basic k1 and k2 constants of the spinner anemometer and a four parameter induction factor function. Yaw measurements and turbulence measurements, where the average wind speed was corrected to the far field with the induction function, showed good correlation with mast measurements. The yaw misalignment measurements showed a significant yaw misalignment for most of the wind speed range, and also a minor symmetric yaw misalignment pattern. The flow inclination angle showed slight variation of inflow angle with wind speed and clear wake swirl patterns in the wakes of the other wind turbines. Turbulence intensity measurements showed clear variations from low turbulence in the wake-free wind sector to high turbulence in the wakes of the other wind turbines.

Zoning principles in electricity distribution and energy production environments

Abstract: Because of the technological change and increased integration, Industrial Automation and Control Systems (IACS) are more and more exposed to threats which aggravate intentional and unintentional risk scenarios. This paper defines zoning principles for electricity distribution and energy production environments based on a Zone model, assessment methods, and security controls. The zoning principles are designed to mitigate these risks and to enable the secure integration of IACS in business processes according to international standards and best practices.

Dynamic capacity rating for wind cooled overhead lines

Abstract: This paper shows that with presently applied static capacity rating for overhead lines there is a high unutilized capacity a large percentage of the time. The possibility for applying dynamic line rating in order to reduce or postpone reinforcements of overhead lines using weather measurements in the power line corridor and thus not causing delays for the wind power planners is assessed in this paper. Very few occasions of low wind cooling in the power line corridor at the same time as high wind at nacelle height have been observed. (4 pages)