Frequency responsive wind plant controls: Impacts on grid performance

Grid integration of wind power plants is complicated by a number of issues, primarily related to wind variability and the electrical characteristics of wind generators. Frequency control is a particularly significant issue with high levels of wind and solar penetration. A typical wind plant appears to the grid as a substantially different generation source than a conventional power plant. A significant difference is that the wind energy source is inherently uncontrollable. In addition, the electrical characteristics of wind generators result in a disturbance response that is naturally different from that of conventional synchronous generators. Without special controls, a wind plant does not inherently participate in the regulation of grid frequency as do synchronous machines. And, when wind generation displaces conventional synchronous generation, the burden of frequency regulation placed upon the remaining synchronous generators is increased. The paper summarizes results from a recent investigation of system frequency response in the Western US as it may be affected by large amounts of wind generation. Impacts and benefits of wind plant controls that provide frequency response are illustrated with quantitative examples. Both inertial and primary frequency response behaviors are examined.