Frequency responsive controls for wind plants in grids with wind high penetration

The frequency behavior of North American grids has recently been the subject of considerably heightened concern. Reports to the North American Electric Reliability Corporation [1] show that “frequency response”, that is, the severity and recovery of grid frequency following large disturbances (typically trip of large thermal generation plants) has been declining over the past two decades. In Texas, ERCOT has moved to require that all wind plants be able to actively participate in the management of system frequency. While frequency responsive controls have been required in some systems (e.g. EirGrid) for many years, the new requirements in Texas represent a major change for North America. The paper summarizes results from recent development and refinement of wind plant and wind turbine levels controls as they relate to North American systems, and ERCOT in particular. Various options for impacting frequency response, including use of wind plant controls that provide frequency droop and inertial response are presented.