More than power from wind: Emperical data from a wind farm providing power-frequency response and automatic generation control

Abstract

Modern wind turbines are capable of providing more than low-cost energy - they are able to provide a wide array of ancillary services that can contribute to the stability of a changing grid. This work evaluates the performance of Enercon's E-82 wind turbines in providing two ancillary services - power-frequency response (frequency-watt response) and automatic generation control (AGC). Empirical data is gathered at the 50.6 MW Nuttby Mountain wind farm in Nova Scotia, Canada that consists of twenty two IEC Type 4 turbines. AGC data is from the entire farm responding as a single unit while power-frequency data is from a single wind turbine. We document and analyse the wind farm's ability to curtail power output in response to grid frequency increases at varying power levels and also present forty five minutes of AGC data. Empirical data such as these are useful to system operators in determining how to best utilise their existing wind power fleets. We report good performance with both ancillary services. Mean error for the power-frequency data is approximately 2% of rated turbine power. Performance scores for AGC are 97% via the California ISO method and 87% via the Midcontinent ISO method.