A Novel Method to Valorize Frequency Support Procurement by Wind Power Plants

Abstract

The provision of frequency support by renewable power is a key challenge to allow higher penetration of renewables. While the research efforts focus on proposing new control methods and market structures to realize and facilitate the provision of frequency services by wind power, less attention is given to financial compensation of proper responses. This paper proposes a comprehensive method to evaluate the net payments to participating wind power plants, including a penalty factor for responses that do not comply with grid codes and market bids. This method integrates frequency data and dynamic response of wind power assets during the events, to evaluate the compliance level under a certain grid code, and calculates the corresponding net payment. The paper demonstrates the method by integrating the worst frequency event in each month from the real recorded data of UK National grid frequency response in 2016. The results obtained show clear diversities between the three examined support methods with clear influence of the incident wind speed. Kinetic energy extraction support method shows a little merit at high wind speeds, while pitch deloading method performs better at the majority of the examined case studies. Index Terms-Wind power plants, ancillary services, frequency stability, grid codes, reserve markets. I. NOMENCLATURE ∆E Energy support during frequency event [MWH] ∆P5, ∆P30 Average power support within 5s and 30s [MW] ∆Pa Actual power support [MW] Aδ Tolerance factor [-] CF Capacity factor [-] CP, CE Power and energy prices [€/MW, €/MWH] DF Deloading ratio [-] flow Frequency violation threshold [Hz] f m d

Economic Model of Ancillary Services in Real Time for Frequency Control

“…In ref. [25], a real-time integral postoperation method is proposed that minimizes the gap between the net payments of power plants and a penalty factor at different time scales (5 s, 15 s, up to 60 s) when they do not meet the market bids at the time of allocating frequency regulation. Both methods are effective when applied to supply the demand, and the minimum hourly reserves are not met in the scheduled dispatch.…”

Impact of Frequency Support by Wind Turbines on Small-Signal Stability of Power Systems

“…Through specific controls, the kinetic energy can be extracted and provided to the system when needed. Available methods to supply inertial and primary frequency support include, among others, kinetic energy extraction, pitch de-loading or accelerative de-loading [30].…”

The Impact of Frequency Support by Wind Turbines on the Small-Signal Stability of Power Systems

“…Through specific controls, the kinetic energy can be extracted and provided to the system when needed. Available methods to supply inertial and primary frequency support include, among others, kinetic energy extraction, pitch de-loading or accelerative de-loading [31].…”