Usage of direct search methods in predictive control of ancillary services

Most European transmission systems are interconnected to ensure the reliability and accessibility of electric power supply. Transmission system operators (TSOs) are responsible for ensuring that contracted cross-border supplies are available and that deficits are accommodated. TSOs typically buy ancillary services in advance for use in periods of deficit. This paper described a predictive control approach for ancillary services in interconnected electricity systems. The model was designed to predict the difference between contracted and actual cross-border transmission of electric power. The power sources were considered as individual power plants. The receding horizon principle was applied in order to compute the time sequences of individual sources for longer prediction periods using only the initial part of the sequences. Coverage included positive tertiary regulation; negative tertiary regulation; quickstart; dispatch reserve; and energy bought from other countries. Inputs were converted into binary values for the optimization algorithm. The technical properties of individual sources were used as fundamental constraints. The optimization algorithm was able to determine optimal sequences of ancillary services within a prediction horizon of 6 hours. 6 refs., 1 tab., 6 figs.