Intra-day markets have been set up in some power markets with large scale integration of wind power generation. Inspired by Spanish market, this paper proposes a modified intraday bidding mechanism to better accommodate stochastic wind energy. Then the coordinated operation of wind farm (WF) and pumped-hydro-storage plant (PHSP) is studied. Firstly, wind power forecast errors are classified according to forecast wind speed. The corresponding error distribution is represented by a versatile probability function, which is explicitly reversible. Secondly, a chance-constrained optimization formulation is proposed to obtain the optimal bidding strategy of WF and PHSP. Case studies and sensitivity analyses are carried out. Simulation results demonstrate that the intra-day bidding mechanism can effectively utilize the updated wind power forecast data, and the proposed optimization method can increase profit for the union of WF and PHSP.
Index Terms-intra-day bidding, optimal coordination, wind farm, pumped-hydro-storage plant, chance-constrained optimization, versatile probability function, wind power forecast error
I. NOMENCLATURE
Sets: I={1,2…s}Set of day-ahead wind power forecast scenarios.
K={1,2…24}Set of 10-min periods in the future 4-8 hours.
J={1,2…20}Set of 1-hour periods in the future 8-28 hours. Functions: ( ) Pr ⋅ Probability of given event ( ) E ⋅ The expectation of stochastic variable. ( ) K t S ⋅ The profit in interval t of set K. ( ) J t S ⋅ The profit in interval t of set J. ( ) t ξ ⋅ Random wind power output at the given forecast wind speed. Decision Variables: , w t i p Power generation of wind farm at interval t, scenarios i. .cn). , , , d c t i t i