A Bilevel Programming Model of Electric Vehicles’ Aggregator for Bidding Strategy in the Distribution Network

In this paper, a bidding strategy model is presented for electric vehicles’ (EVs) aggregator to sell the aggregated energy in the distribution network. The bidding price of the EVs’ Aggregator is determined through the Stackelberg game theory. It is modeled based on a bilevel programming problem between distribution system operator (DSO) and the aggregator. In the upper level of proposed bilevel model, the aggregator offered its optimal bidding price and EVs’ charge and discharge scheduling to maximize its profit. On the other hand, according to the price of the electricity market and bidding by the aggregator, DSO tries to optimally schedule the portion of energy which is supplied from either main grid or EVs’ aggregator to minimize its cost. In the equilibrium point of the problem, the optimal bidding price of the aggregator and the purchased energy from the aggregator and main grid is determined. The proposed bilevel programming problem is transformed into a single level mathematical programming problem with equilibrium constraints (MPEC) using the Karush-Kuhn-Tucker optimality conditions. The obtained numerical results is used to assess the proposed bidding strategy of EVs’ aggregator.