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OPTIMAL PORTFOLIO AND BIDDING STRATEGY FOR DER AGGREGATORS PARTICIPATING IN VARIOUS ANCILLARY SERVICES TRANSACTIONS

As one of the most important entities trading in the ancillary services market, the distributed energy resources (DER) aggregators can bid in the market via aggregating the available capacity of the DER. It is essential for the DER aggregators to bid in an optimal way so as to maximize their profits. Heretofore, however, most of the existing studies focus on the issue that the DER aggregators just utilize a single type of DER to participate in a single breed of ancillary service transaction, which cannot fully explore the potential of DER participating in ancillary services market and expand the profit space of the DER aggregators. To this end, this paper proposes an optimal bidding strategy for the DER aggregators participating in different kinds of ancillary services transactions with various DER which include energy storage system (ESS), electrical vehicle (EV), distributed generation (DG), and demand response (DR). Firstly, the characteristics of different kinds of DER and ancillary services are analysed. Secondly, based on the characteristic analysis results, an optimal classification and portfolio method for these DER participating in different kinds of ancillary services transactions is proposed. The uncertainty of market prices is considered, and the optimal bidding model is constructed by using stochastic programming aiming at maximizing its expected profit. Finally, the effectiveness of the proposed model is verified by a simulation based on the PJM trading rules.