1.Engineering Research Center of Offshore Wind Technology, Ministry of Education (Shanghai University of Electric Power), Shanghai 200090, China;2.Lijin Power Supply Company, State Grid Shandong Electric Power Company, Dongying 257000, China

Multiple virtual power plants (VPPs) participating in the joint market as a cluster can enhance their market competitiveness. To solve the resource allocation of the cluster in the multi-market coupling decision-making and balance the electric power energy and the frequency regulation revenues, this paper proposes a bidding strategy of VPP clusters participating in the electric power energy market and frequency regulation market. Firstly, an internal transaction mode between the VPP and the cluster operator is proposed, and a pricing strategy for the cluster operator and a method for refining the response behavior of the VPP when participating in the external joint market are designed. Secondly, an operation cost model of VPP considering the electric power energy and frequency regulation capacity transaction is established to realize multi-product transactions in the cluster, providing a foundation for the operator to formulate bidding strategies for the joint market. Then, the price quota curve is adopted to characterize the relationship between clearing results of the frequency regulation market and the bidding strategy, and a risk-averse optimal bidding strategy is proposed with the objective of maximizing cluster revenues. Finally, a simulation analysis is conducted on a cluster consisting of three VPPs. The case study results demonstrate that the proposed joint bidding strategy stimulates the response willingness of each VPP and improves the economic revenue of the cluster.