A two-stage robust optimization for EV user-friendly VPP participation in ancillary service markets

With the integration of distributed energy resources and loads into distribution networks, issues of voltage violation and peak shaving have escalated. Consolidating these resources into virtual power plants (VPPs) for ancillary service market participation as a unified entity is seen as an effective solution. However, consensus on how VPPs should engage in voltage regulation within distribution networks remains elusive. Existing research often assumes unconditional execution of VPP directives by internal resources, neglecting the need to balance battery degradation among EV users, which can compromise fairness and user-side enthusiasm for participation. To address these issues, this paper proposes a two-stage robust game approach for EV user-friendly VPP participation. The approach adopts a Stackelberg game model (SGM), where the distribution network acts as the leader, setting compensation prices based on ancillary service market demand while ensuring grid safety, and the VPP as the follower, minimizing operational costs. The VPP ensures reserves to swiftly respond to market uncertainties. A power allocation strategy was implemented based on a consensus algorithm that takes into account the satisfaction level of EV users participating in ancillary services and the battery degradation cost. Case studies demonstrate that the approach flexibly addresses diverse market demands, mitigates voltage violations, regulates peak-to-valley differences (PVD), and fairly distributes user-side participation losses.