Fast frequency response constrained electric vehicle scheduling for low inertia power systems

Abstract

Reduction in System Inertia (SI) and Primary Frequency Response (PFR) driven by the large-scale integration of uncertain and variable Renewable Energy (RE) sources disturbs the post-fault frequency dynamics. This necessitates the identification of potential solutions that can restrict high Rate of Change of Frequency (RoCoF). Electric vehicles (EVs), due to their fast response capability and instantaneous power delivery, are a viable source for the Fast Frequency Response (FFR) service. Potential assessment of EVs for FFR service is required to restrict high RoCoF and maintain secure and reliable system operation in real-time. The main contribution of this work is to assess the potential of EVs for FFR support through both Grid-to-vehicle (G2V) and Vehicle-to-grid (V2G) modes. In this work challenges like EVs aggregation, related netload uncertainty characterization, and post-fault frequency dynamics are modelled in a stochastic security-constrained scheduling framework. Further, a case study is carried out to investigate the role of EVs and their techno-economic impact on the overall system: (a) only in dumb charging mode and (b) participating in FFR service by scheduling aggregated EVs for both G2V and V2G with different level of RE integration. Numerical results indicate that the aggregated EVs scheduling can provide FFR support of around 71%, by simultaneously reducing system operating cost by 62% and 87% reduction in RE curtailment.