A potential security threat and its solution in coupled urban power-traffic networks with high penetration of electric vehicles

Abstract

The growing penetration of electric vehicles (EVs) and the popularity of fast charging stations (FCSs) have greatly strengthened the coupling of the urban power network (PN) and traffic network (TN). In this paper, a potential security threat of PN-TN coupling is revealed. Different from traditional loads, a regional FCS outage can lead to both the spatial and temporal redistribution of EV charging loads due to EV mobility, which further leads to a power flow redistribution. To assess the resulting potential threats, an integrated PN-TN modeling framework is developed, where the PN is described by a direct current optimal power flow model, and the TN is depicted by an energy-constraint traffic assignment problem. To protect the privacy of the two networks, an FCS outage distribution factor is proposed to describe the spatial-temporal redistribution ratio of the charging load among the remaining FCSs. Moreover, to protect the security and efficiency of the coupled networks, a price-based preventive regulation method based on the spatial demand elasticity of the EV charging load is developed to reallocate the charging load as a solution to insecure situations. Numerical simulation results validate the existence of the PN-TN coupling threat and demonstrate the effectiveness of the regulation method to exploit the spatial flexibility of EV loads.