Coordinated control of distribution grid and electric vehicle loads

Electric vehicle (EV) charging results in unusual power peaks during low energy prices, which can have adverse impacts on distribution grid operation. Therefore, coordinated dispatch of EV loads including the operational constraints of distribution grid is essential. However, a centralized approach to solve this problem is computationally challenging task. This work proposes a bi-level hierarchical vehicle-grid (VG) optimization framework. In the hierarchy, optimal operation of the distribution grid is considered in one level, while the optimal operation of EVs is carried out in another level. The proposed framework consists of comprehensive mathematical modelling of distribution system components, EVs, and operational constraints. The proposed framework is applied to coordinate charging of hundreds of EVs in the IEEE 34-node three-phase unbalanced distribution system. Case studies demonstrate that the hierarchical VG optimization framework provides benefits to the distribution grid operations as well as to the EV owners.