Bi-level power management strategy in harmonic-polluted active distribution network including virtual power plants

In this paper, a bi-level power management strategy is presented for an active distribution network (ADN) in the presence of virtual power plant (VPP). In the proposed strategy, VPP contains renewable energy source (RES), energy storage system (ESS) and electric vehicles (EVs) parking lot coordinated with VPP operator (VPPO), and there is a coordinated framework between VPPO and distribution system operator. The proposed power management strategy (PMS) is considered in the context of the bi-level optimization problem. In the first level, the optimal harmonic power flow formulation of the ADN is considered by minimizing the summation of energy cost, voltage deviation function and voltage THD% as a normalized objective function. In the second level, the VPP is modeled according to the framework of day-ahead energy and ancillary services markets. In the next step, the linear format of the proposed non-linear original problem is obtained with an optimal solution and low calculation burden. Also, the Karush-Kuhn-Tucker condition is used to convert the proposed bi-level PMS approach to a single-level model, and the scenariobased stochastic programming models the uncertainty of load, energy price, RES power, and EVs demand. Finally, the proposed strategy is applied on the 33-bus distribution network using GAMS software.