Optimal Dispatching of Distribution Network Considering System Flexibility and User Thermal Comfort

To solve the problem that the uncertainty of distributed generation output seriously affects the safe and stable operation of distribution network, heat load, as a potential flexibility resource, can improve flexibility and eliminate system fluctuation without increasing new equipment. Therefore, an optimal dispatching model of the distribution network is proposed in this paper to improve the system flexibility while ensuring human comfort and operation economy. Firstly, the virtual energy storage model and human thermal comfort model of electric water heater (EWH) and air conditioning (AC) load are established. Secondly, a flexibility evaluation method is proposed based on the virtual energy storage of heat load. Furthermore, to decrease comprehensive operation cost and increase system flexibility, a two-stage distributed robust optimal dispatching model, which considers three kinds of flexible resources of EWH, AC and gas turbine (GT) is constructed. Then, the norm is used to constrain the uncertainty probability of wind turbine and photovoltaic output, and the column and constraints generation (C&CG) algorithm is used to solve the model. Finally, a simulation is given to verify the effectiveness of the proposed method in improving the flexibility of distribution network.