Abstract:
High penetration rate of renewable energy is inevitable in the future grid, in which the volatility and randomness characteristics may cause flexibility insufficient to system operation of the distribution network. An optimal scheduling model of technical virtual power plant that takes into account the flexibility and economy of the distribution network is proposed in this paper, in which the internal network operation constraints and security constraints are considered. Firstly, an index of flexibility is established to ensure that the system has sufficient flexibility margins for each period of operation in the electricity market environment. The pricebased demand response is established through a stepwise elasticity method, by which the users are guided to responded to the changes of wind and photovoltaic power output, and electricity market prices. Scenario analysis method is used to describe the uncertainty of wind power and photovoltaics, and the extreme scenario is optimized to ensure flexibility of the system. Then, the non-convex nonlinear conditions in the model are relaxed into a mixed-integer second-order cone programming problem based on the second-order cone convex optimization theory and Big-M approach so as to get the solutions more effectively. Finally, the validity and rationality of the model are verified based on the simulation results.