A Multi-Rate Dynamic Energy Flow Analysis Method for Integrated Electricity-Gas-Heat System With Different Time-Scale

The integrated energy system (IES) combined electric power grid, natural gas network (NGN) and district heating network (DHN) is widely concerned because of its high efficiency and environmentally friendly. The accurate energy flow calculation of IES is the key to simulation analysis, operation optimization and control. This paper studies the dynamic energy flow of IES considering the different time-scale among the electric power, heat and gas networks. Firstly, a discretization method based on the delay characteristics of pipelines for DHN is proposed. By using this method, the selected temporal and spatial step sizes can be adaptively selected for thermal dynamic equation with application to different networks. Secondly, a discretization method for NGN is developed by considering the temporal step size of DHN as sampling period, so that the data interactions between two slow dynamic systems can be addressed in a same time series. Thirdly, a multi-rate energy flow calculation method with different temporal step sizes is presented for IES, which integrates the NGN and DHN considering different time-scale features to retain the state of IES as intact as possible. Simulation results illustrate the effectiveness of the proposed method, which provides dispatchers with more decision-making information.