A two-stage rolling optimization strategy for park-level integrated energy system considering multi-energy flexibility

Due to the advantages, such as being environment-friendly, the penetration of renewable energy has increased rapidly. However, the uncertainty and randomness of renewable energy source output severely impact economic dispatch, especially for those park-level integrated energy systems. To improve the economy of system operation and the accuracy of scheduling results, this paper presents a two-stage rolling dispatch strategy, in which a refined model of power flow, natural gas pipelines, and heat flow are established. The multi-energy flow model is linearized by the piecewise linearization method and second-order cone relaxation method. Moreover, a virtual energy storage model considering the thermal inertia in district heat systems and building enclosures is constructed. Further, to quantify the capacity of adjustable resources in park-level integrated energy systems, a multi-energy flexible source model is set up and integrated. Ultimately, to even out the prediction errors, a two-stage rolling dispatch is carried out, which corrects the results of day-ahead schedule plans. Based on the aforementioned works, case results demonstrate the effectiveness of the presented approach, both in renewable energy accommodation rate (with a promotion of 13.3%) and system operation economy (with a reduction of 14.55% in operation costs). It is recognized that the constructed models play important roles in improving the system flexibility and the presented operation strategy can effectively enhance the accuracy of the dispatch plans in real-time operation.