Optimal Operation Method for Electricity–Heat Integrated Energy System Considering Vulnerability Prevention

Abstract

The increasing integration of electricity and heating networks escalates the operation risk of an integrated energy system (IES). The vulnerable components in IES, which play an important role of aggravating the spread of IES failures, is one of the most important parts of risk control for IES operation. To ensure the operation security and stability of IES, an operation optimization method considering the vulnerability prevention for an electricity–heat IES is proposed in this paper. The method contains two main stages: vulnerability identification and optimal operation. First, the IES cascading failure space-time graph (CFSTG) is formed by simulating the cascading failure development stages in IES, which can effectively measure the impact of vulnerable branches on the cascading failure depth and breadth. Then, the vulnerable branches of IES are initially identified based on indices of node degree calculated according to CFSTG. In order to further screen and correct the initial identification results, a prevention–correction hybrid control strategy is proposed. On this basis, a day-ahead optimal operation bilevel model is established. Overall IES operating cost and static security are taken into account in the outer layer of the model to optimize electricity and heat output of each energy hub. After obtaining a multiobjective optimal energy flow distribution of IES, the inner layer of the model is developed to optimize the output of each unit in the energy hubs. Finally, an IES test system is utilized as an example to verify the effectiveness of the proposal method.