College of Energy and Electrical Engineering, Hohai University, Nanjing 211100, China

The development of integrated energy system plays a huge role in improving energy efficiency, reducing carbon emissions and increasing the permeability of renewable energy. Faced with the increasingly closely coupled integrated energy system of electricity-heat and electricity-gas interconnection, the existing energy management mode and scheduling means cannot give full play to their due advantages. Therefore, the realization of the integrated, efficient and accurate state estimation of the integrated energy system can provide reliable data support for the subsequent collaborative scheduling and safe operation. In view of this, this paper briefly summarizes the research on the state estimation of the integrated energy system in the background of carbon neutrality, and reviews the development history and difficulties of the theory of state estimation for the integrated energy system. The general idea of the research on the state estimation of the electricity-heat and electricity-gas integrated energy systems is analyzed from the three aspects of model, data and time scale. Finally, the future research directions of the integrated energy system state estimation are prospected.