Research On Distributed State Estimation Of Integrated Energy System

Integrated Energy System(IES)is regarded as one of the important means to improve the overall energy utilization efficiency,strengthen the absorption capacity of renewable energy,and achieve the "dual carbon goal".State Estimation(SE)of integrated energy systems can provide accurate and reliable mature data for integrated energy systems,and is the cornerstone of safe,economic,and stable operation of integrated energy systems.Currently,the research on centralized state estimation methods in the field of integrated energy system state estimation is relatively mature.However,due to the different management entities of each subsystem constituting the integrated energy system,there are industry barriers such as operational information privacy and operational differences,which limits the application scope of centralized state estimation methods.At the same time,existing distributed state estimation methods have poor robustness,making it difficult to provide accurate estimates when bad data occurs.Therefore,this paper proposes distributed robust state estimation methods suitable for steady-state and transient operation of integrated energy systems.The main work is as follows:(1)A distributed robust SE method based on Weighted Least Absolute Value(WLAV)is proposed for the Integrated Electricity-Heat System(IEHS).The proposed method has the following characteristics:1)During state estimation,the subsystems of IES only need to interact with the operational data of the coupled components,which ensursa the security and privacy of the operational data;2)This method has good robustness and can obtain accurate estimates when measurement data obtains strongly correlated bad data.(2)A distributed robust SE method based on Second-Order Cone(SOC)is proposed for the Integrated Electricity-Heat System.In order to compensate for the loss of measurement redundancy caused by linear transformation,the cone-relaxation technique is used to construct a convex optimization model to ensure the global optimal solution.It is proved that this method can not only obtain more accurate state variable estimation value of power system,but also has better robustness.(3)A distributed robust SE method based on robust Kalman filter is proposed for the Integrated Electricity-Gas System.The proposed method has the following characteristics:1)Considering the dynamic characteristics of gas system,the linear state transition equation is constructed based on the partial differential equation;2)The linear interpolation method is used to "align" the measurement of two systems with different sampling periods to ensure the observability;3)The robustness dynamic SE method adopts robust Unscented Kalman filter method in power system and approximate least-multiplicative robust Kalman filter method in gas system.Examples show that the method can obtain accurate state variables estimates in both normal and bad data measurements.