Robust state estimation of electricity-gas-heat integrated energy system based on the bilinear transformations

A comprehensive energy system state estimation is of great significance to promote efficient, stable and reliable operation of the system. Based on coupling characteristics of electricity-gas-heat multi-energy flow and bilinear transformation method, this paper proposes a robust state estimation method suitable for integrated energy systems. First, the state estimation models of electricity, gas and heat energy subsystems and coupling components are constructed. Then, by introducing pseudo state variables and intermediate variables, the nonlinear state estimation process is divided into four stages. Among them, the first and third stages are solved by WLAV method and WLS method respectively, and the second and fourth stages are simple nonlinear transformation processes. Finally, the robust state estimation method is verified on a 40-node simulation example. The bilinear robust state estimation method proposed not only solves the difficulty of selecting initial values of heterogeneous networks and the problem of non-convergence of algorithms, but also can search and identify various types of bad data, and has high computational efficiency and good robustness.