Observability Analysis on State Estimation of Integrated Electricity-Gas System

State estimation plays a vital role in the operation monitoring and optimal dispatching of integrated electricity-gas system(IEGS). Before state estimation, observability analysis should be carried out for the system according to the existing measurement configuration to ensure the normal operation of state estimation. Because of the significant difference between the time constant of the electricity system and that of gas system, the differential-algebraic model is generally used to describe the coupling system of the two systems. Firstly, the finite difference method is used to differentiate the partial differential equation for describing the dynamic characteristics of natural gas. On this basis, the observability analysis is carried out for the IEGS, and the judgment basis and analytical steps are obtained for the observability analysis of the IEGS. Finally, the effectiveness of the proposed method is verified by a case study.