Abstract:In order to adapt to the wide application of HVDC transmission, the state estimation software of dispatching center urgently needs to be modified accordingly. At the same time, the emergence of UHVDC double valve group converter Pole also puts forward new requirements for DC modeling of state estimation. Aiming at the ±800kV UHVDC transmission, a DC transmission measurement model is proposed to meet the characteristics of the converter pole that contains double valve group. The model can also be compatible with single valve group operation mode. In order to ensure the smooth transition of the state estimation function, the alternating iterative method is used to realize the AC/DC hybrid state estimation by making minor modifications to the existing mature state estimation software. Some technical problems in the practical application of engineering are pointed out, including the design of the overall software flow, the consideration of converter loss, the correction of DC operation mode and the conversion of special measurement, and the corresponding solutions are proposed. The developed AC/DC hybrid state estimation software has been put into operation in the dispatching center of China Southern Power Grid. The practical application shows that its accuracy, efficiency and convergence meet the requirements of the actual project site.