Abstract: Errors lie in the grid parameters can reduce the reliability of advanced applications in the Energy Management System(EMS). Thus it is the basis for effective analysis and control on the grid to ensure the correctness of grid component parameters. For this purpose, this paper has proposed a parameter identification and correction scheme on the basis of Lagrangian multiplier method. Firstly, we have observed that local parameter errors can cause the Lagrangian multipliers and the measurement residuals to increase locally. And we define the suspicious measurement and parameter decision functions respectively. Furthermore, comprehensive suspicious index of each parameter is introduced based on the above two type of decision functions by which we can generate a so-called suspicious parameter set. Finally, for the suspicious parameters in the suspicious parameter set, a suspicious parameter modification scheme with varied step is proposed. The method can realize the dynamic correction of the parameter errors, and has high correction precision and no convergence problem.

Key words: power system, state estimation, Lagrangian multiplier, suspicious function, varied-step correction