A decoupled second order state estimator for AC-DC power systems

This paper presents a new framework for decoupled state estimation of AC-DC power systems. Decoupling is not done by zeroing the off-diagonal submatrices of the Jacobian and gain matrices but as a two-step procedure. The mathematical model involves both the first and second order derivatives of the performance equations. Only diagonal blocks of the gain matrix are required to be factorized, and they remain constant in the iterative solution scheme. Their size and structure are similar to those in the fast decoupled state estimator which is based on the linearised version of the Taylor series equations. Test results are presented,compared and discussed. The proposed method performs satisfactorily and its computational requirements are comparable with those of the fast decoupled state estimator