Observability and criticality analysis in state estimation using integer-preserving Gaussian elimination

摘要

This paper presents an efficient numerical method for observability and criticality analysis in power systemnstate estimation based on integer Gaussian elimination of integer coefficient matrices. Because all computationsnperformed are exact, no round-off error, numerical instability, or zero identification problems occur. Thenobservable islands are identified in a noniterative manner by performing back substitutions on the integerntriangular factors of the gain matrix. The additional measurements for placement are provided by a directnmethod, using the integer triangular factors of the Gram matrix associated with a reduced size Jacobian matrix.nThe critical measurements are identified by checking for diagonal entries of the integer residual sensitivitynmatrix. Implementation of the proposed method needs little additional effort, because it requires minornmodifications of sparse triangular factorization and forward/backward substitution algorithms common to statenestimators. The IEEE 14-bus system is used to illustrate the steps of the proposed algorithms. Test results for an10 343-bus system are provided to demonstrate the features of the proposed algorithms. Copyright © 2012nJohn Wiley & Sons, Ltd.