Use of base case Jacobians in power flow solution under topological changes

Fast decoupled Newton-Raphson method is the most widely used algorithm for load flow analysis needed in on-line assessment of the steady state security of a power system. To repeat the load flow analysis corresponding to the topological changes arising from a contingency or a remedial action, usually the base case Jacobian matrices are reinverted through inverse matrix modification lemma or partial matrix refactorisation technique. The present paper proposes the use of base case Jacobians without reinversion or refactorisation and reforming only the right side vector in each iteration. A comparative performance study between the proposed and the partial refactorisation techniques regarding their on-line CPU time requirements and solution accuracy has been made by conducting extensive simulation tests on a real power system for wider spectrum of practical cases involving topological changes