Incorporation of Linearized Sensitivities in the Ward Method of Equivalencing

In system planning, engineers specify an area of interest within an interconnected power network. Utilities often use the Ward equivalent to reduce external areas to a minimal representation. However, the industry has reported poor results using Ward equivalents in approximate contingency analysis. This paper proposes a simple method of updating the Ward equivalent using linearized sensitivities. The technique is computationally economical and is more accurate than the standard Ward equivalent in studying system changes.