Contingency studies in interconnected electric power systems are performed to assess the capability of a system to withstand disturbances caused by equipment outages and other factors, and are relevant to the area of power system security. Due to the large size and complexity of modern power systems, accurate techniques for measuring the effect of line contingencies are often time consuming and impose a heavy computational burden. Thus, ranking methods are used to define a subset of the most severe contingencies to be studied in full detail. Contingencies are classified into voltage contingencies and power contingencies; the term voltage contingency refers to cases of bus voltage magnitude out of range, and the term power contingency refers to the case of line power flow out of range (overloads). The purpose of this research is to examine the singular value decomposition of a voltage sensitivity matrix derived from the Jacobian matrix of the Newton-Raphson power flow equation and its relationship to voltage contingency ranking. Possible ways of using the singular values in a bus voltage ranking performance index will also be studied. Additionally, methods of assessing the accuracy of contingency ranking performance indices will be considered. Proposed enhancements to these strategies and recommendations for further research will be discussed.

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