Contingency Selection in the Context of Voltage Security Margin Determination

The present day power utilities highly stressed and operate very close to the stability limit. Because of this, the power utilities are confronting the issue in keeping up the required bus voltages. The power system which happened to be limited by transient (angle) stability have now moved toward becoming voltage stability constrained. Henceforth, the focal point of this paper is being on voltage stability and voltage security analysis. The voltage security can be assessed by performing AC load flow for different outages. Practically in a Power System, number of contingencies is large to the point that they can’t be investigated online by the AC load flow strategies. Subsequently the contingencies are, firstly, ranked according their relative degree of severity by implementing suitable selection algorithms. After this, the more severe contingencies are selected for full AC load flow analysis. This paper presents a functional link model based Artificial Neural Network (ANN) for the prediction of post-outage bus voltages. The contingencies are, then, ranked by implementing fuzzy logic approach by considering voltage deviation and voltage stability margin as well.