A novel methodology for determining the voltage sag Impact Factor

Abstract

This paper proposes a methodology for determining a site index that considers the equipment sensitivity to voltage sags, the variation in their level of sensitivity, and the influence of unbalanced sags on three-phase loads. Some single-event characteristics are easily applicable when obtaining site indexes, however, they are overly generic to consider all the above-mentioned aspects, and the more specific indices present the inconvenience of calculation parameters that are dependent on the equipment type, which makes them more adequate to quantify the impact of voltage sags on certain loads rather than to evaluate the sites’ performance. In this context, the proposed methodology aims to obtain a single set of calculation parameters that is applicable to all cases, allowing large-scale assessments. For this purpose, a statistical approach is adopted, considering the correlation between the index and the number of equipment trips, in order to define the adjustment most correlated with the sensitivity level of different types of loads. The Impact Factor is used as a basis in determining the desired index. A case study illustrates the application of the proposed methodology, showing how these aspects can be addressed from a better definition of the Impact Factor.