Site variation and prediction of power quality

We use EPRI´s distribution power quality project data to characterize and predict voltage sags and momentary interruptions based on site characteristics. The quality of sites is widely dispersed. Rural sites have many more sags and momentary interruptions than suburban and urban sites. The strongest indicators of voltage sags are: 1) circuit exposure, 2) lightning, and 3) a term with transformer impedance and number of feeders. We develop a linear model for predicting sags and another for predicting momentary interruptions based on site characteristics. We also compare transmission-level power quality to distribution power quality.