Abstract: To address the issue that existing assessment methods fail to consider the differences and uncertainties in the tolerance capabilities of sensitive equipment within industrial parks, this paper proposes a novel interval assessment method for voltage sag severity by integrating affine arithmetic and game theory-combined weighting. The affine algorithm is introduced to handle the uncertainty of equipment tolerance parameters, aiming to overcome the “interval explosion” problem inherent in traditional interval operations, thereby quantifying the impact of voltage sags more precisely. First, the propagation mechanism of voltage sags is analyzed, and a sag tolerance factor model based on equipment tolerance characteristics is constructed. Second, interval number theory is introduced to characterize the uncertainty in equipment tolerance parameters. Affine arithmetic is employed to handle this uncertainty, mitigate the excessive conservatism of conventional interval operations, thereby ultimately establishing an interval assessment model for the comprehensive severity of voltage sags on the user side. Finally, the IEEE 30-bus system is used as a case study to simulate voltage sag propagation and equipment responses under different fault scenarios. Simulation results indicate that compared to traditional interval algorithms, the average width of the assessment intervals obtained by the proposed method is reduced by over 80%. This effectively suppresses the "interval explosion" phenomenon, significantly lowers the conservatism of the assessment results, and thus more accurately characterizes the uncertainty of equipment tolerance characteristics. This provides a reliable scientific basis for power quality management and sensitive equipment selection in industrial parks.

Key words: voltage sag, severity assessment, sensitive equipment, tolerance characteristics, affine arithmetic, interval assessment