Research on Evaluation Method of Voltage Sag Severity Based on Extenics

Because the current description methods cannot fully describe the voltage sag tolerance characteristics of nodes, and considering the impact of voltage sag characteristic quantities on the accuracy of voltage sag severity assessment results, a evaluation method of node voltage sag severity based on extenics is proposed. Considering the four voltage sag characteristics quantities of magnitude, duration, starting point and phase jump, the extension evaluation model of voltage sag severity is established, and the single event is evaluated. Combining with the evaluation results of all voltage sag events, a judgment model of node voltage sag severity level is proposed to calculate the node comprehensive severity level. The validity of the node voltage sag severity assessment method based on extenics is verified by an example analysis.