Node Voltage Sag Severity Evaluation Based on Improved Energy Index

According to the energy index that does not consider the influence of the sag type and the difference in the device's perceived sag level due to different equipment access phases, this paper proposes a method for evaluating the severity of node voltage sag based on improved energy index. Comprehensively consider factors such as sag amplitude, sag duration, sag type and general tolerance curve, and evaluate the severity of typical sensitive equipment at nodes under different sag types. The 14 sag events occurred in the busbar connected by a semiconductor user in an industrial park are selected for example verification, and the results show that the proposed method is reasonable and effective.