The New Methods for Calculating Voltage Sag Energy in Three-phase System

Voltage sag energy is an interesting single-event characteristic of voltage sag, to show the performance of sensitive equipment under voltage sag. According to the definition of voltage sag energy index, which proposed in IEEE Std. 1564-2014, the standard calculation method of voltage sag energy has not been available. This paper proposes six voltage sag energy calculation methods, with and without consideration of the two transition segments. It is considered three situations of calculation step size, including the sag duration, half-cycle step size and sampling point step size, which called full-process method, half-cycle method and sampling point method, respectively. The six methods are verified by 189 sets of measured voltage sag. The case studies verify the accuracy of the proposed methods, one of the methods is recommended as standard method.