On the basis of the curve from Computer and Business Equipment Manufacturers Association(BEMA) ( CBEMA ) a quantitative evaluation index of load-loss caused by voltage sag, i.e., load-loss cost, is given. 基于CBEMA(ComputerandBusinessEquipmentManufacturersAssociation)曲线给出了一种电压暂降引起的失电损失定量评价指标&失电成本。