Abstract:The calculation of branch line loss rate involves the power supply, sales, and grid topology structure, it’s complex and difficult to investigate the reasons for line loss alteration. This paper puts forward a method of investigating the reasons for line loss alteration under single and multiple influences by analyzing time-space factors which affect the calculation of line loss rate. Based on the historical data of line loss work, variable factors of line loss rate in time and space factors are studied according to the analysis of time factors and space factors. By quantitatively analyzing the relationship between variable factors and power consumption data of line loss rate, data models for power consumption changes and line loss rate changes corresponding to different factors are established. For the case of single line loss and multiple line loss changes, combined with the topology changes and line loss rate changes after the change, the electricity restoration calculation is carried out, and the abnormal change law and the restored change law are combined to achieve accurate judgment of the cause of the change.Finally, an example is given to demonstrate the effectiveness of the proposed method.