College of Electrical Engineering and Information Technology, Sichuan University, Chengdu 610065, China

With steady liberalization of the electricity market, competition has been introduced into the sale of electricity. Providing quality customers with quality power supply service appears to be particularly important. The voltage sag insurance mechanism is exactly an effective way to improve users' satisfaction. Based on an analysis of the loss risk characteristics of voltage sag, the control type and financial type loss risk management modes are compared and discussed. Three voltage sag insurance mechanisms of financial risk management mode are set. By introducing the grey system theory and making comprehensive quantitative assessment of different insurance mechanisms through synthesizing the views of different entities, the most suitable and feasible insurance mechanism for the loss risk of voltage sag has been obtained. Finally, according to an empirical analysis of three high-tech customers in a high-tech park in China, the applicability and rationality of the method is proved.