Severity indicator of voltage sag for the existing voltage sag loss evaluation model is used for assessment. This kind of linear model is rather rough and such issues as diversity of the user’s electrical equipment and the difference of withstand voltage capability of different types of loads are not considered in the assessment. The concept of industrial process participation and a kind of economic loss assessment method of voltage sag based on a new fault probability model of load voltage sag are proposed. The scene of power grid suffering from voltage sag is constructed by Monte Carlo method. The voltage sage assessment is performed for the the insustrial users with multiple process flow and multiple different types of electrical equipments and corresponding control measures are formulated. For an industrial park

the configuration scheme of voltage compensation devices under two assessment models is solved respectively under the goal of considering both compensation effect and control cost

and the rationality of the economic loss assessment method of voltage sag in this paper is verified.