In a power grid with fluctuating voltage, the electric spring transfers it to the non-critical load in the target of guaranteeing that the electricity consumption varies with the power generation, thus alleviating the tricky problem rising from an unstable new energy generation effectively.However, it is bound to bring about new security risks to the power grid if a lot of non-critical load is applied for enhancing the voltage regulation of the electric spring.At present, there are few studies on the application configuration of electric spring.This paper first explains the basic principles of electric spring and the corresponding adjustment of the line voltage in a regional power grid.Secondly, a mathematical model of application configuration for electric spring is proposed.The model illustrates the quantitative relationship between the input of non-critical load and the reactive power from the electric spring.In addition, a configuration method of electric spring as to the minimum input of non-critical load is also proposed.Finally, the study results show that the minimum-proportion of non-critical load is obtained by this method and it forms an economical and rational configuration, the correctness and effectiveness of the configuration method is verified simultaneously.