Abstract: Traditional low frequency and low voltage load shedding devices adopt the open loop control in device outlet circuits,which is unable to identify the hidden failures cased by the state of shedding lines and doesn’t have the function of precise load shedding.Based on an analysis of low frequency and low voltage load shedding devices,the reasons for the infeasibility of precise load shedding and line state identification in the traditional transformer substation are explained.In the smart substation architecture,by accessing of generic object-oriented substation event（GOOSE）,the line state identification problem is solved.At the same time,with the application range of the GOOSE expanded and the power flow transmitted by GOOSE,a new method of precise load shedding is presented,which can meet the requirements of technology upgrading in low frequency and low voltage load shedding devices.