The intelligent electronic device（IED）modeling method in IEC 61850 protocol is described. Then the IED modeling method is applied to the intelligent terminal device instances

the IED modeling methodology and process are introduced in terms of function definition

function decomposition

and equipment object model

and the effects achieved after modeling are given. This study may provide a reference for building other IED models.And the proposed IED modeling method can achieve good interoperability between intelligent electronic devices from different manufacturers

realized seamless system integration

avoid duplicate investment

and reduce maintenance costs of the system.