The fault diagnosis information is classified and the extended SCL is applied to describe the primary component topology and protection configuration. The IEC 61850 standard is used to transmit protection operating information and breaker tripping information. All the relevant information obtained is modeled in a unified manner according to the IEC 61970 CIM and IEC 61850 hierarchy model， and is extended to fit fault diagnosis characteristics. The modeling method has solved the problem of attaining fault diagnosis information integrity and standardization， making the fault diagnosis system real practical.