## 2 Fault Type and Fault Feature Information of the Protection System
### Fault Feature Information Set of the Protection System  
According to the fault feature information in Table 3, the fault feature information set is established to provide data support for the subsequent fault diagnosis of the protection system of an intelligent substation. The integrated alarm information set \(A_{i}\) of the protection system of an intelligent substation in the \(i\)-th fault event is established as shown in Formula (2):  
\[A_{i}=\{a_{1},a_{2},a_{3},\ldots,a_{11}\} \tag{2}\]  
\(a_{1}\)-\(a_{11}\) in the above formula are the \(11\) kinds of fault feature information contained in the integrated alarm information in Table 3. When the monitoring host receives the alarm information, the element at the corresponding position is set to \(1\), otherwise it is set to \(0\). The link information of the GOOSE and SV set \(I_{i}\) of the protection system of an intelligent substation in the \(i\)-th fault event is established as shown in Formula (3):  
\[I_{i}=\{i_{1},i_{2},i_{3},\ldots,i_{6}\} \tag{3}\]  
\(i_{1}\)-\(i_{6}\) in the above formula are the 6 kinds of fault feature information contained in the link information of GOOSE and SV in Table 3. When the secondary monitoring system receives the alarm information, the element at the corresponding position is set to 1, otherwise it is set to 0. \begin{table}
\begin{tabular}{c c} \hline \hline
**Type of Fault Feature Information** & **Fault Feature Information** \\ \hline \multirow{7}{*}{Integrated alarm information} & Protection locking, Abnormal alarm of merging unit, Abnormal alarm of intelligent terminal, Abnormal alarm of protection device, SV total alarm, GOOSE total alarm, SV alarm of merging unit, SV alarm of protection device, GOOSE alarm of merging unit, GOOSE alarm of protection device, GOOSE alarm of intelligent terminal \\ \hline \multirow{7}{*}{Link information of GOOSE and SV} & GOOSE interruption of merging unit, GOOSE interruption of protection device, GOOSE interruption of intelligent terminal, SV interruption of protection device, SV interruption of measurement and control device \\ \hline \multirow{7}{*}{Sampling anomaly of merging unit, Synchronization anomaly of merging unit, Board card configuration error, Merging unit memory checking error, Incorrect configuration of send text for merge unit, B01 HTM error of merging unit, BO1 report, BO3 Stall error of merging unit, BO3 sampling plate anomaly of merging unit, Sampling of BO3 dual AD in merging unit is inconsistent, GOOSE-A network storm of merging unit, BO2 sampling power drop of merging unit, Intelligent terminal, Memory-checking error, B09 optocoupler power loss of intelligent terminal, BO1\_A network link N of intelligent terminal disconnected, BO1\_GOOSE-A network storm alarm of intelligent terminal, BO1\_GOOSE configuration error of intelligent terminal, BO2\_A network link N of intelligent terminal disconnected, B01 synchronous anomaly alarm of intelligent terminal, B01 HTM error of intelligent terminal, BO1 report BO2 stall error of intelligent terminal, BO3 sampling power supply anomaly of intelligent terminal, Channel differential exit, Longitudinal channel abnormal, Protection device parameter error, Abnormal timing of protection device, In/out communication interruption of protection device, Abnormal synchronous voltage, CPU X exception, Memory self-check error, 4–8 Bus MU frame loss, 4–8 Bus check error \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Protect system fault feature information.