# A Method of Discriminating Between Power Swings and Faults Based on Principal Component Analysis
## 4 Simulation Tests
### Comparison and Discussion
Considering the effect of measurement noise, the method in [27] can more easily misjudge the power swing as a fault. Tables 9-11 show the performance of the three methods in detecting three-phase shorting faults during power swings. Comparing Tables 9 and 10, it can be seen that both the proposed method and the traditional method can detect faults reliably, no matter where the fault occurs on the line, and are less affected by measurement noise. At the same time, the proposed method has an advantage in terms of response speed. Comparing \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \(f_{\text{ps}}\) (Hz) & **Distance (km)** & \(\delta\) & **SNR (dB)** & \(k\) & **R** & **T (ms)** \\ \hline \multirow{8}{*}{7.00} & 10 & 50\({}^{\circ}\) & - & 0.29 & \(\surd\) & 29.50 \\  & 150 & 50\({}^{\circ}\) & - & 0.27 & \(\surd\) & 31.75 \\  & 290 & 50\({}^{\circ}\) & - & 0.29 & \(\surd\) & 32.00 \\  & 150 & 120\({}^{\circ}\) & - & 0.29 & \(\surd\) & 23.50 \\  & 150 & 180\({}^{\circ}\) & - & 0.12 & \(\surd\) & 12.75 \\  & 150 & 220\({}^{\circ}\) & - & 0.21 & \(\surd\) & 33.00 \\  & 150 & 120\({}^{\circ}\) & 50 & 0.29 & \(\surd\) & 23.50 \\  & 150 & 120\({}^{\circ}\) & 40 & 0.29 & \(\surd\) & 23.50 \\  & 150 & 120\({}^{\circ}\) & 30 & 0.29 & \(\surd\) & 23.50 \\ \hline \multirow{8}{*}{0.40} & 10 & 50\({}^{\circ}\) & - & 0.28 & \(\surd\) & 30.25 \\  & 150 & 50\({}^{\circ}\) & - & 0.27 & \(\surd\) & 32.50 \\  & 290 & 50\({}^{\circ}\) & - & 0.29 & \(\surd\) & 32.50 \\  & 150 & 120\({}^{\circ}\) & - & 0.28 & \(\surd\) & 36.00 \\  & 150 & 180\({}^{\circ}\) & - & 0.27 & \(\surd\) & 8.50 \\  & 150 & 220\({}^{\circ}\) & - & 0.29 & \(\surd\) & 35.75 \\  & 150 & 120\({}^{\circ}\) & 50 & 0.28 & \(\surd\) & 35.50 \\  & 150 & 120\({}^{\circ}\) & 40 & 0.24 & \(\surd\) & 35.00 \\  & 150 & 120\({}^{\circ}\) & 30 & 0.27 & \(\surd\) & 36.25 \\ \hline \hline \end{tabular}
\end{table} 
Table 11: Test results for PSD of traditional method in [27]. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \(f_{\text{ps}}\) (Hz) & **Distance (km)** & \(\delta\) & **SNR (dB)** & **DI** & **R** & **T (ms)** \\ \hline \multirow{8}{*}{7.00} & 10 & 50\({}^{\circ}\) & - & 0.92 & \(\surd\) & 0.50 \\  & 150 & 50\({}^{\circ}\) & - & 0.12 & \(\surd\) & 1.25 \\  & 290 & 50\({}^{\circ}\) & - & 0.33 & \(\surd\) & 1.25 \\  & 150 & 120\({}^{\circ}\) & - & - & \(\times\) & - \\  & 150 & 180\({}^{\circ}\) & - & 0.04 & \(\surd\) & 0.75 \\  & 150 & 220\({}^{\circ}\) & - & 0.09 & \(\surd\) & 0.75 \\  & 150 & 120\({}^{\circ}\) & 50 & - & \(\times\) & - \\  & 150 & 120\({}^{\circ}\) & 40 & - & \(\times\) & - \\  & 150 & 120\({}^{\circ}\) & 30 & - & \(\times\) & - \\ \hline \multirow{8}{*}{0.40} & 10 & 50\({}^{\circ}\) & - & 1.33 & \(\surd\) & 0.75 \\  & 150 & 50\({}^{\circ}\) & - & 0.19 & \(\surd\) & 1.00 \\  & 290 & 50\({}^{\circ}\) & - & 0.49 & \(\surd\) & 1.50 \\  & 150 & 120\({}^{\circ}\) & - & 0.33 & \(\surd\) & 1.00 \\  & 150 & 180\({}^{\circ}\) & - & - & \(\times\) & - \\  & 150 & 220\({}^{\circ}\) & - & 0.02 & \(\surd\) & 1.00 \\  & 150 & 120\({}^{\circ}\) & 50 & - & \(\times\) & - \\  & 150 & 120\({}^{\circ}\) & 40 & - & \(\times\) & - \\  & 150 & 120\({}^{\circ}\) & 30 & - & \(\times\) & - \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Test results for PSD of traditional method in [5].