## 3 Results and Discussion
### Operational Efficiency Evaluation of Power Grid Enterprises  
(1) Driving index evaluation  
We comprehensively evaluated eight driving indicators, and the results using SPSS software are shown in Table 4.  
Based on the processing results, we calculated the comprehensive evaluation model, as shown in the formula:  
\[F_{1}=0.373Z_{1}+0.322Z_{2}+0.358Z_{3}-0.362Z_{4}+0.378Z_{5}+0.333Z_{6}+0.333Z_{7 }+0.364Z_{8} \tag{16}\]  
where \(F_{1}\) is comprehensive score; and \(Z_{i}\) indicates the standard value of driving indicator \(i\). (2) Achievement index evaluation  
We also comprehensively evaluated eight achievement indicators, and the results using SPSS software are shown in Table 5.  
Based on the processing results, we calculated the comprehensive evaluation model shown in the formula:  
\[F_{2}=-0.321Z_{9}+0.291Z_{10}+0.031Z_{11}-0.112Z_{12}+0.3Z_{13}+0.294Z_{14}+0. 109Z_{15}-0.18Z_{16} \tag{17}\]  
where \(F_{2}\) is the comprehensive score; and \(Z_{i}\) indicates the standard value of achievement indicator \(i\). Based on the comprehensive evaluation model of the driving and achievement indexes, the index scores were calculated in combination with nearly six years of standard data. The trend chart is shown in Figure 5. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Component**} & \multicolumn{4}{c}{**Initial Eigenvalues**} & \multicolumn{4}{c}{**Extraction Sums of Squared Loadings**} \\ \cline{2-7}  & **Total** & **\% of Variance** & **Cumulative \%** & **Total** & **\% of Variance** & **Cumulative \%** \\ \hline
1 & 6.799 & 84.986 & 84.986 & 6.799 & 84.986 & 84.986 \\
2 & 0.914 & 11.419 & 96.405 & & & \\
3 & 0.162 & 2.020 & 98.425 & & & \\
4 & 0.116 & 1.451 & 99.875 & & & \\
5 & 0.010 & 0.125 & 100.000 & & & \\
6 & 3.01E-16 & 3.766E-15 & 100.000 & & & \\
7 & 1.72E-16 & 2.155E-15 & 100.000 & & & \\
8 & \(-\)2.71E-17 & \(-\)3.3394E-16 & 100.000 & & & \\ \hline \hline \end{tabular} Extraction Method: Principal Component Analysis.  
\end{table} 
Table 4: Processing results of the driving index. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Component**} & \multicolumn{4}{c}{**Initial Eigenvalues**} & \multicolumn{4}{c}{**Extraction Sums of Squared Loadings**} \\ \cline{2-7}  & **Total** & **\% of Variance** & **Cumulative \%** & **Total** & **\% of Variance** & **Cumulative \%** \\ \hline
1 & 4.091 & 51.139 & 51.139 & 4.091 & 51.139 & 51.139 \\
2 & 2.225 & 27.813 & 78.952 & 2.225 & 27.813 & 78.952 \\
3 & 1.006 & 12.579 & 91.530 & 1.006 & 12.579 & 91.530 \\
4 & 0.549 & 6.868 & 98.399 & & & \\
5 & 0.128 & 1.601 & 100.000 & & & \\
6 & 1.24E-16 & 1.560E-15 & 100.000 & & & \\
7 & \(-\)7.45E-17 & \(-\)9.323E-16 & 100.000 & & & \\
8 & \(-\)1.67E-16 & \(-\)2.094E-15 & 100.000 & & & \\ \hline \hline \end{tabular} Extraction Method: Principal Component Analysis.  
\end{table} 
Table 5: Processing results of the achievement index. From Figure 5, the driving index of operational performance had a rising trend. Although the achievement index as basically the same, there were some differences, especially shown by the different trends in 2011 and 2012. This difference showed that the driving index was not only the influencing factor of the achievement index, but the most important one. Thus, the index analysis could be replaced by the driving and achievement indexes, which could greatly reduce the amount of computation and improve efficiency. Combined with the general trend and efficiency evaluation of the driving and achievement indexes, it could release an early warning signal and make recommendations. ### Operational Efficiency Evaluation of Power Grid Enterprises  
(1) Comparison of operating efficiency over the years  
We used the driving index as the input index, and the achievement index as the output index. When considering the availability of the indicators, the output index was added, including the increased supply load of unit investment, the increased consumption of unit investment, and the transmission cost of unit quantity.