## 4 Discussion
### Methodology for Determination of Equatorial Efficiency
Since the analysis was conducted for four inverters (with different technology), a generalized relationship for \(\eta_{EQUA}\) needs to be determined. Because the weightage for each inverter shows very small variations compared to the other ones, it is sufficient to take a simple average of the individual weightage for every inverter at every level of operation. As shown in Table 9, the average weightage was 0.0875, 0.1125, 0.0800, 0.1250, 0.4400, and 0.1550, respectively. To simplify the formula, the numbers were rounded to two decimal places. Thus, the suggested Equatorial Efficiency (\(\eta_{EQUA}\)) formula can be written as  
\[\eta_{EQUA}=0.09\times\eta_{5\%}+0.11\times\eta_{10\%}+0.08\times\eta_{20 \%}+0.13\times\eta_{30\%}+0.44\times\eta_{50\%}+0.15\times\eta_{100\%} \tag{11}\]  
With the adoption of the new \(\eta_{EQUA}\), Table 10 shows the summary of the difference in the weighted efficiency for the four inverters. As can be observed, in all cases, the \(\eta_{EQUA}\) is less than the \(\eta_{EURO}\) from the datasheet. The \(\eta_{EQUA}\) is also lower than the recalculated \(\eta_{EURO}\), i.e., \(\eta_{EURO\_real}\). The differences are in the range from 0.5% to 3.99%. These findings imply that if \(\eta_{EURO}\) is used to compute the \(E_{sys}\), it will lead to incorrectly high energy production estimation. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Level of Operation** & \multicolumn{2}{c}{**Range of**} & \multirow{2}{*}{**Weightage (WT) (-)**} & \multirow{2}{*}{**\(\eta_{meas\_ave}\) (\%)**} & \multirow{2}{*}{**WT \(\times\eta_{meas\_ave}\)**} \\ \cline{2-2}
**(LO) (\%)** & & & & \\ \cline{1-1}
5 & 0–7.5 & 0.07 & 85.41 & 5.9787 \\
10 & \(>\)7.5–15 & 0.17 & 90.69 & 15.4173 \\
20 & \(>\)15–25 & 0.06 & 95.23 & 5.7138 \\
30 & \(>\)25–40 & 0.10 & 95.30 & 9.5300 \\
50 & \(>\)40–75 & 0.43 & 95.12 & 40.9016 \\
100 & \(>\)75 & 0.17 & 94.94 & 16.1398 \\ \(\eta_{EQUA}\) (\%) & & & 93.6812 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Weighted efficiency for the K4200 TL inverter when \(G=Gi\) and \(T=25\)\({}^{\circ}\)C with individual weightage. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Level of Operation** & \multicolumn{2}{c}{**Range of**} & \multirow{2}{*}{**Weightage (WT) (-)**} & \multirow{2}{*}{**\(\eta_{meas\_ave}\) (\%)**} & \multirow{2}{*}{**WT \(\times\eta_{meas\_ave}\)**} \\ \cline{2-2}
**(LO) (\%)** & & & & \\ \cline{1-1}
5 & 0–7.5 & 0.11 & 86.56 & 9.5216 \\
10 & \(>\)7.5–15 & 0.11 & 94.52 & 10.3972 \\
20 & \(>\)15–25 & 0.07 & 95.32 & 6.6724 \\
30 & \(>\)25–40 & 0.12 & 95.24 & 11.4288 \\
50 & \(>\)40–75 & 0.43 & 94.92 & 40.8156 \\
100 & \(>\)75 & 0.16 & 94.67 & 15.1472 \\ \(\eta_{EQUA}\) (\%) & & & 93.9828 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Weighted efficiency for K7900 TL inverter when \(G=Gi\) and \(T=25\)\({}^{\circ}\)C with individual weightage. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Level of Operation** & \multicolumn{2}{c}{**Range of**} & \multirow{2}{*}{**Weightage (WT) (-)**} & \multirow{2}{*}{**\(\eta_{meas\_ave}\) (\%)**} & \multirow{2}{*}{**WT \(\times\eta_{meas\_ave}\)**} \\ \cline{2-2}
**(LO) (\%)** & & & & & \\ \cline{1-1}
5 & 0.08 & 0.09 & 0.07 & 0.11 & 0.0875 & 0.09 \\
10 & 0.09 & 0.08 & 0.17 & 0.11 & 0.1125 & 0.11 \\
20 & 0.10 & 0.09 & 0.06 & 0.07 & 0.0800 & 0.08 \\
30 & 0.15 & 0.13 & 0.10 & 0.12 & 0.1250 & 0.13 \\
50 & 0.47 & 0.43 & 0.43 & 0.43 & 0.4400 & 0.44 \\
100 & 0.11 & 0.18 & 0.17 & 0.16 & 0.1550 & 0.15