## 4 Application Example
### Economic Effects of Improving the Sustainability of the Transformation House  
The economic costs derived from the operation of each transformer are obtained by multiplying the value of its total energy losses (in the copper and in the core), for each hourly period (P1, P2, P3, P4, P5 and P6) and type of day (A, B, B1, C and D), according to Table 3, by the energy prices in each hourly period (Table 1). The effects of the increase in electricity prices from January 2020 to January 2022 have been considered in the study. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Transformer** & **Working Days (251)** & **Holidays (114)** & **Total (365)** \\ \hline Ormazabal 1600 kVA (\({}^{1}\)) & 4957.84 & 2165.76 & 7123.60 \\ \hline Ormazabal 1600 kVA (\({}^{2}\)) & 4696.42 & 1729.15 & 6425.57 \\ \hline Efficient & & & \\
1600 kVA (\({}^{3}\)) & 2218.60 & 722.56 & 2941.16 \\ \hline Efficient & & & \\
1000 kVA (\({}^{3}\)) & 2061.59 & 473.87 & 2535.46 \\ \hline Efficient & & & \\
800 kVA (\({}^{3}\)) & 2151.27 & 406.60 & 2557.87 \\ \hline Efficient & & & \\
630 kVA (\({}^{3}\)) & 2262.87 & 322.52 & 2585.39 \\ \hline \hline \end{tabular}
\end{table} 
Table 13: Annual carbon dioxide emissions, in kg/year: (\({}^{1}\)) current operation; (\({}^{2}\)) optimizing operation of capacitors; and (\({}^{3}\)) using efficient transformers and optimizing the operation of capacitor banks. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{2}{c}{**Total Copper Losses**} & \multicolumn{2}{c}{**Total Losses (kwh/year)**} \\ \cline{2-5}
**Transformer** & \multicolumn{2}{c}{**Working Days (251)**} & **Holidays (114)** & **Working Days (251)** & **Holidays (114)** & **Total (365)** \\ \hline Ormazabal 1600 kVA (\({}^{1}\)) & 4909.54 & 1872.98 & 20,571.94 & 8986.57 & 29,558.52 \\ \hline Ormazabal 1600 kVA (\({}^{2}\)) & 3824.84 & 61.31 & 19,487.24 & 7174.91 & 26,662.15 \\ \hline Efficient 1600 kVA (\({}^{3}\)) & 2699.89 & 43.28 & 9205.81 & 2998.16 & 12,203.96 \\ \hline Efficient 1000 kVA (\({}^{3}\)) & 4379.68 & 70.20 & 8554.32 & 1966.25 & 10,520.57 \\ \hline Efficient 800 kVA (\({}^{3}\)) & 5402.42 & 86.59 & 8926.46 & 1687.16 & 10,613.62 \\ \hline Efficient 630 kVA (\({}^{3}\)) & 6678.71 & 107.05 & 9389.51 & 1338.25 & 10,727.76 \\ \hline \hline \end{tabular}
\end{table} 
Table 12: Annual copper losses (\(W_{c}^{(1)}\), \(W_{c}^{(2)}\) and \(W_{c}^{(3)}\)) and total losses (copper + core losses): (\({}^{1}\)) current operation of capacitors; (\({}^{2}\)) by optimizing the operation of capacitors; and (\({}^{3}\)) using efficient transformers and optimizing the operation of capacitor banks. The economic costs corresponding to the total losses of the inefficient transformer of 1600 kVA, without optimizing the operation of the capacitor bank \(Q_{c2}\), are indicated in the fourth column of Table 14. Likewise, the economic costs due to the total energy losses of the inefficient transformer of 1600 kVA and of the efficient replacement transformer of 1000 kVA, when the operation of the capacitor bank \(Q_{c2}\) has been optimized, are indicated in the sixth and eighth columns, respectively, of Table 14.  
The third, fifth and seventh columns of Table 14 indicate the energy lost daily, in kWh, for each transformer at peak hours (P1-A, P2-B, P3-B1, P4-C), at low hours (P2-A, P3-B, P4-B1, P5-C), off-peak hours on working days (P6(4)) and 24 h a day on holidays (P6(5)), with the times indicated in Table 3 for each type of day of the year (A, B, B1, C and D). The daily values of the energy losses in the transformer have been obtained by adding the consumption at peak hours (9-14 h and 18-22 h), flat (8-9 h, 14-18 h and 22-24 h) and valley (0-8 h, on working days and 24 h on holidays). These hours are the same throughout the year, but the price of energy in each of these hours has a different value, depending on the type of day of the year (Table 1).