## 6 Application of HTLS Conductors to Increase the Ampacity of Transmission Overhead Lines  
This section focuses on increasing the permissible load current achievable by replacing ACSR conductors with ACCC conductors. However, there are numerous possibilities to increase transmission capacities [19]:  
* Constructing new power lines;
* Upgrading existing power lines to higher voltages;
* Increasing the permissible load current;
* Structural modifications to overhead power lines;
* Installing compensating devices;
* Constructing new substations. Following the renewed utilization of standard STN EN 50341-2-23 [23] for ACCC conductors, the SLR is illustrated in Figure 8. Figures 9-12 illustrate the change in meteorological conditions, whereas other factors are maintained statically according to STN for SLR compared to alternative ACSR conductors. Just as with ACSR conductors, graphs for ACCC conductors confirm the electrical, thermal, and mechanical dependencies of this issue. A significant change is the pronounced increase in ampacity. For a clear and concise comparison between ACCC and ACSR conductors, a graphical representation depicting the temperature dependency on current loading is provided in Figure 13. Meteorological conditions were set according to STN standards for SLR. The maximum conductor temperature for ACSR conductors is 80 \({}^{\circ}\)C, whereas for ACCC, it is 200 \({}^{\circ}\)C. A comparison of values is described in Table 3.  
The conductor selection was based on achieving a similar diameter and weight compared to the ACSR conductors. The selection process involved comparing the diameter and weight of the conductors. The conductor diameter influences the wind and icing loads. As the diameter increases, there is a larger windage area or more ice accumulates on the conductor. With greater conductor weight, the loads on pylon structures increase. When selecting an equivalent conductor, it is necessary for these parameters to closely resemble those of the original conductors. The conductor parameters are provided in the following Table 4.  
Figure 8: Static ampacity \(I_{\text{max}}\) for the employed ACCC conductors. Figure 11: The relationship between the maximum allowable current value \(I_{\max}\) of different ACCC conductor types and the wind direction \(\theta\). Figure 10: The correlation between the maximum allowable current value \(I_{\max}\) of various ACCC conductor types and the wind speed \(V\). Figure 9: The correlation between the maximum allowable current value \(I_{\max}\) for various types of ACCC conductors and ambient temperature \(T_{\rm a}\). Figure 12: The correlation between the maximum allowable current value \(I_{\text{max}}\) of different types of ACCC conductors and the intensity of solar radiation \(I_{\text{T}}\). Figure 13: Effect of current variation \(I\) on the temperature \(T_{\text{s}}\) of ACSR and ACCC conductors under SLR conditions (numerical method). \begin{table}
\begin{tabular}{c c c c c} \hline
**ACSR Conductor** & \begin{tabular}{c} **Ampacity (A)** \\ **at \(T_{\text{s}}\) = 80 \({}^{\circ}\)C** \\ \end{tabular} & \begin{tabular}{c} **ACCC Conductor** \\ **at \(T_{\text{s}}\) = 80 \({}^{\circ}\)C** \\ \end{tabular} & \
\begin{tabular}{c} **Ampacity (A)** \\ **at \(T_{\text{s}}\) = 80 \({}^{\circ}\)C** \\ \end{tabular} &
\begin{tabular}{c} **Ampacity (A)** \\ **at \(T_{\text{s}}\) = 200 \({}^{\circ}\)C** \\ \end{tabular} \\ \hline
243-AL1/39-ST1A & 550.2 & LISBON & 641.7 & 1212.2 \\ \hline
352-AL1/59-ST1A & 703.2 & LUBBOCK & 814.1 & 1557.4 \\ \hline
382-AL1/49-ST1A & 733.9 & STOCKHOLM 2L & 815.9 & 1560.7 \\ \hline
429-AL1/56-ST1A & 789.8 & HAMBURG & 903.8 & 1738.7 \\ \hline
445-AL1/74-ST1A & 817.9 & ROME & 951.7 & 1836.4 \\ \hline \end{tabular}
\end{table} 
Table 3: The assessment of ampacity differences between ACSR and ACCC conductors at temperatures \(T_{\text{s}}\) of 80 and 200 \({}^{\circ}\)C (numerical method). The dynamic steady-state ampacity was applied to the transmission line V427 Rimavska Sobota--Moldava.