# Dynamic Thermal Rating and Development of Renewable Energy Zones in Sicily
## 4 Methodology
### Application of Dynamic Thermal Rating to Sicilian Transmission Grid
#### 4.2.1 Climatic Study of Sicilian Municipalities for Dynamic Thermal Rating
Looking at the overall classification made during the study, differences and similarities can be seen between all the regions of the island; during the winter months, most municipalities fall into the higher classes, while during the summer months, most municipalities fall into the lower classes. This is due to the fact that some areas of Sicily are characterized by more consistent wind patterns throughout the year, while other areas experience significant variations in wind speed, especially during the transition from winter to summer. It can be observed that the areas of Trapani, Ragusa, and Syracuse are usually characterized by high wind speeds throughout the year. In contrast, Enna and Messina are characterized by low wind speeds throughout the year. Palermo, on the other hand, has variable wind conditions throughout the year. Low wind speeds are observed in winter, gradually increasing to moderate wind speeds in summer. The Agrigento area also shows an increase in wind speeds from winter to summer, with moderate wind speeds in winter and high wind speeds in summer. The Catania area experiences medium to low wind speeds throughout the year, as does the Caltanissetta area (Table 6). From the above considerations, the potential of Dynamic Thermal Rating (DTR) is not the same in all areas of Sicily. The effectiveness of these devices increases with the wind speed hitting the electric conductor. It is, therefore, more advantageous to install a DTR on power lines in windier provinces such as Trapani, Syracuse, and Ragusa. It is also observed \begin{table}
\begin{tabular}{c c c} \hline \hline \multicolumn{4}{c}{**Windiness of the Provinces**} \\ \hline
**Province** & **January–June** & **July–December** \\ \hline Agrigento & Low T & High W.S. \\ Caltanissetta & Medium T & High W.S. \\ Catania & High T & High W.S. \\ Enna & Low T & Medium W.S. \\ Messina & Medium T & Medium W.S. \\ Palermo & High T & Medium W.S. \\ Ragusa & Low T & Low W.S. \\ Syracuse & Medium T & Low W.S. \\ Trapani & High T & Low W.S. \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Windiness of the provinces. \begin{table}
\begin{tabular}{c c c} \hline \hline \multicolumn{4}{c}{**Determination of Climatic Classes**} \\ \hline
**Class** & **Temperature** & **Wind Speed** \\ \hline
1 & Low T & High W.S. \\
2 & Medium T & High W.S. \\
3 & High T & High W.S. \\
4 & Low T & Medium W.S. \\
5 & Medium T & Medium W.S. \\
6 & High T & Medium W.S. \\
7 & Low T & Low W.S. \\
8 & Medium T & Low W.S. \\
9 & High T & Low W.S. \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Determination of climatic classes. that the effectiveness of the device depends on the identification of the hot spots of the power line. Identifying hot spots is a complex and challenging task [12]; it is safer to use DTR technology in areas where even at the hot spots, the wind speed is not too low. This reduces the likelihood of overheating in unidentified hot spots. In areas characterized by consistently low wind speeds (such as the provinces of Enna and Messina), the installation of DTR devices may not be advantageous from a purely climatic standpoint. This is for the following reasons:  
* The proposed increase in current capacity from DTR may be too small and not beneficial enough;
* The hot spots in these areas may be critical enough to make the use of DTR unsafe. In this case, the suggested solution is the re-conducting of the electrical line. If Dynamic Thermal Rating is insufficient, another solution to address the increase in power flows is to increase the ampacity of electrical transmission lines through \"re-conducting\" [19]. This involves replacing old, worn-out lines with new conductors that can operate at higher temperatures while still maintaining the required minimum ground clearance, thus reducing the space occupied by infrastructure. The new-generation conductors are HTLS (High-Temperature Low-Sag) conductors, which have almost identical cross-sections to conventional conductors but improve the transport capacity, efficiency, and reliability of the electrical grid.