# 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
After obtaining the \(\mathrm{T_{m}}\) and \(\mathrm{V_{m}}\) values for all the municipalities in each month of the year, a classification was made for all the municipalities on the basis of their heat exchange potential. The classification was performed as follows:  
The temperature range was calculated as  
\[\mathrm{T_{m,max}}-\mathrm{T_{m,min}}=\mathrm{\Delta T_{max}}[^{\circ}\mathrm{C}] \tag{7}\]where  
* T\({}_{\text{m,max}}\) [\({}^{\circ}\)C] is the highest monthly average outdoor temperature recorded in Sicily for the corresponding month;
* T\({}_{\text{m,min}}\) [\({}^{\circ}\)C] is the lowest monthly average outdoor temperature recorded in Sicily for the corresponding month. The interval \(\Delta\)T\({}_{\text{max}}\) was then divided into three smaller intervals. The range of the intervals was selected to make the classification as effective as possible. Each interval is referred to as a \"temperature range (Range T\({}_{\text{i}}\))\". The wind speed range was calculated as  
\[\text{V}_{\text{m,max}}-\text{V}_{\text{m,min}}=\Delta\text{V}_{\text{max}} \Big{[}\frac{\text{m}}{\text{s}}\Big{]} \tag{8}\]  
where  
* V\({}_{\text{m,max}}\) [m/s] is the highest monthly average wind speed recorded in Sicily for the corresponding month;
* V\({}_{\text{m,min}}\) [m/s] is the lowest monthly average wind speed recorded in Sicily for the corresponding month. The \(\Delta\)V\({}_{\text{max}}\) interval was then divided into three smaller intervals. The range of the intervals was chosen to make the classification as effective as possible. Each interval is referred to as a \"wind speed range (Range V\({}_{\text{i}}\))\". All municipalities were classified into the corresponding temperature and wind speed ranges for each month of the year. Specifically, the temperature for a given municipality is indicated as follows:  
* \"Low T\" if it falls within Range T\({}_{\text{1}}\);
* \"Medium T\" if it falls within Range T\({}_{\text{2}}\);
* \"High T\" if it falls within Range T\({}_{\text{3}}\). Using the same criterion, the wind speed for the given municipality is indicated as follows:  
* \"Low Wind Speed\" (Low W.S.) if it falls within Range V\({}_{\text{1}}\);
* \"Medium Wind Speed\" (Medium W.S.) if it falls within Range V\({}_{\text{2}}\);
* \"High Wind Speed\" (High W.S.) if it falls within Range V\({}_{\text{3}}\). Some results are presented as an example (Table 4). In the phenomenon of the heat exchange between the conductor and the external environment, the wind speed impacting the overhead power line usually plays a more significant role than the average outdoor temperature [12]. For this reason, the nine possible combinations of temperature and wind speed have been classified, as reported in Table 5. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{4}{c}{**Data Referring to January**} \\ \hline
**Municipality** & **T\({}_{\text{m}}\)** [\({}^{\circ}\)**C]** & **V\({}_{\text{m}}\) [Km/h]** & **Temperature** & **Wind Speed** \\ \hline Acate & 9.67 & 21.63 & High T & High W.S. \\ Adrano & 6.94 & 8.27 & Low T & Low W.S. \\ Aci Castello & 10.64 & 9.58 & High T & Medium W.S. \\ Aci Catena & 9.75 & 9.58 & High T & Medium W.S. \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Classification of municipalities. Nine climatic classes were determined. Specifically, moving from one climatic class to the next reduces the conductor's propensity for heat exchange, as the average monthly wind speed gradually decreases and the average outdoor temperature increases. Once the methodology for classifying climatic classes had been established, several types of climatic analyses were conducted as follows:  
For each month of the year, the classification of Sicilian municipalities was assessed;  
Potential differences and similarities between Sicilian municipalities were observed.