# Advanced Composite Materials: A Panacea for Improved Electricity Transmission
## 3 Further Challenges of Electricity Transmission Grids  
A number of challenges have been discovered to be militating against the maximum performance of transmission conductors, besides those itemized in the preceding sections. According to [39], overloading of grid, bush fire, lightning, extreme weather conditions, and short circuit are other major challenges that ravage transmission networks. Overloading of the transmission lines is a situation whereby a gigantic amount of current transverse through a conductor and provokes grid instability resulting in high load demand, especially during peak hours. This can cause power outage and even explosion of the line. This anomaly of excessive load demand has been escalated by rapid population growth and rise in economic development, all culminating into increased electricity demand [69]. Thus, the ampacity of existing transmission lines needs to be optimized. Hence, development of hybrid refractory nanomaterials can ameliorate the effect \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Properties/Types** & **ACSR** & **ACCR** & **ACCC** & **Al-CNTs-Nb** \\ \hline Thermal conductivity (W/mK) & 54 & 30 & 1.2 & 128 \\ \hline Maximum operating temperature (\({}^{\circ}\)C) & 95 & 180 & 125 & 400 \\ \hline Core density (g/cm\({}^{3}\)) & 8.05 & 3.00 & 1.94 & 2.72 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Comparative properties of transmission conductors [50]. Figure 6: Features of newly developed transmission conductor [50]. of overloading. This is because those materials can be stable at a very high temperature. Such materials should have high melting point, high thermal conductivity, low CTE, and low density. Nanomaterials of CNTs, BN, SiC, and TiC [14] are some of the materials that when dispersed on Al alloy will give it good thermal stability to withstand critical temperature rise. That which occurs when there is instantaneous current upsurge which may damage the transmission line if the material has low thermal conductivity and stability. Bushfire is another factor that inflics critical damage to transmission conductors. It occurs frequently during summer (dry) seasons in most countries. Excessive wind speed and dry wind cause volatile fire growth, resulting in power line failures in California, Australia, and other fire prone zones such as sub-Saharan Africa [70]. Bushfire occurrences may be caused by natural phenomena or human activities. Unlike human activities, causes by natural phenomena can hardly be controlled as they are ignited by adverse climate change. A report shows that flame temperatures can reach up to 1000 \({}^{\circ}\)C to 1200 \({}^{\circ}\)C, hence militating against the performance of conductors through causing damage to the tower structures, conductors, and connectors [71; 72]. Long exposure of conductors to bushfire can increase the temperature of transmission lines greatly, as shown in Figure 7. It causes the line temperature to rise from 5 \({}^{\circ}\)C to 15 \({}^{\circ}\)C higher than the normal operating temperature. This leads to premature ageing in transmission lines. Long exposure of conductors to bush flame aggravates mechanical deterioration of conductors. Thus, it reduces its load-carrying capacity, durability, and ampacity. To ameliorate this issue, refractory nanomaterials should be incorporated into the conductor material so that temperature of degradation will be increased. Moreover, human activities that lead to bushfires should be checkmated. Lightning is another natural disaster that attacks transmission lines. The strike can produce a momentary current that surpasses the thermal strength of the attacked line, resulting in the disturbance in the flow of current on the transmission grid. Peak stroke current ranging from 2 to 200 kA can be generated by lightning. For a 40 kA peak current strike of lightning, a temperature of 30,000 K and energy of 39,550 J/ohm are generated [73; 74].