7. Appendix 1: Conductor bundle

Extra-high-voltage lines, above 300 kV, are almost exclusively equipped with bundles of several conductors per phase. This arrangement ensures that conductor surface fields remain within acceptable limits.

A bundle (figure 2 ) is characterized by the following quantities:

• n number of elementary conductors ;

• $\mathcal{R}$ radius of elementary conductors ;

• ${\mathcal{R}}_{\text{e}}$ equivalent beam radius ;

• ${}_{}$