In EHV lines, bundled conductors are required for reducing:

Bundled conductor are those conductors which form from two or more stranded conductors, bundled together to get more current carrying capacity.

By using bundle conductors instead of the single conductor in the transmission line increases the GMR of the conductors.

So, inductance  reduces according to the following equation

\(\downarrow L = \frac{{{\mu _0}}}{{2\pi }}\ln \left( {\frac{{GMD}}{{ \uparrow GMR}}} \right)\) H/m/ph

Hence, the inductance per phase of the conductor decreases

So, capacitance  increases according to the following equation

\(\uparrow C = \frac{{2\pi {\varepsilon _0}{\varepsilon _r}}}{{\ln \left( {\frac{{GMD}}{{ \uparrow GMR}}} \right)}}\) F/m/ph

Hence, by using bundle conductors GMR is increased, so inductance L decrease and capacitance C increases.

Advantages of Bundled Conductors:

• Bundling of conductors leads to a reduction in line inductance.
• Bundling of conductors leads to increases in capacitance.
• An important advantage of bundled conductors is its ability to reduce corona discharge
• Reduction in the formation of corona discharge leads to less power loss and hence improved transmission efficiency of the line.
• Reduction in communication line interference.