Determine

a$)$ The critical disruptive voltage

$($a marks$)$

b$)$ The visual critucal voltage

$(6$ marks$)$

c$)$ The corona loss

$5$ marks

Uncler foul weather conditions for three $(3)$ phase line $160$ km long with conductor dvameter $1\mathrm{.}036$ cm and $2\mathrm{.}44$ m delta spacing. Aur temperature $26\mathrm{.}6$ corresponding to an approximate barometruc pressure of $73,15cm$ of mecury operating voltage at $110$ kV at $50$ Hz surface irregularity fuctor $0,85.$ Assume a value of $m_r=0,72.$ Dismuptive voltage under foul weather $=0,3$ faid weather value.