This is the conductor steady-state temperature rise above ambient, as defined by Amendment 1 (2008) of the IEC 60853-2.

IEC 60853-2 Ed.1 used to define this to be the transient temperature rise of conductor above ambient temperature without correction for variation in conductor loss, and based on the conductor resistance at the end of the transient.

Symbol
$\Delta \theta_{\mathrm{t_{\mathrm{\infty}}}}$
Unit
K
Formulae
$- \theta_{\mathrm{c}} + \theta_{\mathrm{cmax}}$
Related
$\Delta \theta_{\mathrm{t}}$
$\theta_{\mathrm{c}}$
$\theta_{\mathrm{cmax}}$
Used in
$\Delta \theta_{\mathrm{a_{\mathrm{t}}}}$