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Transient temperature rise conductor

This is the transient temperature rise of conductor above ambient temperature.

After calculating separately the two partial transients and the conductor to cable surface attainment factor the total transient rise above ambient temperature is obtained

Symbol
$\delta \theta_{c,t}$
Unit
K
Formulas
$\delta \theta_{c,t,o}$cables in air
$\delta \theta_{c,t,o}+\alpha_t \delta \theta_{e,t}+\alpha_t v_4 \Delta \theta_{p,t}$buried cables emergency rating
$\delta \theta_{c,t,o}+\Delta \theta_{d,t}+\alpha_t \delta \theta_{e,t}+\alpha_t v_4 \Delta \theta_{p,t}$buried cables transient
Related
$\alpha_t$
Conductor to surface attainment factor
$\delta \theta_{c,\infty}$
Steady-state temperature rise conductor [K]
$\delta \theta_{c,t,o}$
Transient temperature rise conductor by ohmic losses [K]
$\Delta \theta_{d,t}$
Transient temperature rise by dielectric losses [K]
$\delta \theta_{e,t}$
Transient temperature rise outer surface [K]
$\Delta \theta_{p,t}$
Transient temperature rise outer surface by other buried objects [K]
$v_4$
Ratio thermal resistivity dry/moist soil
Used in
$\delta \theta_{\alpha,t}$
Corrected transient temperature rise conductor [K]
$I_{c,2}$
Emergency overload current [A]
$\theta_{ar}$
Temperature armour [°C]
$\theta_{c,t}$
Transient temperature conductor [K]
$\theta_e$
External temperature object [°C]
$\theta_s$
Temperature screen/sheath [°C]