Engineering estimator for settled rectangular busbar and cable temperatures under RMS current. Deterministic thermal-network model, not a certified design approval.
| Item | Value | Unit | Note |
|---|
ρ(T) = ρ₂₀ · (1 + α · (T − 20)) — temperature-dependent resistivityR_seg = ρ(T) · dx / A — segment resistance (busbar or cable)g_conv = h · k · P · dx — convection conductance per busbar nodeg_ax = λ · A / dx — axial conduction conductancer_rad = ln(r_o/r_i) / (2π·K_ins) + 1/(h·k·2π·r_o) — cable radial thermal resistance per metreh_node = dx / r_rad — cable node conductance to ambientT_relaxed = ω·T_new + (1−ω)·T_old — successive relaxation update