Substation Tools

A calculation toolset based on IEC 60865 for estimating mechanical forces in AC conductors during short circuits, using practical worst-case methods and accounting for real-world stresses in design.

OverviewShort-circuitThermal

Thermal effect on bare conductors

Check whether a bare conductor or busbar can handle a short-circuit without overheating: enter fault currents and duration (or a multi-step fault sequence), together with cross-section and temperature limits, and see whether the resulting current density stays below the allowed value.

Mode
Short-circuit episodes
Episode 1

Heat factor for d.c. component: 0.0560; heat factor for a.c. component: 0.8603 (SS-EN 60909-0)

Conductor

Note: ACSR aluminium area excludes steel core. Proximity effect is never included in this tool. (SS-EN 60865-1)

Results
Thermal equivalent short-circuit current, Ith
SS-EN IEC 60909-0
23.0 kA
Rated short-time withstand current density at reference duration, Sthr
SS-EN 60865-1
80.7 A/mm²
Allowable current density for actual fault duration, Sallow
SS-EN 60865-1
90.2 A/mm²
Thermal equivalent current density in conductor, Sth
SS-EN 60865-1
38.3 A/mm²
Thermal equivalent current density (effective), Sth,eff
Without a.c. skin effect (cross-section ≤ 600 mm²). SS-EN 60865-1; IEC 60287-1-1
38.3 A/mm²
Allowable current density (thermal limit), Sallow
SS-EN 60865-1
90.2 A/mm²
Meets thermal criterion, Sth,eff ≤ Sallow
SS-EN 60865-1
Pass