Electrical & Drives · Energy, APFC & Power Quality
Transformer kVA / Current / Fault Current Calculator
Calculate three-phase transformer currents, loading and a transformer-only terminal fault-current screen.
This tool provides a preliminary engineering calculation for reference. Final equipment selection, design and commissioning decisions must consider manufacturer data, applicable standards, operating conditions and project-specific engineering requirements. It is not certified design output.
Preliminary result
Calculated outputs
Enter values and select Calculate. Results are estimates and do not replace nameplate data, applicable standards, or an engineering review.
Use this calculation
Only calculator parameters and results are transferred. Personal details are collected separately in the destination form.
Formula
I = S(kVA) × 1000 / (√3 × V)
Isc ≈ IFL / (Z% / 100)
Worked example
1000 kVA, 415 V secondary, 6% impedance.
Expected check: Secondary full-load current = 1391; Preliminary terminal fault current = 23.2.
Assumptions
- • Three-phase transformer
- • Infinite upstream bus for the fault-current screen
Limitations
- • Does not represent complete network fault level
- • Excludes motor contribution, generator contribution, cable impedance and upstream source impedance
- • Not a protection-coordination or arc-flash study
Frequently asked questions
Can this result be used for final equipment selection?
No. Use it for a preliminary check, then verify manufacturer data, site conditions, applicable standards and the complete system design.
What does formula version 1.0.0 mean?
It identifies the exact calculation logic used so a saved result can be traced when the formula register changes.
Can Elexorn review my calculation?
Yes. Transfer the result to Request a Quote or Talk to an Elexorn Engineer and add the relevant project or equipment details.