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Three-Phase Fault Current Estimate Calculator

An idealized positive-sequence Thevenin estimate using explicit fault-point inputs.

01 / User inputs

Fault-point positive-sequence inputs

|I₁| = |V₁,prefault| ÷ |Z₁,th| · I3φ,RMS = VLL,prefault ÷ (√3 × |Z₁,th|) · Ssc = √3 × VLL × I3φ

Enter the prefault voltage and positive-sequence Thevenin impedance for the identical fault point and consistent system base. Voltage: V RMS; impedance: Ω.

02 / Estimate

Idealized three-phase fault estimate

Enter all parameters

Enter all explicit parameters to calculate.

Method and boundaries

Uses the prefault line-to-line RMS voltage and positive-sequence Thevenin impedance magnitude at the same fault point and on a consistent base. It estimates only a bolted balanced three-phase symmetrical RMS current.

It does not implement IEC 60909 correction factors, asymmetrical or peak currents, other fault types, breaker duty or protection decisions.

FAQ

What does this calculator compute?

It estimates a bolted, balanced three-phase symmetrical RMS current from the prefault line-to-line RMS voltage and the positive-sequence Thevenin impedance magnitude at the same fault point.

What has to be consistent?

Voltage and impedance must refer to the same fault point and the same system base. The tool does not build the network for you.

What does it not calculate?

It does not implement IEC 60909 correction factors, asymmetrical or peak current, other fault types, breaker duty, or protection decisions.

Source records