短路电流计算器 — 公式
## Transformer Short-Circuit Current
The prospective short-circuit current at the transformer secondary is limited by the transformer impedance.
### Formulas
**I_FL = kVA x 1000 / (sqrt(3) x V)** (full load current)
**I_SC = I_FL / (Z%/100)** (short-circuit current)
where Z% is the transformer impedance expressed as a percentage. This is the maximum fault current available at the transformer terminals, ignoring cable impedance downstream.
The prospective short-circuit current at the transformer secondary is limited by the transformer impedance.
### Formulas
**I_FL = kVA x 1000 / (sqrt(3) x V)** (full load current)
**I_SC = I_FL / (Z%/100)** (short-circuit current)
where Z% is the transformer impedance expressed as a percentage. This is the maximum fault current available at the transformer terminals, ignoring cable impedance downstream.
计算示例
A 500 kVA transformer, 400 V secondary, 5% impedance.
- I_FL = 500,000 / (1.732 x 400) = 721.7 A
- I_SC = 721.7 / 0.05 = 14,434 A = 14.43 kA
- Switchgear must have a breaking capacity above 14.43 kA.