kVA ToolsBETA — Short-Circuit
Lab
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Input — System & Utility
| System | Nominal Voltage, L–L (kV) | |
| Voltage Factor cmax | ||
| Frequency (Hz) | ||
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Utility Supply |
Utility Fault Level Method | |
| Utility Fault Level (MVA) | ||
| Utility X/R Ratio |
Input — Transformer Specs
| Rating | Include Transformer | |
| Rated Power SrT (kVA) | ||
| HV Voltage (kV) | ||
| LV Voltage (kV) | ||
| Impedance | Short-Circuit Voltage uk (%) | |
| Load Loss PkT |
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| Apply KT Correction (IEC 60909 §3.3.3) |
Input — Cable / Busbar
| Cable | Include Cable | |
| Conductor Material | ||
| Cross-Section (mm²) | ||
| Length |
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| Number of Parallel Runs | ||
| Temp | Operating Temperature |
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Input — Fault & Withstand
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Fault Type |
Fault Type | |
| Earth Fault Factor (for 1-ph) | ||
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Withstand Check |
Protection Clearing Time tk |
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| Conductor CSA (mm²) | ||
| Conductor Material |
Output — Impedance Breakdown
| At Fault Point (referred to LV, mΩ) | |
| RQ – Utility Resistance | — |
| XQ – Utility Reactance | — |
| RT – Transformer Resistance | — |
| XT – Transformer Reactance | — |
| RL – Cable Resistance | — |
| XL – Cable Reactance | — |
| Total Loop | |
| Rtotal | — |
| Xtotal | — |
| Ztotal | — |
| X/R Ratio (at fault point) | — |
Output — Short-Circuit Currents
| Initial Symmetrical Fault Current | |
| I"k – Initial Symmetrical (kA rms) | — |
| I"k at Transformer LV Terminals (kA) | — |
| Peak & Sustained Currents | |
| κ – Peak Factor (IEC 60909 Eq. 13) | — |
| ip – Peak Fault Current (kA) | — |
| Ib – Breaking Current (kA rms) | — |
| Thermal Equivalent | |
| Ith – Thermal Equivalent (kA rms) | — |
| m + n Factor (IEC 60909 Annex A) | — |
Output — Conductor Thermal Withstand
| Adiabatic Check (IEC 60949 / IEC 60364-5-54) | |
| Withstand Conductor CSA | — |
| k Factor | — |
| Minimum CSA Required (mm²) | — |
| Withstand Result | — |
| Breaker Specification Guidance | |
| Minimum Rated Breaking Capacity | — |
| Minimum Rated Making Capacity | — |
| Minimum Rated Short-Time Current Icw | — |
Output — Parameter Status
| Check | Status |
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| Voltage Factor c | — |
| KT Correction Applied | — |
| Conductor Thermal Withstand | — |
| Fault Level > Tx LV Terminals | — |
| X/R > 10 (DC offset significant) | — |
Output — Network Impedance Build-Up
| Element | R | X | Z | X/R | Σ Z |
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| Enter inputs above to calculate. | |||||
All values in mΩ