Educational simulator only. This tool illustrates simplified symmetrical-component concepts. It does not perform NEC, NFPA 70E, IEEE 1584, IEEE C37, IEC 60909, IEC 62271, UL SCCR, or equipment-rating compliance analysis. Do not use it for design, labeling, protection settings, or equipment rating decisions. Assumptions: prefault V = Source Voltage / Transformer Primary kV, Z2 = Z1 for all elements, transformer X/R fixed at 8, faults on the transformer secondary, no motor/generator/inverter contribution, no prefault load. Primary-side currents for unbalanced faults are approximate (vector-group ±30° phase shift not modeled). See the Analysis tab for what this tool does not check.
⚡ Single-Line Diagram
Radial teaching system: grid source → transformer → cable → load. Scroll horizontally on narrow screens.
📈 Representative Fault Current Waveform
📋 Event Log
Illustrative sequence of events (timestamps are representative, not simulated)
0.000sSystem initialized. Ready for fault simulation.
🔍 Fault Path Visualization
⚡ Bus Phase Voltages During Fault
Each bus shows |Va|, |Vb|, |Vc| (phase-to-ground) in per-unit of the bus nominal voltage (100% = nominal, not prefault), reconstructed from V0, V1, V2 at that bus. The prefault voltage in pu is shown in the Fault Analysis box.
📊 Impedance Breakdown (Positive Sequence, path to fault)
Series impedances in pu on the system MVA base. Transformer and cable are impedances, not fault current sources.
🛡 Protection Assessment (Instantaneous Pickup Check Only)
🌐 Sequence Components at Fault Bus
⚡ Phase Fault Currents
❌ What This Tool Does NOT Check
This is an educational symmetrical-component teaching model. It performs no code, standards, or equipment-rating compliance analysis. In particular it does not evaluate:
- NEC / AHJ available fault-current field marking
- OCPD interrupting rating / AIC
- Equipment SCCR / withstand rating
- Series ratings / current-limiting devices
- IEEE 1584 incident energy / arc-flash boundary
- IEEE C37 / IEC breaker making, latching, interrupting, TRV, close-and-latch duty
- IEC 60909 c-factor, max/min cases, motor/generator/inverter contribution
- Protective-device TCC coordination
- Conductor temperature correction
- Utility min/max source cases
Use manufacturer ratings and the applicable IEEE/IEC/NEC standard, evaluated by a qualified engineer, for any real design, labeling, or protection decision.
Preset Scenarios
Click a scenario to load its parameters and run the fault. Each card lists what the scenario is designed to demonstrate.