Distribution Fault Study

11 kV radial feeder protection simulator

Calculated

Study Inputs

Source & Transformer
Feeder
Fault

Single-Line Diagram

Single-line feeder diagram with fault marker Utility Source CB-1 10 MVA CB-2 Fuse-1 Fuse-2 Load Fault 2.60 km

Calculated Results

Elevated
Fault Current 3.39 kA RMS symmetrical
Per-Unit Voltage 0.899 pu At fault point
Fault MVA 64.65 MVA Calculated duty
X/R Ratio 1.26 To fault point
✓
Operate Fuse-1 Primary clearing in 1.36 s
Priority Device Trip Time

Time-Current Coordination

Study Notes

Calculations use a transparent per-unit approximation for study comparison. Real protection settings must be validated against utility standards, manufacturer curves, arc-flash requirements, and field measurements.

Base Current
524.86 A
Total Impedance
0.101 pu
Backup Device
CB-2 Relay