DC ARC FLASH · 3-D MHD SIMULATION MODEL

DC Arc Flash Calculator

An interactive implementation of the arc model derived from 3-D magnetohydrodynamic simulation.

Open the calculator Read the paper →

Rau & Lee · IEEE Transactions on Industry Applications, 2016

3-D MHD simulation of a DC arc — temperature isosurfaces.

Interactive calculator

Fault conditions

Published test cases

Load a case from the paper and reproduce its published result.

System voltage

Bolted fault current

Electrode gap

Arcing duration

Working distance

Equipment

Result · Rau–Lee model

Incident energy at working distance

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Arc-flash boundarydistance to 1.2 cal/cm² — —

Arc energy —

Arc current

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Arc voltage

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Arc power

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Arc resistance

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Validation against legacy DC arc models How the Rau–Lee model compares with three historical models for the same fault.

Model	Arc current	Arc voltage	Arc power

Characteristic curves

Arc voltage vs arc current

Rau–Lee V–I at several gaps; marker = your operating point.

Arc voltage vs gap

How arc voltage grows with electrode gap.

Incident energy vs working distance

Shaded bands = PPE thresholds. Marker = your working distance.

How it works

A nonlinear arc in a DC circuit

The arc behaves as a nonlinear resistance in series with the source.

The Rau–Lee relations

V_arc = (13.11 + 0.287 L^1.238) I_arc^0.154

R_arc = V_arc / I_arc

P_arc = I_arc · V_arc

I_t = 10 + 0.2 L (transition current)

The calculator solves this implicit equation numerically for the arc current.

Valid for arc current above the transition current.

DC equivalent circuit

V_s = I_arc·R_s + V_arc(I_arc, L)

The simulation

3-D magnetohydrodynamic arc

DC arc evolution — temperature isosurfaces.

The model is grounded in a full 3-D MHD simulation coupling Navier–Stokes with Maxwell's equations.

Arc length at 3 inch gap — Arc length, 3-in gap

Arc length at 1 inch gap — Arc length, 1-in gap

The paper

“A new DC arc model based on 3-D DC arc simulation, capable of providing comparable results to available lab testing.”

DC Arc Model Based on 3-D DC Arc Simulation

Shiuan-Hau Rau and Wei-Jen Lee

IEEE Transactions on Industry Applications, vol. 52, no. 6, pp. 5255–5261, 2016.

DOI10.1109/TIA.2016.2587760

View on IEEE Xplore