Phase to phase fault

QuickField simulation example

Phase to phase fault is one of the most widespread damages of the transmission lines in electrical networks (15-20 % from total number of failures). This model shows how to simulate the phase to phase fault in QuickField.

Engineering question
How to find line to line short circuit transient currents and forces?

Engineering answer
Set up a plane-parallel QuickField Transient Magnetics problem for a line-to-line short circuit and evaluate transient currents and forces from computed field results.

Typical applications
overhead transmission lines, power line conductors, faulted transmission circuits

• Download simulation files (files may be viewed using any QuickField Edition).

Problem Type
Plane-parallel problem of transient magnetics.

Geometry

Aluminum Conductor Steel Reinforced (ACSR):

Line-to-line short circuit:

Given
Rated voltage (RMS) U_rated = 110 kV;
Rated current (RMS) I_rated = 440 A;
Line length L = 20 km;
Loading parameters R_load = 100 Ohm; L_load = 0.23 H.

Task
Determine the transient process currents after a short circuit occurred. Find the electromagnetic forces acting on the lines during this process.

Solution
To solve this problem it is necessary to simulate both field part and circuit part. The scheme of connection of power supply phase windings, loading, elements of the circuit and short-circuit bridge is presented in the circuit model, created by the QuickField Circuit Editor.
Short-circuit bridge is a QuickField block with the electrical conductivity which varies in time:
σ(t) = 0.01 + 56e6 * STEP(t - 1).

Results
Electromagnetic force of interaction between phases A and B is f_A-B = 2.6 N/m.

Maximal short-circuit current I_max = 8 kA.

• Video: Phase to phase fault. Watch on YouTube.
  
• View simulation report in PDF