Line-to-line short circuit
Line-to-line short circuit 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 line-to-line short circuit in QuickField.
Problem Type:
Plane-parallel problem of transient magnetics.
Geometry:
Tangent tower design. All dimensions are in meters.
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Wire design |
Line-to-line short circuit |
Given:
Rated voltage (RMS) Urated = 110 kV;
Rated current (RMS) Irated = 440 A;
Line lengh l = 20 km;
Loading parameters Rload = 100 Ohm;
Lload = 0.23 H.
Problem:
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 resistance which varies in time. This dependence is implemented using the electrical conductivity as a function of the temperature, which is also function of time – as σ(T(t)) function.
Results:
Short-circuit current (amplitude) Imax = 7000 A.
Electromagnetic force of interaction between phases A and B FA-B = 1780 N/km.
Illustration of the short-circuit currents:
 Download simulation files line_to_line_short.zip.
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