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Main >> Applications >> Sample problems >> Line-to-line short circuit

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.

**Problem Type:**

Plane-parallel problem of transient magnetics.

**Geometry:**

Tangent tower design. All dimensions are in meters.

Wire design

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.

**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) *I*_{max} = 7000 A.

Electromagnetic force of interaction between phases *A* and *B* *F*_{A-B} = 1780 N/km.

Illustration of the short-circuit currents: