Transmission line pole. All dimensions are in meters.

Aluminum Conductor Steel Reinforced (ACSR)

Scheme of transposition. Transmission line length l = 120 km

Given: Line rated voltage U_{line} = 110 kV
R_{load} = 100 Ohm, L_{load} = 0.23 H.

Problem: Define transmission line phase inductance.

Solution: At longer power lines wires are transposed according to the transposing scheme. Each of the three conductors must hang once at each position of the overhead line. On transmission lines of 110-500 kV rate one complete cycle of a transposition should be carried out if the line length exceeds 100 km. The transposition should be carried out so that total lengths of transmission line parts were approximately equal.
The length of our line is 120 km. The distance between transposition points is 40 km.

The simulation model includes field and circuit parts. There are three encapsulated field parts connected one with another by the external circuit. Each conductor consists of aluminum and steel wires:

Full impedance of a line develops of separate parts impedances and can be found as total voltage drop divided by a current:
Z_{line} = (U1 + U2 + U3) / I.

Impedance of a line can be presented as the sum of active resistance (R_{line}) and inductive reactance (X_{line}):
Z_{line} = R_{line} + jX_{line}.

Line inductance can be calculated as:

L = X_{line} / 2 π f,
where X_{line} - line phase inductive reactance;
f - frequency of the alternating current.

Results: Table of the measured currents and voltages for a phase conductors

Part 1

Part 2

Part 3

Total

Voltage U_{A}, V

5676 + j2832

5943 + j2800

6142 + j2366

17761 + j7998

Voltage U_{B}, V

-5078 + j4213

-5292 + j3501

-5438 + j3671

-15808 + j11385

Voltage U_{C}, V

-547 - j6546

-1111 - j6494

-297 - j6331

-1955 + j19371

Current I_{A}, A

263 - j270

263 - j270

Current I_{B}, A

102 + j376

102 + j376

Current I_{C}, A

-363 - j93

-365 - j93

Resistance Z_{A}, Ohm

17.7 + j48.6

Resistance Z_{B}, Ohm

17.7 + j48.6

Resistance Z_{C}, Ohm

17.7 + j48.6

Inductance of a phase : L_{phase} = L_{A} = L_{B} =
L_{C} = 0.155 H (total length 120 km).