Quantification of Induced Effects on T-pylon Transmission Lines

Induced voltages and currents on the non-energized circuit of a transmission line occur due to the electromagnetic field generated by the energized side of a double-circuit transmission line. These induced effects can produce considerably high currents and voltages along the line length, which might affect the safety of workers during maintenance operations. This paper investigates the steady-state currents on the earth wires, phase conductors, and tower base of a double-circuit 400-kV transmission line with a length of 13.2 km using the T-pylon configuration. For this purpose, it is assumed that one circuit is fully energized by a 3-phase sinusoidal voltage source and its rated current, while the other is non-energized, and earthed at both terminal substations. The software ATP-EMTP<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> is adopted for the power system modeling and numerical simulations. Results demonstrated that the induced currents on the earth wires, phase conductors, and tower base vary significantly along the length of the line. Maximum current values (rms) of 137 A and 23 A were computed on the earth wires of the energized and non-energized side, respectively.