Study on Galloping Oscillation of Iced Twin Bundle Conductors considering the Effects of Variation of Aerodynamic and Electromagnetic Forces

Table 3

Global natural modes and frequencies of the lines.

Direction	Mode	Natural frequencies (Hz)
		200 m span line
		Symmetric spacer layout	Unsymmetric spacer layout
In-plane		0.476	0.475
		0.680	0.676
		1.026	1.017
Out-of-plane		0.341	0.340
		0.683	0.678
		1.019	1.011
Torsion		0.567	0.566
		0.847	0.872
		1.307	1.224