Abstract
Transmission lines and towers can be regarded as a coupling system. In order to clarify its fundametal dynamic characteristics, a few idealized models are studied and discussed. The authors adopt the mixed formulation and extend the algorithm so as to solve the coupling system. Conclusions are as follows: (1) In the low frequency range, the transverse wave of transmission lines affects the behavior of towers. If the lines of the adjacent spans are in the transition mode and each of them out-of-phase, then the tower between them is deformed significantly. (2) In the high frequency range, trasmission lines are excited in the longitudinal mode. Each one of natural frequency of the single tower system undergoes division into some ones of the coupling system. The range between the lowest "branching" frequency and the highest one seems to be separated with the increasing cable number (parameter H). These dynamic characteristics may be explained, to a certain extent, by "the coupled pendulum model" analogically.
