Galloping of bundle conductor

A useful design tool is developed for a bundle conductor of an electrical t ransmission line by using a three-degree-of-freedom hybrid model. The model is adaptable because it incorporates numerical mode shapes determined by n umerically employing the finite element technique to form relevant matrices . On the other hand, it is quite computationally efficient because analytic al expressions are used to investigate the initiation and steady state ampl itudes of galloping. The model accommodates interactions of the vertical, h orizontal and torsional movements, non-linear aerodynamic loads, a non-unif orm ice geometry, distributed and discrete galloping control devices, and a variation of the wind along a span. By neglecting the sub-span motions bet ween the conductors, a bundle is modelled as an equivalent single conductor so that the initiation conditions for galloping, periodic and quasi-period ic states and their stability conditions are considered by taking advantage of previous achievements for a single conductor. Numerical examples are pr esented to assess the accuracy of the results obtained from the model in co mparison with analogous data from a more sophisticated finite element analy sis. Parametric studies are reported for limit cycle amplitudes with variat ions of the critical wind speed, wind speed above the critical wind speed, static tension and span length. (C) 2000 Academic Press.