Torsional stability of bundle conductors

An extensive program of tests to determine the torsional behavior of two- and four-conductor bundles with various subspan arrangements is described. The tests provide data on torsional stability and on torsional stiffness, necessary for development of galloping control. An idealized model of a multiconductor bundle has been analyzed and a theory for the torsional behaviour has been obtained. Based on the experimental and theoretical data, torsional stability can be ensured under the worst conceivable unbalanced loadings with only two or three spacers per span, provided there is no conductor slippage in the spacer clamps.