NEW EXCITATION SYSTEM FOR INDOOR TESTING OF OVERHEAD CONDUCTORS

In the study of wind-induced motion of conductors of overhead power tr ansmission lines, an indoor test span measuring 30 m or more is normal ly used. The span is generally excited into motion by an electrodynami c-type exciter connected at a span end. This connection increases the stiffness of the span at the point of connection, which will affect th e dynamic characteristics of the test span. A more exact simulation of the indoor test-conductor motion is essential. Simulation of test con ductor motion using the principle of electrodynamic forces between par allel, long conductors is proposed. Indoor test-span motion by this me thod is equivalent to steady crosswinds excitation in the field as dis tinguished from galloping conductors resulting from a combination of w ind direction, velocity, moisture, and temperature. Consequently, the results of vibration experiments also will be more exact. The principl e employed in the new excitation system, the methods of excitation in indoor spans using the principle, and the advantages of the new excita tion system as compared to the presently employed system are discussed in this paper.