A mobile vibration laboratory for overhead lines

MOUNTING REQUIREMENTS for capital investment and dependability per circuit-mile of transmission construction have given imminent importance to the elimination of incipient fatigue failures of overhead conductors and associated hardware. The increasing attention devoted to these fatigue problems in recent years has been manifested by the expansion of both laboratory and field activity in cable vibration research and in the development of improved test methods and equipment for obtaining pertinent data. However, relatively few field investigations to date have utilized the modern instrumentation techniques common to the laboratory, and those studies have been confined to nonenergized test spans since the transducers employed in modern instrumentation require electric connections to grounded recording equipment. The mechanical instruments used in energized line studies have been entirely inadequate for accurately measuring the many pertinent variables involved. Consequently, there are insufficient field data to establish quantitative relationships or to permit realistic correlation with laboratory results.