IEEE 563-1978 (R2002) pdf free.IEEE Guide on Conductor Self-Damping Measurements.
With the increasing interest and concern regarding the vibration of overhead conductors, and the emphasison the improvement of existing methods and the development of new techniques for controlling the problem,there is a growing requirement for reliable information on the self-damping characteristics of conductors.This parameter is a principal factor in determining the response of conductors to alternating forces,such asarise from wind flow over conductors. This guideline has been prepared for the purpose of encouraginginvestigators contemplating making measurements of the inherent damping characteristics of conductors, toadopt the methods outlined herein. It is anticipated that the resulting information, being in a compatible andconsistent form,will provide a reliable basis for studying the vibration and damping of conductors in thefuture and for the comparison of data of various investigators. The methods and procedures recommendedare not intended for quality control test purposes. SI units are used throughout this document with the commonly employed English units shown in parentheses.
There are several methods available for measuring the energy dissipated by a cable vibrating in a principalmode. These can be divided into two main groups which are usually referred to as the “free vibration”and“forced vibration”methods. The vibration of a cable in a principal mode can be observed only in the absenceof any exciting force, that is, after the force has been disconnected and the other modes have decayed toinsignificant values. The energy dissipated can then be derived from the rate of decay of the vibration.Thismethod can be greatly affected by the method used to disconnect the driving force as the slightest additionaldisturbance of the conductor causes other vibration modes to be generated and this must be avoided.
With the relatively low rates of decay which are usually associated with stranded conductors, the”forcedvibration”method is satisfactory as the contribution of the modes, other than the one which is being excited,is not significant if the frequency of the exciting forces corresponds closely to the resonant frequency of themode under test and if the exciting force is substantially sinusoidal and of sufficiently low magnitude.Twoforced vibration methods are therefore suggested:The”power method”[1] in which the conductor is forced into resonant vibration by an electrodynamicshaker and the power input into the system is determined directly from the product of the excitation forceand the resulting velocity at the point of application of the load.This represents the power dissipated by theconductor provided the two quantities are sinusoidal and are in phase with each other. It assumes also thatthe losses of the terminations are small compared with the dissipation within the conductor. The “powermethod”also permits the mechanical resistance per unit length of the conductor to be determined directlyfrom the ratio of the force to the velocity.IEEE 563 pdf download.