Old video i found on aeolian vibration fundamentals by preform products. The aeolian vibration frequencies are range wind speed 0. The study results provided guidance to the design of aeolian antivibration method. They are characterised by small amplitudes of vibration one conductor diameter with frequency between 5 and 100 hz, depending on the conductor size and tensile load. Beginning vibration analysis with basic fundamentals. The aeolian vibration is a wellknown phenomenon affecting both single and bundle tl.
Vibration can be defined as simply the cyclic or oscillating motion of a machine or machine component from its position of rest. Aeolian vibration is a type of motion caused by wind on conductors and overhead shield wires of transmission and distribution lines. As this steady stream of air passes across the pole, vortices are formed on the backside of the structure. Combined with the theory of forced vibration analysis, lu 6 used impedance matrix transformation method to analyze the vibration response of conductor damper. If the amplitude of such vibration is sufficient, it can result in strand fatigue andor fatigue of conductor accessories. Showcases secondstage, or aeolian, vibration in a steel or aluminum light pole.
Im an electrical engineer, and understand how a twisted pair of wires can be used to reduce noise in the presence of magnetic fields. The phenomenon know as aeolian or second mode vibration is caused by lowvelocity, steady winds, normally ranging from 535mph and giving rise to frequencies of 220hz. Increased tension on bundled conductors appears to decrease their tendency to create induced oscillation and galloping. Vecchiarelli 5 used the finite difference method to study response of aeolian vibration of the. In engineering practice, we are almost invariably interested in predicting the response of a structure or mechanical system to external forcing. Besides, the frequencies of lines are in accordance with frequencies in theory and. The damper performance tests for the aeolian vibration of. This piece disturbs the harmonic cycling of the shaft aeolian vibrations by touching the inside surface of the pole in a random and spiral manner. This vibration is believed to be predominantly caused by air vortexing around the structure. Windinduced vibration and the effects on steel and aluminum. From basic mechanics it is known that the bending strain in a beam. Aeolian vibration free download as powerpoint presentation. The spiral vibration damper figure 10 has been used successfully for over 35 years to control aeolian vibration on these smaller sizes of conductors and wires. Aeolian vibration is one of the most important problems in transmission lines because it represents the major cause of fatigue failure of conductor strands or of items associated with the support, use, and protection of the conductor.
Install a vibration dampener if aeolian vibration is suspected, it is recommended to take next steps to remedy the situation as quickly as possible. The solutions listed in the preceding sections give us general guidelines for engineering a system to avoid or create. It is common to refer to the transmission and distribution elements as networks or again, as systems. Aeic encourages research and enables the exchange of technical information and best practices through a. Fluidstructure interaction fsi analysis was taken based on the coupling models, from which the property result of aeolian vibration numerical simulation was. Principal modes 44 generalized and coupling 45 principal coordinates 158 46 modal analysis.
May 10, 2017 formation of the solar system documentary the inner secrets of planets and stars touch your heart 479 watching live now. Research on aeolian vibration of a conductor based on. Peters beginning vibration 2 introduction understanding the basics and fundamentals of vibration analysis are very important in forming a solid background to analyze problems on rotating machinery. Aeolian vibration is a low amplitude conductor diameter high frequency 5 to 150 hz phenomenon. Research on aeolian vibration of a conductor based on finite particle method. In order to research the problem of aeolian vibration occurred on single conductor in this paper, adina program was applied to set up the model of fluid domain and structure domain. A stockbridge damper is a tuned mass damper used to suppress windinduced vibrations on slender structures such as overhead power lines and long cantilevered signs. A substation is an installation that interconnects elements of an electric utilitys system. Relation of natural frequency to weight of supported body and stiffness of spring eq. Aeic was founded by thomas edison and his associates in 1885 and is one of the most experienced associations in the electric energy industry. This sustained vibration activity takes the form of discrete standing waves with forced nodes at the support structures and.
A potential solution for longdistance power transmission leakage stray voltage from overhead lines causing a fluorescent lamp to glow electricity a complete beginners guide covering watts, amps, volts, ohms and kwh. Online monitoring analysis of aeolian vibration of jiangmentongtangjia 220kv transmission line. Aeolian vibration is characterised by low amplitude conductor diameter high frequency 5 to 150 hz. Beginning vibration analysis connection technology center, inc. The spiral vibration damper is an impact type damper made of a rugged nonmetallic material that has a tight helix on one end that grips the.
Research advances of aeolian vibration of damperline system. Though the extent of corona and radio noise is impacted by elevation air density, and other factors such as conductor surface condition and moisture, the bundle dimensions are the primary factor in mitigating the onset of the corona while increased aluminum content serves to reduce line losses and increase power flow, increased diameter also increases the conductors. Early detection of this problem provides a greater solution base. The association of edison illuminating companies aeic. These elements can include generators, transmission lines, distribution lines, and even neighboring utility systems. Con tents preface xi chapter1 introduction 11 primary objective 1 12 elements of a vibratory system 2 examples of vibratory motions 5 14 simple harmonic motion 15 vectorial representation of harmonic motions 11 16 units 16 17 summary 19 problems 20 chapter 2 systems with one degree of freedomtheory 21 introduction 23 22 degrees of freedom 25 23 equation of motion. Index termstransmission lines, aeolian vibration, stockbridge dampers, laboratory test.
A potential solution for longdistance power transmission leakage stray voltage from overhead lines causing a fluorescent lamp to glow electricity a complete. However, i recently noticed the power company replacing the c. Online monitoring analysis of aeolian vibration of. The body is in equilibrium under the action of the two forces. Fluidstructure interaction fsi analysis was taken based on the coupling models, from which the property result of aeolian vibration numerical simulation was acquired. Pdf aeolian vibrations on powerline conductors, evaluation. The amplitude of aeolian vibration less than diameter of the conductor. Aeroelasticity problems can be prevented by adjusting the mass, stiffness or aerodynamics of structures which can be determined and verified through the use of calculations, ground vibration tests and flight flutter trials.
Why are twisted pair cables used in electric power. In contrast to galloping and subconductor oscillations, aeolian vibration is characterized as high frequency, low amplitude motion. Ohsw on transmission and distribution lines can produce damage that will. Formation of the solar system documentary the inner secrets of planets and stars touch your heart 479 watching live now. In a gentle wind, a power line will sing, just as a catgut or nylon string will sing in an aeolian harp. Pdf ultrahighvoltage transmission line is prone to severely aeolian vibration.
Aeroelasticity is the branch of physics and engineering that studies the interactions between the inertial, elastic, and aerodynamic forces that occur when an elastic body is exposed to a fluid flow. Aeolian vibration can be altered by as little as the shape of the structure, changing the fixture style or location, or having an object such as a tree or building alter the wind pattern. Electric substations with equipment used to convert highvoltage, extrahighvoltage ehv, or ultrahighvoltage uhv transmission lines to the intermediate voltage subtransmission lines or to switch subtransmission circuits operating at voltages in the range of 34. Pdf aeolian vibrations on powerline conductors, evaluation of. Study on aeolian antivibration of bundled conductor of. Harmonics stings on a stringed instrument such as a guitar or an aeolian harp can vibrate in a number of different ways. To be valued as the premier operationsfocused trade association in the electric energy industry. Unit 7 vibration of mechanical vibration of mechanical. Although any system can oscillate when it is forced to do so externally, the term vibration in mechanical engineering is often.
Aeolian vibration dampers on power lines with images. Vibration control is aimed at reducing or modifying the vibration level of a mechanical structure. The aeolian vibration control of the conductor is based on the energybalance principle that takes accounts for the windenergy input, the energy dissipated by the conductor due to hysteretic selfdamping properties or equivalent viscous damping and, eventually, the energy dissipated by the stockbridge dampers. Figure 2 vibration recorded on 38 ohsw 41 hertz sustained aeolian vibration activity occurs when the vortex frequency closely corresponds to one of the natural vibration frequencies of the span of conductor or ohsw. The frequency of aeolian vibration ranges from 3 to 50 hz and the wind speed ranges from 1 to 7 ms. Sinusoidal vibration top and random vibration bottom 1. Aeolian vibration, which is the subject of this paper, is associated with smooth nonturbulent winds in the range of 2 mph to 15 mph, and can occur on a daily basis. Study on aeolian antivibration of bundled conductor of large. My task was to study aeolian vibration as it occurred, not in a harp, but in their power lines. Aeolian vibration causes damaging stress fatigue to the cable and represents the principal cause of failure of conductor strands. Pdf study on aeolian vibration suppression schemes for large.
The frequency of aeolian vibration ranges from 3 to 50 hz and. The effect becomes more pronounced with increased cable tension, as its natural selfdamping is reduced. Wind induced aeolian vibrations of conductors and overhead shield wires. Power balance approach, applicable to multimodal analysis.
Contrary to passive methods dampers, shock mounts for machines, acoustic packing, various foams, etc. Mechanism caused by smooth winds with velocity pdf when a smooth stream of air passes across a cylindrical shape, such as a conductor or ohsw, vortices eddies are formed on the leeward side back side. Without dampers, the amplitude of vi bration very much depends on conductor self damping, which may be very low. Finally, we solve the most important vibration problems of all. Aeolian vibration often occurs in the highvoltage transmission overhead lines, and the amplitude of conductors has close relationship with conductors fretting wear. Wenping xie 1, tian peng2, kai xiao, and jian zhang2. It shows that performances of dampers on the lines meet the standard of. Cfd numerical simulation of aeolian vibration of single. Research on aeolian vibration of a conductor based on finite. Switching between time and frequency is a common tool used for. The simplest vibration is when the whole string vibrates up and down top but it is also possible to fit. Simulation study on amplitude of the overhead line based. Aeolian vibration is generally less pronounced on bundled conductors due to the effect of spacers andor spacer dampers installed at relatively close intervals along the line.
That vibration can, eventually, cause the wire to fatigue and break. At present, there is a lot of literature researching on aeolian vibration of a conductor at home and abroad. Me 563 mechanical vibrations fall 2010 12 1 introduction to mechanical vibrations 1. Scribd is the worlds largest social reading and publishing site. Aeolian vibrations occur almost on any transmission line, for low to moderate steady winds. Suppose that we need to stop a structure or component from vibrating e. The damper is designed to dissipate the energy of oscillations in the main. Here is the extension of the spring after suspension of the mass on the spring.
Beginning vibration analysis with basic fundamentals by. Windinduced vibration and the effects on steel and. The dumbbellshaped device consists of two masses at the ends of a short length of cable or flexible rod, which is clamped at its middle to the main cable. The ends of a power line span, where it is clamped to the transmission towers, are at most risk. Aeolian vibration test for composite technologies corporation ref. The study of aeroelasticity may be broadly classified into two fields. The control of the aeolian vibration is deputed to the use of a suitable damping system. The theory of the aeolian tone the theory of aerodynamic sound is based upon the wave equation for the fluid density p v2 i 02 p 4ax, 1 a2 tu oxj where tu p. It it designed to be used on opgw and conductors with an outside diameter less than 0. This numerical scheme is based on empirical models developed to represent the vortexinduced lift force from the wind as well as the forces of dissipation. Plps spiral vibration damper reduces aeolian vibration the high frequency, low amplitude vibration caused by horizontal wind passing across the line. International journal of engineering and technology, vol.
It is very difficult to measure actual amplitude of working conductor, so obtaining the amplitude of the conductor by the means of simulation is of practical significant to research quantitatively the relationship of the amplitude. The vibration dampening system consists of a length of chain encased in a plastic tube that runs approximately twothirds the length of the pole. In the forcedconvection cooling mode, incoming wind can also induce the vibration of a transmission line 8, where aeolian vibration 9 10 11 is the most likely to occur and has the longest. An iterative finitedifference scheme is derived to predict the vertical, steadystate, monofrequent, aeolian vibration of a single conductor span with a stockbridgetype damper attached. About us united lighting standards has been committed to designing, fabricating, finishing, and packaging highquality steel and aluminum poles since 1971. Overhead line aeolian vibration fibreoptic sensor bragg grating measurements. Aeolian vibration known as windinduced vibration, has a high frequency and smallamplitude motion, which arises.
Wenping xie1, zuyan zhang 2, ningbo xu, li li 2, zheng wang, and xiaoyu luo1. The study results provided guidance to the design of aeolian anti vibration method. Third, two aeolian vibration schemes, the first one with vibration dampers only and the second one. Transmission, sub transmission and distribution substation 4. Mar 09, 2016 showcases secondstage, or aeolian, vibration in a steel or aluminum light pole. Aeolian vibration fundamentals by preform products youtube.
1492 1586 1177 1453 1287 794 1605 47 463 374 581 1657 894 402 333 1033 347 777 487 777 161 1094 1568 63 479 1275 1127 557 754 772 135 1228 281 469 823 335 483 1121 537 308 1078 164