Unless steps are taken to reduce this vibration, failure of the conductor by fatigue wear at the clamp may occur after a few years service. The impedance and the efficiency of the vibration damper have been measured in relationship to frequency and used as input data for the energy balance. Most overhead lines damped with stockbridge dampers have satisfactory performance. Sep 22, 2016 while aeoline vibration is itself not harmful but it may give rise to troubles at points where free vibration is restricted. A damper is basically a device which is so designed to absorbed vibration energy and prevent vibration in transmission line. Review and latest trends in mobile robots used on power.
Windinduced vibration affects the performance and structural integrity of high voltage transmission lines. How does a small size damper reduce vibration in the. In addition, dampers, conditions for damping, free and forced vibrations of the overhead conductor. Then, the main studies carried out on these robots are presented and finally the future of mobile robots used on power transmission lines is discussed. As the need for transmission of communication signals increase, many optical ground wiresopwg are replacing traditional ground wires.
Sep, 2005 a stockbridge vibration damper is a seismic device used for damping overhead power transmission lines. The vortx damper with large and small weights can achieve greater power dissipation and frequency response performance than symmetrical weight stockbridge damper designs. Havard, cea workshop on transmission line asset maintenance, session on. Windinduced vibration or aeolian vibration of transmission line conductors is a common phenomenon. Devices used on transmission lines transmission lines are exposed to a variety of factors, such as corrosion and wind induced vibrations, which cause. Stock bridge damper consists of two hollow weights of special shape fixed at either end of length of line and fastened to the line by aluminum clamp. With this information, vibrec determines how many afl stockbridge vibration dampers or speedgrip spacers will be required for each span and suggests the best location for these accessories. Mar 20, 2011 vibration damper in transmission line.
The dampers have been applied to 750kv transmission lines, and they offer easy installation, slip. Vortx dampers respond to wind induced line vibration that is characterized by high frequency, low amplitude motion a. Journal of sotmd and vibration 1978 60 2, 217237 transmission line vibrations m. Experiments are performed to determine the equivalent viscous damping of the damper. Windinduced vibration of overhead conductors is common worldwide and can cause conductor fatigue near a hardware attachment. For high voltage transmission lines, conductor bundles are used. Pdf aeolian vibration of overhead groundwires is intense in transmission lines located in flat and windy. Aeolian vibration is a low amplitude conductor diameter high frequency 5 to 150 hz phenomenon. Vibration damper for overhead power lines free patents online. Aeolian vibration known as windinduced vibration, has a high frequency and smallamplitude motion, which arises. Study of breeze vibration of overhead transmission lines with.
Jun, 2014 dampers used in electrical transmission lines slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Normally, two dampers are recommended at conductor dead ends with insulator strings, as it is impossible to accurately predict the location of vibration node points. Wo2002007278a1 vibration damper for overhead power lines. 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. 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. The detection and damping of overheadline conductor vibration. Windinduced vibration of overhead conductors is common worldwide and can cause conductor fatigue near a hardware attachment as the need for transmission of communication signals increase, many optical ground wiresopwg are replacing traditional ground wires. Pdf the problem of vibration control of overhead line conductors subjected to. Contribution to the cea workshop on transmission line asset maintenance. The invention provides a stockbridge vibration damper 1 comprising a pair of damping weights 2, 3 joined by a stranded steel cable 4, a clamp 5 attached to the cable at a location intermediate the weights for attachment to an overhead power transmission line. Ozgen september 2012, 92 pages this thesis aims to examine the performance of stockbridge dampers used to suppress aeolian vibrations on overhead transmission lines arising from the wind. Weights made up of cast iron, clamp made up of aluminum alloy, nuts and bolts made up of galvanized or stainless steel and messenger cable made up of galvanized steel. 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. Aeolian vibration of transmission lines has been a.
Stock bridge damper is most popular damper used for prevention of vibration in transmission line. This invention relates to the design and manufacture of stockbridge type vibration dampers for overhead power transmission lines. This paper is a resume of available data concerning the causes of and remedies for wire failure in overhead line conductors subject to the eddy vibration due to steady winds ranging from 5 to 25 m. On the vibration analysis of power lines with moving dampers ma. Modern spacer dampers are characterized by an accurate coordination between the inertial and elastic damping properties. The velocity of the damper clamp shall be remain under the limit of 10 cms. The damper performance tests for the aeolian vibration of. Tangent spans phase conductor and overhead ground wire ohgw level one damping means one damper placement per conductor at one end of the span only. Request pdf vibration damper in transmission line vibration damper in transmission line windinduced vibration of overhead conductors is common worldwide and can cause conductor fatigue. The purpose of the guideline is to guarantee satisfactory performance of the vibration dampers during the lifetime of the overhead transmission line and shall be used for the purchase of vibra tion dampers. In the last twenty years all aluminum alloy conductors aaac have been a popular choice.
Index termstransmission lines, aeolian vibration, stockbridge dampers, laboratory test. The free vibration of a transmission line conductor equipped with a number of stockbridge dampers is modelled by a differential equation of motion of a tensioned beam acted on by concentrated frequency dependent forces, and an exact solution is obtained using integral transformation. First, the fem model was used to develop the equation of motion of the power line conductor. And iee standard is a good way to verity the damper performance. Results of the fem emulation show the calculation accuracy of natural frequency of dampers, and prove that it can effectively restrain breeze vibration of transmission lines by installing dampers.
Simplified vibration model and analysis of a single. The conductor groove of the clamp shall fit the conductor diameter and be free from. Spiral vibration dampers are also effective on certain size overhead. Aeolian vibration, strouhal frequency, messenger, stockbridge damper. The degree of protection needed on a specific line depends upon a number of factors such as line design, temperature, tension, exposure to wind flow, and vibration history on similar construction in the same area. Stored energy from the vibration wave is dissipated to the damper in the form of heat. Pdf download for on the vibration analysis of power lines with. To guarantee the suitability of the dampers a series of three tests has been compiled. They observed that asymmetric stockbridge dampers were. Index termstransmission lines, aeolian vibration, stockbridge. The damper or absorber consists of massspringdampermass system.
The intention of the specification is to guarantee satisfactory performance of the vibra tion dampers during the lifetime of the overhead line. Vibration dampers are used to absorb aolian vibrations of conductor of transmission lines, as well as ground wire, opgw, and adss. Electric power transmission system engineering 2nd edition free ebook pdf download links the book covers all aspects of distribution engineering from basic system planning and concepts through distribution system protection and reliability. Vibration damper, transmission line hardwares kolkata. Us6943290b2 vibration damper for overhead power lines. Simplified vibration model and analysis of a singleconductor transmission line with dampers o barry1, r long1 and dcd oguamanam2 abstract a novel model is developed for a vibrating singleconductor transmission line carrying stockbridge dampers. The method lays foundation for further research on protecting breeze vibration of transmission lines. The vibration dampers function is to minimise the effect of windinduced vibrations. The dampers are so designed that they attenuate the line vibrations by reaching the same frequency as the cable that has wind.
Vibrations dampers are usually employed to handle aeolian, gallop and wakeinduced vibrations in the transmission lines. Pdf control of vibration of transmission lines researchgate. The cause of vibration is that the vortexes shed alternatively from the top. The theory of eddy vibration is first outlined and tests are detailed dealing with the effect on wire failure of such factors as tension and the design of clamp and conductor. Vibration dampers 1700,1700aa series vibration protection recommendations spacing notes notes. The effects of turbulence will be discussed later in this report. For high voltage transmission lines, conductor bundles.
The self damping characteristics of a conductor or ohsw are basically related to. Stockbridge damper vortx vibration damper preformed line. Most of transmission lines utility organizations used stockbridge dampers to control. Ribe vibration dampers effective protection against conductor vibrations karman vortex street. Ribe vibration dampers remove the wind energy from the conductor and reduce vibration stresses sufficiently to ensure a long life for the overhead transmission lines. Vibration in transmission line is solved by using specially designed dampers. Vibration damper in transmission line vibration damper in. Apr 19, 2019 how vibration damper works in transmission line. Numerical examples of the free vibration analysis show a significant. Overhead transmission line conductors are peculiarly prone to aeolian vibration generated by eddy vortices formed as the wind passes across the conductor. Table of contents afl fiber optic cable, transmission and. Pdf study of new dampers for application to overhead.
Keywords aeolian vibration, transmission line vibration, overhead conductors, vibration dampers 3. Vibration control of overhead transmission lines kasap, huseyin m. Simplified vibration model and analysis of a singleconductor. The vibration dampers are tested at this vibrating velocity in an endurance test. Stockbridge vibration dampers comprise of a pair of weights joined by a stranded steel cable commonly known as a messenger cable and a clamp attached to the cable at a location intermediate the weights for attachment to an overhead. Lines damaged by vibration may have to be derated or even taken out of service until repairs can be made. Feb 22, 1972 a vibration damper for an overhead cable having a cshaped cushioned elastomer lined suspender engaging the cable and a vibration damper suspended below it.
Electric power transmission system engineering 2nd edition. System feeders distributors service lines or service mains. Vibration and vibration dampers in transmission line. The analytical expression of the kinetic energy of the cable is compared with the amount of dissipated. Havard, cea workshop on transmission line asset maintenance. Vibration modeling and analysis of a single conductor. Vibration damper in transmission line electrical notes. Transmission conductor vibration dampers stockbridge type1700 series damper to dissipate vibration, or wake up, at lower energy inputs. Aeolian vibration, transmission line vibration, overhead conductors, vibration dampers. Aeolian vibration is a low amplitude conductor diameter high frequency 5 to 150. Technical guideline for vibration dampers with preformed helical rods for.
Vibration dampers are used to absorb aolian vibrations of conductor of transmission. This provides maximum effectiveness in controlling the levels of subconductor motions. Ohsw on transmission and distribution lines can produce damage that will negatively impact the reliability or serviceability of these lines. These two modes combined with the 19 strand messenger wire give afls stockbridge damper the widest range of vibration coverage in the industry. About 78% of these are power accessories, 5% are power distribution equipment. A wide variety of transmission line fitting vibration dampers options are available to you, such as material.
Rao department of applied liechanics, indian institute of technology, madras 600036, lndia received 31 august 1977, and hi revised form 23 march 1978 various forms of dampers are used to suppress vibrations in transmission lines. The authors emphasize the importance of choosing appropriate design tension, type, quantity and placement of vibration dampers to avoid failure of lines. Maintenancefree for the whole lifetime of the line. Overhead transmission lines vibrationdampers svenska kraftnat. Dampers are also used as supplemental protection at deadends. The invention provides a stockbridge vibration damper comprising a pair of damping weights joined by a stranded steel cable, a clamp attached to the cable at a location intermediate the weights for attachment to an overhead power transmission line.