DAMPERS

With the use of overhead power transmission lines, the effects of wind and ice forming on the conductor have begun to be seen. Wind-induced vibrations affecting power transmission lines were examined by taking data directly from the field in the first and second quarters of the 19th century. Depending on the developments in the field of engineering, wind tunnels and various experimental setups have been designed to examine these vibrations. In parallel with the research on wind-induced vibrations, studies have been carried out on the development of dampers that reduce the effects of these vibrations and solutions have been put forward.

KORUCU® vibration dampers effectively dissipate wind energy from the conductor, mitigating vibration stresses to guarantee the longevity of overhead transmission lines

An ominous occurrence within overhead transmission lines is the emergence of high-frequency, short-wave vibrations in conductors, shield wires, and aerial telecommunication cables, triggered by the natural flow of wind. This phenomenon arises from the periodic shedding of vortices on the downstream side of the conductors, known as the Kármán vortex street, instigating vibrations transverse to the wind’s direction. These vibrations manifest within frequencies ranging from 5 to 120 Hz, reaching amplitudes of up to one times the diameter of the conductor.

KORUCU® spacer dampers with 60 years of operational expertise, has attained a prominent position in this sector. We’ve leveraged this experience to enhance our next-generation products, evident in their patented, simplified assembly, innovative damping elements, and semi-automated manufacturing process. Furthermore, our products meet the latest IEC 61854 standards, ensuring optimal functionality.

Bundled conductors are utilized in high-voltage and extra-high-voltage lines primarily for electrical purposes. However, a concerning issue arises with the occurrence of high-frequency, short-wave mechanical vibrations in the sub conductors when wind speeds range between 1 and 7 m/s. These vibrations stem from the alternate shedding of vortices on the top and bottom sides of the sub conductors, inducing cyclic vertical oscillations transverse to the wind flow direction. Frequencies typically range from 5 to 60 Hz with amplitudes reaching up to one conductor diameter. These vibrations impose alternating bending stresses on the conductors, which overlay the static tensile and bending strains. Consequently, this can lead to conductor damage at various clamping points such as suspension and tension clamps, spacers, ranging from fatigue failure of single wires to complete conductor failure.

KORUCU® pendulum dampers demonstrated cost effective control of galloping. No moving parts therefore reliable, consistent maintenance free service, Reduced power outages, allows upgrade of lines within the existing structure due to reduced need for clearances, new lines can be more economically designed using smaller tower structures.

Galloping refers to the dramatic vertical movement that can occur during winter when wind interacts with conductors covered in ice or wet snow. This phenomenon can impact various types of conductors and overhead ground wires utilized in both distribution and transmission lines. It affects both individual and grouped conductors.

Galloping happens when a conductor (or cable) presents an uneven profile to moderate to high wind speeds, typically exceeding 15 mph. When crosswinds encounter an overhead power line coated with ice or wet snow, the conductors can experience significant vertical movements known as galloping. Severe galloping may result in contacts between phases or between phases and overhead ground wires, leading to flashovers and disruptions in power transmission.

Furthermore, the substantial vertical movements associated with galloping can generate dynamic loads capable of loosening bolts, damaging or dislodging insulators and vibration dampers, and causing damage to tower bracings or even structural failures of tower legs. The resulting damage to conductors necessitates repairs, and the loss of power transmission capacity due to failed conductors or hardware can incur significant costs for power utilities.

KORUCU® interphase spacers provide the ideal solution for addressing long-wave vibration.

Overhead transmission lines constitute a significant portion of energy suppliers’ investments. Therefore, their primary concern lies in ensuring the long-term protection of these investments. Air flows can induce vibrations in conductors, which, in the worst-case scenario, lead to conductors striking each other and causing a short circuit, resulting in damage to the overhead lines.

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