Fostering galloping solutions grounded in technical research.
Twisting the conductor to control galloping is a complex challenge. Over 80 technical papers, published in professional and industry journals have been written on the subject by A.S. Richardson, PE.
- CIGRE – State of the Art of Galloping
- Designing Quad Bundles against Galloping
- Dynamic Analysis of Lightly Iced Conductor Galloping in Two Degrees of Freedom
- Limiting Dynamic Loads on Tall Towers
- Mechanical and Electrical Properties of Large Bundled Conductors
- Performance Requirements of Vibration Dampers
- Predicting Galloping Amplitudes I
- Predicting Galloping Amplitudes II
- Predicting Galloping Fatigue Cycles in Quad Bundles
- Study of Galloping Conductors on 230 kV Line
- Vibration Damping Required for Overhead Lines
- Vibration of Single and Bundled Conductors
WINDAMPER and AR Twister. Research Consulting Associates was approached by the Public Service Company of Colorado to determine if galloping of a new 230kV bundled line would require anti-galloping devices. The project evaluated three sections of line, all running E-W. Average span length was 800-1000 ft. Studies included plotting galloping ellipses for extreme wind and a long span with 36 ft. sag. Plot graphs revealed double amplitude of gallop a 35 MPH for various span lengths. Clashing was predicted on all span lengths greater than 820 ft.
PS Colorado requested an assessment of the potential to reduce predicted galloping amplitude of the spans by twisting the conductor to reduce aerodynamic lift. It was determined that if the lift can be reduced by 40% or more, clashing will not occur.
A galloping control solution of AR Twisters was provided.
AR Dual Damper / AR Twister Slider. Research Consulting Associates was approached by Key West City Electric Company to study the likely causes of damage resulting from hurricane force winds on a 138kV line. When 30 MPH winds caused violent galloping and outages of the 30 mile line in the Florida Keys. Research Consulting Associates completed the analysis and recommended a pilot project on two selected spans. Six units of AR Twister|Sliders (formerly Dual Damper) were installed. When the 30 MPH wind conditions returned, it was observed that the lines treated were totally quiet while untreated lines continued to gallop violently. At the conclusion of the pilot project, AR Products was hired to provide several hundred Twister units for the remaining spans. This model is effective for very light weight conductors.
AR Lightweight Spacer / AR Spacer Twister. AR Products was approached by Cedar Point Wind Farm, Limon Colorado to recommend a solution to galloping along the 200 miles of 230kV bundled transmission line. Developed by RES Americas, the line is located approximately 80 miles east of Denver. Construction of the wind farm was completed in 2011. The wind farm will deliver electricity to The Public Service Company of Colorado, and Xcel Energy Co.
The project is comprised of 139-1.8 MW turbines. High winds, ice and rugged terrain contributed to high amplitude galloping by the vertical bundled conductors. A span-by-span analysis was completed and a recommendation was made to deploy the AR Lightweight Spacer Damper on bottom and top phases of the spans in this monopole designed system. For those spans where the line sags were exceptionally deep and the clearance between the phases was insufficient to provide a safe buffer, even with maximum galloping control, AR recommended the AR Spacer Twister. The Spacer Twister maintains separation between the phases, while guarding against conductor galloping.