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vibrations/ movements/ overloads

New trends on real time measurement on power lines : application to ampacity, aeolian vibrations and others. vibrations/ movements/ overloads. What is actual sag ?. Unpredicted problems may occur because of (CIGRE brochure) : variations in line construction strand settlement strain

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vibrations/ movements/ overloads

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  1. New trends on real time measurement on power lines :application to ampacity, aeolian vibrations and others WISMIG meeting, Arlington, USA, May 2008

  2. vibrations/ movements/ overloads WISMIG meeting, Arlington, USA, May 2008

  3. What is actual sag ? Unpredicted problems may occur because of (CIGRE brochure) : variations in line construction strand settlement strain Elastic strain conductor creep (plastic strain) inaccuracy of sag calculation methods Ice/wind loads ampacity of joint and clamps annealing of conductor use of high temperature conductor WISMIG meeting, Arlington, USA, May 2008

  4. Ampacity : what is it ? • Ampacity (=power transit reserve available), based on maximum sag information in real time The experience shows that : • ambient conditions are less constraining (98% of the time). An increased ampacity of the conductor depending on the actual weather condition is thus generally available. WISMIG meeting, Arlington, USA, May 2008

  5. Real time vs static rating • 90-98% of the time OHL can carry 10-30% higher load than static ratings (thermal limits) Real time conditions Conditions for Static rating e.g.: ambient 35°C Velocity 0.6 m/s Full solar radiation Wind speed Ambient temperature WISMIG meeting, Arlington, USA, May 2008

  6. Key information • A few% of time, static rating is risky because it is superior to actual rating Fixed rating Load Actual dynamic rating Potential clearance problems WISMIG meeting, Arlington, USA, May 2008

  7. Ampacity in real time: what for ? • Better usability of the lines (save investment, earn more money in inter-ties links,…) • Redirect load flow in case of « orange light » to avoid potential cascade failures • Tool against black-out WISMIG meeting, Arlington, USA, May 2008

  8. Existing systems WISMIG meeting, Arlington, USA, May 2008

  9. Dead-end span tension recordingmainly for ampacity • Tension recording (anchoring tower) (T. Seppa,USA, 1993). Belongs to NEXANS from 2007. WISMIG meeting, Arlington, USA, May 2008

  10. microsystems Base station or GSM/GPRS The new idea : AMPACIMON WISMIG meeting, Arlington, USA, May 2008

  11. Ampacimon – characteristics • Online monitoring system • You can place it where you want on the span • Based on an analysis of the line vibrations (0- 100Hz) • Autonomous A transformer allows Ampacimon to feed itself from the powerline • Measures and transmits power line accelerations An antenna emits towards a base station or a repeater GSM/GPRS soon available WISMIG meeting, Arlington, USA, May 2008

  12. Ampacimon already installed on 220 kV ELIA network WISMIG meeting, Arlington, USA, May 2008

  13. First results on 220 kV ELIA line. Sag/temperature evolution • Ambiant (10 m high), wind speed WISMIG meeting, Arlington, USA, May 2008

  14. Bayeux (Fr), 90 kV, installation on live line WISMIG meeting, Arlington, USA, May 2008

  15. How Ampacimon works ? for ampacity : • Ampacimon detect low frequencies (accelerometers) • Sag is deduced without the need of any other data • As frequency only is needed, not amplitude, we do not need calibration ! • Precision on sag depends on sampling frequency, actually around 2%. • Data transmitted by radio wave (soon by GSM/GPRS) to a base station WISMIG meeting, Arlington, USA, May 2008

  16. Typical signal analysis(ampacity) WISMIG meeting, Arlington, USA, May 2008

  17. Typical day outputs (ampacity) WISMIG meeting, Arlington, USA, May 2008

  18. How Ampacimon works ?for aeolian vibrations • Ampacimon detects all range of frequencies (2-100 Hz)(accelerometers) • Based on treatment (wave propagation), maximum wave amplitudes (and corresponding frequencies) are evaluated in any sample of about 20 s • Amplitude diagram are produced and life time established by extrapolation (Cigre method) WISMIG meeting, Arlington, USA, May 2008

  19. Typical aeolian vibrations measured by Ampacimon • As measured at Dead Water Fell site in UK (May 2006) • Estimated life time : 25 years in such environment WISMIG meeting, Arlington, USA, May 2008

  20. Bayeux (Fr) , example of record 15 minutes observation by Ampacimon WISMIG meeting, Arlington, USA, May 2008

  21. Sag-temperature as measured WISMIG meeting, Arlington, USA, May 2008

  22. Conclusions • Overhead lines are not Swiss watches !! • Real time measurement is a must for actual operation and control of power lines • Autonomous system needed • One good way is using in-span systems WISMIG meeting, Arlington, USA, May 2008

  23. Conclusions (continued) • Measurement In-span allows to measure actual ampacity and peak-to peak aeolian vibration amplitudes, extensible to any movements • Direct sag measurement is possible without need of calibration • Aeolian vibrations also recordable. Short time observations (few weeks) helps to quantify actual self damping. • Extension to high temperature cable possible but needs development and testing WISMIG meeting, Arlington, USA, May 2008

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