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

ULg : Pr. J.L. Lilien WISMIG meeting, Arlington, USA, May 2008 vibrations/ movements/ overloads

ULg : Pr. J.L. Lilien WISMIG meeting, Arlington, USA, May 2008 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

ULg : Pr. J.L. Lilien WISMIG meeting, Arlington, USA, May 2008 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.

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

ULg : Pr. J.L. Lilien WISMIG meeting, Arlington, USA, May 2008 Key information A few% of time, static rating is risky because it is superior to actual rating LoadActual dynamic rating Fixed rating Potential clearance problems

ULg : Pr. J.L. Lilien WISMIG meeting, Arlington, USA, May 2008 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

ULg : Pr. J.L. Lilien WISMIG meeting, Arlington, USA, May 2008 Existing systems

ULg : Pr. J.L. Lilien WISMIG meeting, Arlington, USA, May 2008 Dead-end span tension recording mainly for ampacity Tension recording (anchoring tower) (T. Seppa,USA, 1993). Belongs to NEXANS from 2007.

ULg : Pr. J.L. Lilien WISMIG meeting, Arlington, USA, May 2008 The new idea : AMPACIMON microsystems Base station or GSM/GPRS

ULg : Pr. J.L. Lilien WISMIG meeting, Arlington, USA, May 2008 Ampacimon – characteristics 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 Online monitoring system Based on an analysis of the line vibrations (0- 100Hz) You can place it where you want on the span

ULg : Pr. J.L. Lilien WISMIG meeting, Arlington, USA, May 2008 Ampacimon already installed on 220 kV ELIA network

ULg : Pr. J.L. Lilien WISMIG meeting, Arlington, USA, May 2008 First results on 220 kV ELIA line. Sag/temperature evolution Ambiant (10 m high), wind speed

ULg : Pr. J.L. Lilien WISMIG meeting, Arlington, USA, May 2008 Bayeux (Fr), 90 kV, installation on live line

ULg : Pr. J.L. Lilien WISMIG meeting, Arlington, USA, May 2008 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

ULg : Pr. J.L. Lilien WISMIG meeting, Arlington, USA, May 2008 Typical signal analysis (ampacity)

ULg : Pr. J.L. Lilien WISMIG meeting, Arlington, USA, May 2008 Typical day outputs (ampacity)

ULg : Pr. J.L. Lilien WISMIG meeting, Arlington, USA, May 2008 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)

ULg : Pr. J.L. Lilien WISMIG meeting, Arlington, USA, May 2008 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

ULg : Pr. J.L. Lilien WISMIG meeting, Arlington, USA, May 2008 Bayeux (Fr), example of record 15 minutes observation by Ampacimon

ULg : Pr. J.L. Lilien WISMIG meeting, Arlington, USA, May 2008 Sag-temperature as measured

ULg : Pr. J.L. Lilien WISMIG meeting, Arlington, USA, May 2008 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

ULg : Pr. J.L. Lilien WISMIG meeting, Arlington, USA, May 2008 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