september 2005 pr. j.l. lilien cable dynamics 2005 charleston sc(usa) overhead power lines real time...

September 2005Pr. J.L. Lilien

CABLE DYNAMICS 2005Charleston SC(USA)

OVERHEAD POWER LINES REAL TIME MONITORING : A FUTURE TREND ?

August 2003: Black-Out in USA initiated by ampacity problem



The problems

• Ampacity (power transit reserve available), based on maximum sag possible

• Vibration/movement monitoring (any kind)• Ageing evaluation/predictive maintenance• Load flow redirection in case of potential

problems (thunderstorm, icing,..)

• Market Liberalisation and « nimby » symptom force to operate Lines at different conditions than they were originally designed for



Real time monitoring : Targets ?

• National dispatching (informations in due time for bulk power lines)

• Utilities and national transmission network management (trouble shooting, risk evaluation with vibrations, ageing, etc..)

• Cable manufacturers (to evaluate (new) cable behaviour, like HT, self-damping, etc.)

• Scientific world (to follow up in real time some phenomena to better understand/study)



Ampacity

• (courtesy PTI, Dale Douglas)



Vibrations



Gusty wind, icing, etc..

-16

-14

-12

-10

-8

4 6 8 10 12 14 16 18

Y, m

Z, m Aero Z

-16

-14

-12

-10

-8

4 6 8 10 12 14 16 18

Y, m

Z, m ASTER

U = 30 m/s

Y X

Z



Available systems• Vibration recorders (near suspension clamp)• Two examples (Pavlica (Hydroquébec) and VIBREC (Sefag))



Sag measurement

• From the tower



In span current/wind/solar and temperature measurement

• Multisensor device (Davis, USA, 1994)



Dead-end span recording

• Tension recording (anchoring tower) (T. Seppa,USA, 1993)



In span measurement

• Temperature sensor SAW (TUD, Pr Hinrichsen), presented at CIGRE 2004



In span multisensors

• Multisensors (Protura, NO, 2004)



In span vibrations by fiber optics

• Fiber Bragg grating (Sintef, NO, 2004)



In span autonomous multisensors

• In span autonomous multisensor (Ulg, Belgium, 2004)



Ampacimon on 220 kV line in Belgium



Typical signal analysis



Typical day outputs (tension, tower stiffness)

Evolution de la traction dans le câble le 03/07/2004 en fonction de l'heure

4,5

4,55

4,6

4,65

4,7

4,75

4,8

4,85

4,9

4,95

5

0 5 10 15 20

heure de la mesure (h)

tra

ctio

n (

kN)

traction dans le câble (kN)

Evaluation de la raideur des ancrages sur 6 mesures

0,00E+00

5,00E-01

1,00E+00

1,50E+00

2,00E+00

2,50E+00

3,00E+00

3,50E+00

4,00E+00

4,50E+00

5,00E+00

0 5 10 15 20

heure de la mesure (h)

raid

eur

(10^

5N/m

)

raideur des pylones (10^5N/m)



Findings (70 kV line)

• Actual sag much larger (+94% in sag) than « as built » conditions (of course extrapolated to actual temperature conditions)

• Difficulties in the definition of conductor temperature, direct sag evaluation is extremely helpful

• Not yet any high frequency vibrations observed (one year of continuous recording)



Challenges for in-span systems

• Low weight (not to disturb vibrations)

• Autonomous (extract power from the line at a non constant load)

• Manage corona problem (antenna !)

• Manage strong transients (lightning, short-circuit) with systems reactive to a few volts



Challenges for in-span systems

• Data management (locally, base station) to limit transmitted informations

• The distance between system and base station

• Synchronism between some informations will be sometimes needed



Global network approach

• Transmission line level : in span systems• License-free HF radio wave transmission to

base station (few km from one system)• Base station linked to Internet• Secure web site with intelligent data analysis• Operator’s console digest informations

transferred• Availability of data storage for any purpose• Combine electrical and mechanical protection

approach



In span system maintenance

• In span system may be tailored from the ground in its vicinity and new software may be stored without direct link

• Diagnostic may be obtained from the ground, some systems may be installed in sleep mode without global disturbance

• Information may be transmitted from one system to another (with possible jump)

• Inside system, some redundance is used for low cost material



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



Conclusions (continued)

• In-span allows to measure ampacity, movement (thunderstorm, ice shedding), vibrations

• Direct sag measurement is possible

• Challenges : robustness, EMC, low weight

• Competition open including global network system approach



Acknowledgment

• The Ampacimon project has been developed under the sponsorship of the government of the « Communauté Française de Belgique », ARC project 03-08/296.

• We kindly acknowledge the three teams of research involved :

• Microsystems : Pr J. Destiné, Ir. J-M. Feiereisen, O. Fontaine

• Spatial research center : Pr C. Jamar, Ir. L. Renson, J-M. Gillis

• Transmission and Distribution of Electrical Energy : Pr J.L. Lilien, Ir. S. Guérard, B. Godard

september 2005 pr. j.l. lilien cable dynamics 2005 charleston sc(usa) overhead power lines real time...

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