EoW November 2007

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EuroWire – November 2007 78
english
• replacement of the existing extension
links by the ones with the FBG sensors
• installation of the weather station on
the tower top
• the set-up of the signal processing unit
and the computer
The first three items had to be realised
within the 4 hour power outage. With
the separator completely assembled on
the ground including all splice connections
to all sensors, the outage time was
sufficiently long to finish the work.
The following figures give a picture of
the installation: Figure 9 shows the fully
assembled separator including both
jumper cables and clevis straps with strain
sensors. Details of the separator top with
the cable entries and the strain sensors
is given in Figure 10. The final view of the
fully installed temperature and strain
monitoring hardware is shown in Figure 11.
4.Measurement results
One objective for the field installation was
to compare the temperature measurement
of the presented system with a system
using a DTS on the same power line.
Data from both temperature monitoring
systems were continuously recorded
every 15 minutes and compared with
the temperature data from the weather
station. Figure 12 shows the comparison
for one day, exemplarily.
Although there is a temperature difference
between the systems, the correlation
is very good. This behaviour which
was observed throughout the whole
measurement period of several months
justifies the assumption that a local
temperature measurement system using
FBG sensors in the jumper can predict the
temperature behaviour of a whole link.
Another example from the same day
presents the correlation between the
temperature measured with the FBG
sensor and the force in the conductor
measured with strain sensor (Figure 13).
Although the force in the conductor is
not only influenced by the conductor
temperature, the general expected
behaviour is clearly visible: With increasing
temperature, the conductor’s elongation
increases and hence, the force goes down,
and vice versa.
The remaining data, eg wind direction
and speed, humidity and electrical current
were all recorded but as their relationship
with temperature and conductor strain is
rather complex, a detailed analysis is still
ongoing.
5. Conclusions
This demonstrates that a power line
monitoring system based on FBG sensors
implemented in the jumper is a highly
accurate, reliable and cost-efficient system.
The advantages of this monitoring system,
its ease of installation, the short power
outage time for assembly, its modularity
and upgradability makes it an excellent
alternative to other systems, eg distri-
buted temperate measurement based on
Raman scattering. n
6. References
[1] Nolden, Fink, ‘Betriebsüberwachung von
Freileitungen mit intrischer Temperaturmessung,’
ew Jg 102Heft 8, pp 18-19 (2003)
[2] Kashyap, ‘Photosensitive Optical Fibers: Devices
and Applications,’ Optical Fiber Technology 1,
pp 17-34 (1994)
[3] Meltz, Morey, Glenn, ‘Formation of Bragg gratings
in optical fibers by a transverse holographic
method,’ Optics Letters Vol 14, No 15, pp 823-825
(1989)
[4] Klink, Meissner, Nowak, Slowik, ‘Strain Monitoring
at a Prestressed Concrete Bridge,’ 12th International
Conferenceon Optical Fiber Sensors, Technical
Digest, pp 408-411 (1997)
[5] Peupelmann, Meissner, ‘Applications and Field
Tests of a Fibre Bragg Grating Sensor System,’
13 thInternational Conference on Optical Fiber
Sensors, Technical Digest, pp 470-473 (1999)
[6] EN 50182, ‘Conductors for Overhead Lines – Round
Wire Concentric Lay Stranded Conductors,’(2001)
[7] Girbig, Jansen, Hög, ‘New Generation of Optical
Phase Conductor Accessories for Different Voltage
Levels,’ ROC&C’2003, IEEE section Mexico (2003)
[8] Girbig, Jansen, Hög, ‘Advanced OPPC Accessories
for Medium and High Voltage Applications,’
WireChina 2004 Technical Conference, Shanghai
(2004)
[9] Girbig, Nothofer, ‘Enhanced OPPC Accessories
for Applications on 245kV High Voltage Power
Lines,’ International Wire and Cable Symposium
Proceedings 2004, pp 570-574 (2004)
[10] Girbig, Bernon, Chaussecourte, Le Gac, ‘OPPC
Solutions for 63kV, 90kV and 225kV Power
Lines,’ International Wire and Cable Symposium
Proceedings 2005, pp 570-574 (2005)
Draka Comteq Germany
GmbH & Co KG
Bonnenbroicher Str 2-14
D-41238 Mönchengladbach
Germany
Email:
Website:
Figure 11: Completely assembled temperature and strain monitoring system ▲
Figure 12: Comparison between temperatures
measured by the different systems
▲
Figure 13 : Correlation between the temperature
and the force in the conductor
▲