EoW November 2007

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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 [1] 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,’ 12 th 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 th International 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) Nolden, Fink, ‘Betriebsüberwachung 6. References

Figure 11 : Completely assembled temperature and strain monitoring system ▲

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

• 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 .

Figure 12 : Comparison between temperatures measured by the different systems ▲

Draka Comteq Germany GmbH & Co KG Bonnenbroicher Str 2-14 D-41238 Mönchengladbach Germany Email : info@draka.com Website : www.draka.com

Figure 13 : Correlation between the temperature and the force in the conductor ▲

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EuroWire – November 2007