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Front. Inform. Technol. Electron. Eng.  2011, Vol. 12 Issue (4): 345-350    DOI: 10.1631/jzus.C1000126
    
Detection and location of partial discharge in cast-resin dry-type transformers using a waveguide and a new acoustic emission sensor pair design
Ching-chau Su*, Ya-wen Tang, Cheng-chi Tai, Jiann-fuh Chen
Department of Electrical Engineering, National Cheng Kung University, Taiwan 70101, Tainan City
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Abstract  The acoustic emission (AE) method could be used to detect and locate partial discharges (PD) in cast-resin dry-type transformers. However, due to the high sound attenuation in the filled epoxy, the signal is prone to interference from external noises and thus, in practice, there is little possibility of detecting PD. In this study, two techniques were developed to alleviate the shortcomings of the AE method. First, a waveguide is installed on the high-voltage (HV) windings, so that the acoustic signals of PD will propagate to the AE sensors that are installed on both terminals of the waveguide. The location of the winding that has PD can then be detected from the difference in arrival time of the acoustic signals. Test results indicate that the waveguide technique is able to enhance the safety of a measurement system and offers the advantages of easy installation and higher flexibility. Second, a specially designed AE sensor pair is used to distinguish whether acoustic signals are generated by PD inside the HV winding or by the corona outside the transformers. Using these two techniques of waveguide and AE sensor pair not only greatly improves sensitivity but also increases the reliability of the measurement system. Practical test results show that the new techniques can be used to locate precisely the PD in HV windings.

Key wordsPartial discharge      Acoustic emission      Cast-resin dry-type transformer      Waveguide      Acoustic emission sensors     
Received: 01 May 2010      Published: 11 April 2011
CLC:  TM403.2  
Cite this article:

Ching-chau Su, Ya-wen Tang, Cheng-chi Tai, Jiann-fuh Chen. Detection and location of partial discharge in cast-resin dry-type transformers using a waveguide and a new acoustic emission sensor pair design. Front. Inform. Technol. Electron. Eng., 2011, 12(4): 345-350.

URL:

http://www.zjujournals.com/xueshu/fitee/10.1631/jzus.C1000126     OR     http://www.zjujournals.com/xueshu/fitee/Y2011/V12/I4/345


Detection and location of partial discharge in cast-resin dry-type transformers using a waveguide and a new acoustic emission sensor pair design

The acoustic emission (AE) method could be used to detect and locate partial discharges (PD) in cast-resin dry-type transformers. However, due to the high sound attenuation in the filled epoxy, the signal is prone to interference from external noises and thus, in practice, there is little possibility of detecting PD. In this study, two techniques were developed to alleviate the shortcomings of the AE method. First, a waveguide is installed on the high-voltage (HV) windings, so that the acoustic signals of PD will propagate to the AE sensors that are installed on both terminals of the waveguide. The location of the winding that has PD can then be detected from the difference in arrival time of the acoustic signals. Test results indicate that the waveguide technique is able to enhance the safety of a measurement system and offers the advantages of easy installation and higher flexibility. Second, a specially designed AE sensor pair is used to distinguish whether acoustic signals are generated by PD inside the HV winding or by the corona outside the transformers. Using these two techniques of waveguide and AE sensor pair not only greatly improves sensitivity but also increases the reliability of the measurement system. Practical test results show that the new techniques can be used to locate precisely the PD in HV windings.

关键词: Partial discharge,  Acoustic emission,  Cast-resin dry-type transformer,  Waveguide,  Acoustic emission sensors    
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