Sensitivity verification and application of UHF sensor for partial discharge measurement in high voltage power transformer

UHF method is one of the well-known PD measurements and has been applied widely to PD diagnostic system of gas insulated switchgears (GISs). Recently, UHF method is also being applied to power transformers. This paper presents the UHF sensor for PD diagnosis of power transformers. To measure the PD inside of a power transformer, the UHF sensor is mostly mounted inside the oil drain valve of exterior walls in a power transformer. However, the size of the oil drain valve is too small to design sensors which have sufficient sensitivity and wide-band. The proposed UHF sensor has a structure of multi-resonance for high sensitivity and wide-band (300~1500MHz) measurement. The computer simulation was used for evaluating the UHF sensor's performance. The sensitivity of the proposed UHF sensor was verified using simulated partial discharge sources in Laboratory and a 154kV power transformer. From experimental results, the proposed UHF sensor has enough high sensitivity performance to detect PD in power transformers.

[1]  Jae Ryong Jung,et al.  Development of the on-line iPDM system for the PD diagnosis for 25.8kV C-GIS , 2008, 2008 International Conference on Condition Monitoring and Diagnosis.

[2]  J.J. Smit,et al.  Sensitivity Check of Internal Sensor for Power Transformer Partial Discharge Measurements , 2006, 2006 IEEE 8th International Conference on Properties & applications of Dielectric Materials.

[3]  S. Tenbohlen,et al.  Performance Check and Sensitivity Verification for UHF PD Measurements on Power Transformers , 2007 .

[4]  Martin D. Judd,et al.  UHF and current pulse measurements of partial discharge activity in mineral oil , 2006 .

[5]  S. Tenbohlen,et al.  Partial discharge measurement in the ultra high frequency (UHF) range , 2008, IEEE Transactions on Dielectrics and Electrical Insulation.

[6]  M.D. Judd,et al.  Partial discharge monitoring for power transformer using UHF sensors. Part 2: field experience , 2005, IEEE Electrical Insulation Magazine.