SPECTRAL METHOD FOR LOCALIZATION OF MULTIPLE PARTIAL DISCHARGES IN DIELECTRIC INSULATION OF HYDRO-GENERATOR COILS: SIMULATION AND EXPERIMENTAL RESULTS
Keywords:Hydro-generator coils, method of diagnosis, partial discharges, spectral analysis
A methodology based on spectral analysis for localization of multiple partial discharges in dielectric region of hydro-generator coils is proposed. This pinpointing of multiple discharges aims to provide means for performing diagnosis of insulating regions of the coil. A numerical model of the structure was developed by using the finite-difference time-domain method (FDTD-3D) to solve Maxwell's equations. Transient voltage associated with partial discharges that occurs at different positions of the coil is calculated at specific point and its spectrum is used to perform the diagnosis. Transient numerical results are validated by comparison with measurements published in literature. In 90% of simulations, accurate estimates of simultaneous discharges location were obtained. Physical phenomena allowing the development of the methodology are assessed numerically and experimentally. Finally, a localized artificial PD injection schema is proposed.
International Conference on Power Electronics, Machines and Drives (PEMD), pp. 1-6, 2012.
 J. C. Akiror, A. Merkhouf, C. Hudon and P. Pillay, “Consideration of design and operation on rotational flux density
distributions in hydro-generator stators”, International Conference on Electrical Machines (ICEM), pp. 93-99, 2014.
 W. Wang, C. R. Li, W. Li, L. Liu, Z. Wang, and L. Ding, “Pattern recognition of single and composite partial discharge
on generator stators”, Annual Report Conference on Electrical Insulation and Dielectric Phenomena, pp. 335-339, 2001.
 D. Wenzel, H. Borsi and E. Gockenbach. “Partial discharge recognition and localization on transformers via fuzzy
logic”, Conference Record of the IEEE International Symposium on Electrical Insulation, pp. 233-236, 1994.
 S. Birlasekaran, “Identification of the type of partial discharges in an operating 16kV/250 MVA generator”, Conference
on Electrical Insulation and Dielectric Phenomena, Annual Report. pp. 559-562, 2003.
 A. Kheirmand, M. Leijon, and S. M. Gubanski, “Advances in online monitoring and localization of partial discharges in
large rotating machines”, IEEE Transactions on Energy Conversion, 19 (1), pp.53-59, March 2004.
 R. Bozzo, C. Gemme, F. Guastavino, and G. Guerra, “Localization of partial discharge sites on power generator bars by
means of ultrasonic measurements”, IEEE lnstumentation and Measurement Technology Conference, pp. 658-663,
 H. R. Mirzaei, A. Akbari., E. Gockenbach, M. Zanjani, and K. Miralikhani, “A novel method for ultra-high-frequency
partial discharge localization in power transformers using the particle swarm optimization algorithm”, IEEE Electrical
Insulation Magazine, 29 (2), pp. 26-39, 2013.
 S. Biswas, C. Koley, B. Chatterjee, and S. Chakravorti, “A methodology for identification and localization of partial
discharge sources using optical sensors”, IEEE Transactions on Dielectrics and Electrical Insulation, 19 (1), pp.18-28,
 S. M. Hoek, A. Kraetge, O. Kessler, and U. Broniecki, “Time-based partial discharge localization in power transformers
by combining acoustic and different electrical methods”, International Conference on Condition Monitoring and
Diagnosis (CMD), pp. 289-292, 2012.
 Institute of Electrical and Electronics Engineers, “IEEE Trial-Use Guide to the Measurement of Partial Discharges in
Rotating Machinery”, IEEE Std. 1434 , 2000.
 Institute of Electrical and Electronics Engineers, “Guide to Measurement of Partial Discharge in Rotating Machinery”,
IEEE Std 1434, 2000.
 F. T. Ulaby, Electromagnetics for Engineers, Prentice Hall, 2005.
 M. N. O. Sadiku, Elements of Electromagnetics, Oxford Series in Electrical and Computer Engineering, 2000.
 Siemens, “Electrical datasheet: U.H.E Coaracy Nunes–Gerador de Salient Poles 1DH7139-3WF24-Z”, 1997.
 R. M. S. de Oliveira and C. Sobrinho, “Computational environment for simulating lightning strokes in a power
substation by Finite-Difference Time-Domain Method”, IEEE Transactions on Electromagnetic Compatibility, 51 (4),
pp.995-1000, Nov. 2009.
 O. Lesaint, T. Lebey, S. Dinculescu, H. Debruyne, and A. Petit, “Propagation of fast PD signals within stator bars
performance and limitations of a high frequency monitoring system”, Proceedings of the 7th International Conference
on Properties and Applications of Dielectric Materials, pp. 1112-1115, 2003.
 Z. Liu, T. R. Blackburn, B. T. Phumg, and R. E. James, “Detection of partial discharge in solid and liquid insulation
with an electric field sensor”, Proceedings of International Symposium on Electrical Insulating Materials, in
conjunction with Asian International Conference on Dielectrics and Electrical Insulation and the 30th Symposium on
Electrical Insulating Materials, pp. 661-664, 1998.
 A. Taflove, and S. Hagness, Computational Electrodynamics: The Finite-Difference Time-Domain Method, Artech
 S. R. Campbell, G. C. Stone, and H. G. Sedding, “Application of pulse width analysis to partial discharge detection”,
IEEE International Symposium on Electrical Insulation, pp. 345-348, 1992.
 G. C. Stone, H. G. Sedding, N. Fujimoto, and J. M. Braun, “Practical Implementation of Ultrawideband Partial
Discharge Detectors”, IEEE Transactions on Electrical Insulation, 27 (1), pp. 70-81, 1992.
 B. M. Oliver, “Directional Electromagnetic Couplers”, Proceedings of the Institute of Radio Engineers, pp. 1686-1694,