Spectral Power Analysis of Partial Discharges Waveforms During Electrical Tree Growth Under Different Excitation Frequencies
Electrical trees are the main mechanism of failure in solid polymeric insulation. Their growth is associated to partial discharge (PD) activity. Measuring and analyzing PDs during tree growth is crucial for the insulation condition assessment and thus, the risk of failure of power equipment. Here, PD pulse waveforms are analyzed using power ratios maps. The aim of the study is to evaluate the ability of power ratio maps to determine the state of progression of electrical trees. Electrical trees were grown in epoxy resin samples at different frequencies, while PDs were measured using very-high frequency (VHF) and ultra-high frequency (UHF) techniques. The progression of the tree was observed using an optical camera and it was correlated with PD data. The results showed that power ratio maps obtained from VHF and UHF signals yield similar patterns. Especially in VHF, it was observed that the centroids of the clusters associated to each stage of tree-growth moved with tree-progression. PDs at the beginning of tree-growth were located at the top-right of power maps, while in more advanced stages, they were located more to the bottom-center of the maps. This means that the PD pulse waveform had higher frequency content in the beginning than in the end of tree growth. In base of this initial results, it is concluded that power ratio maps are sensitive to the state of growth of electrical trees, and thus, can be used for assessing the risk of failure of insulation subjected to electrical treeing degradation mechanism.
KeywordsPartial discharges Electrical trees Power ratio maps
RS acknowledges funding support from Chilean Research Council (CONICYT) under FONDECYT project Nº 11181177. JA acknowledges support from FONDECYT project Nº 11160115. The authors also thank Universidad Técnica Federico Santa María for the grant PI_L_18_19.
- 2.Schurch, R., Donoso, P., Aguirre, P., Cardenas, O., Zuniga, M., Rowland, S.M.: Electrical tree growth and partial discharges analyzed by fractal and correlation dimensions. In: IEEE Conference on Electrical Insulation and Dielectric Phenomenon (CEIDP), pp. 785–788 (2017)Google Scholar
- 3.Mohan, N., Undeland, T.M.: Power Electronics: Converters, Applications, and Design. Wiley, Hoboken (2007)Google Scholar
- 4.IEEE 400.2-2013: IEEE Guide for Field Testing of Shielded Power Cable Systems Using Very Low Frequency (VLF) (less than 1 Hz) (2013)Google Scholar
- 5.Dao, T., Phung, B.T., Blackburn, T., Nguyen, H.V.P.: A comparative study of partial discharges under power and very low frequency voltage excitation. In: IEEE Conference on Electrical Insulation and Dielectric Phenomenon (CEIDP), pp. 164–167 (2014)Google Scholar
- 7.Chalashkanov, N.M., Dodd, S.J., Dissado, L.A., Fothergill, J.C.: Pulse sequence analysis on PD data from electrical trees in flexible epoxy resins. In: IEEE Conference on Electrical Insulation and Dielectric Phenomenon (CEIDP), pp. 776–779 (2011)Google Scholar
- 9.Schurch, R., Orellana, L., Donoso, P., Ardila-rey, J., Montana, J.: Pulse waveform, phase-resolved and pulse sequence analysis of partial discharges during electrical tree growth in epoxy resin. In: International Symposium on High Voltage Engineering (ISH) (2017)Google Scholar
- 12.Gao, Y., Deng, Y.D., Du, B.X., Li, S.W., Wang, N.: Electrical treeing behavior in XLPE under kHz-AC voltage. In: IEEE International Conference on Dielectrics, vol. 2, pp. 724–727 (2016)Google Scholar
- 13.Ildstad, E., Fauskanger, K., Hølto, J.: Electrical treeing from needle implants in XLPE during very low frequency (VLF) voltage testing. In: IEEE International Conference on Solid Dielectrics (ICSD), pp. 800–803 (2013)Google Scholar
- 15.Martínez-Tarifa, J.M., Ardila-Rey, J.A., Robles, G.: Automatic selection of frequency bands for the power ratios separation technique in partial discharge measurements: part I, fundamentals and noise rejection in simple test objects. IEEE Trans. Dielectr. Electr. Insul. 22(4), 2284–2292 (2015)CrossRefGoogle Scholar
- 16.IEC-60270:2000: High-voltage test techniques - Partial discharge measurements (2000)Google Scholar