Spectral Power Analysis of Partial Discharges Waveforms During Electrical Tree Growth Under Different Excitation Frequencies

Partial Discharge Electrical Tree Growth Identification by Means of Waveform Source Separation Techniques

“…Electrical tree growth was characterized by both the waveform of PD pulses, measured through the entire tree growth, and the length of the electrical trees as they grew, extracted from pictures. Tree length is widely used for electrical treeing characterization [24], [26], and it is considered an appropriate parameter to estimate the remaining insulation life, since the final breakdown occurs soon after the tree crosses the insulation [34]- [35]. The waveform of PDs and treeing pictures were synchronized for adequate correlation.…”

“…Furthermore, these separation techniques have demonstrated that the shape and position of the clusters associated with any type of source may vary significantly if there is any change in the electrical parameters of the measurement circuit, which also includes the test object [9]- [10], [12]- [13]. Thus, it is expected that these techniques could be useful in both the diagnosis of insulation containing electrical trees given their dynamics, and the difficult task of evaluating the growth of trees [21]- [26]. Nevertheless, only one of these techniques (SPCT) has been explored so far in terms of its capability to determine the state of progression of electrical trees [20], [26].…”

“…Thus, it is expected that these techniques could be useful in both the diagnosis of insulation containing electrical trees given their dynamics, and the difficult task of evaluating the growth of trees [21]- [26]. Nevertheless, only one of these techniques (SPCT) has been explored so far in terms of its capability to determine the state of progression of electrical trees [20], [26]. The findings of that research showed that power ratio maps (SPCT) are sensitive to the growth of electrical trees, presenting a displacement of the clusters in a 2D map as the tree progressed.…”

“…Such is the case of renewable energies just as solar and wind, which provide an important income of pollution in power networks [27]. On the other hand, very low frequency (VLF, typically 0.1 Hz) is currently used for diagnostic testing of power cables [4] and new methods of PD analysis are required for VLF testing [5], [26]. Few and recent studies have considered PD source separation maps for electrical tree characterization at different frequencies [24], [26].…”

“…On the other hand, very low frequency (VLF, typically 0.1 Hz) is currently used for diagnostic testing of power cables [4] and new methods of PD analysis are required for VLF testing [5], [26]. Few and recent studies have considered PD source separation maps for electrical tree characterization at different frequencies [24], [26]. However, they have not exploited the techniques addressed in this paper, which have proven to be useful in applications involving both high frequency and low frequency signals [28], and can be complemented with several measurement systems like VHF or UHF [9], [13], [26].…”