Discussion: partial discharges in ellipsoidal and spheroidal voids

Danikas, M. G.; McAllister, I.W.; Crichton, G.C.; Pedersen, A.

doi:10.1109/14.85127

Cited by 19 publications

(7 citation statements)

References 6 publications

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“…This parameter defines the decay rate of free charges along the cavity surface or the insulation surface and is mainly dependent on the surface conductivity [9,[37][38][39][40][41]. A higher conductivity favours faster decay and reduces the availability of initial free electrons between two consecutive discharge events.…”

Section: Surface Time Constant τ Surmentioning

confidence: 99%

Diagnostic aspects of partial discharge measurement at very low frequency: a review

Morsalin

Das

2020

IET Science, Measurement &Amp; Technology

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Electrical insulation of high voltage (HV) power equipment/apparatus plays very important roles in the sound functioning of power systems. Examining the insulation condition through partial discharge (PD) measurements has considerable importance as the presence of PDs in any HV systems stands for a sign of defects and degradations in electrical insulation. Generally, the PD measurements are performed with a supply voltage of normal power frequency (PF-50/60 Hz). As an attractive alternative, the PD measurement with a very low frequency (VLF-1 Hz or lower) applied voltage has emerged as a powerful diagnostic tool. A PD event is a random physical process, it depends mostly on the availability of free electrons that triggers the PD and the presence of space charge usually originated after a discharge. As the discharge characteristics vary with the supply voltage frequency; thus, the existing interpretation knowledge at 50 Hz may or may not be directly applicable to other test frequencies, particularly in the VLF range. Therefore, to provide a general insight, this paper presents various diagnostic aspects of PD measurements, and at the end, various discharge sources (e.g., void, surface, and corona) and their behaviours under varying the test voltage frequencies are discussed in detail.

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Section: Surface Time Constant τ Surmentioning

confidence: 99%

Diagnostic aspects of partial discharge measurement at very low frequency: a review

Morsalin

Das

2020

IET Science, Measurement &Amp; Technology

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“…Instead, the PD transients are based on the induced charge concept which is summarized by equation (6) and related to equations (7) and (8). The absence of any change in capacitance during the discharge process can be opposed as follows:…”

Section: Change In Capacitance During Discharge Processmentioning

confidence: 99%

“…The induced charge concept has been criticized in [8] by Danikas, based on measurements presented in [9], but this criticism was opposed in the discussion of this paper [8] by McAllister by concluding (based on [6]) that the capacitance Manuscript received on 12 April 2008, in final form 6 August 2008. invoked in the model does not exist in reality. Further, the induced charge concept (as presented in [5]) has been modeled in PSpice in [10].…”

Section: Introductionmentioning

confidence: 95%

Partial discharges and associated transients: the induced charge concept versus capacitive modeling

Achillides

Georghiou

Kyriakides

2008

IEEE Trans. Dielect. Electr. Insul.

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Ensuring a reliable electric service to industrial, commercial and residential customers is becoming an important parameter for every electricity company due to the increased demand from the customers for less downtime, high productivity and reduced maintenance cost of machinery caused by unscheduled frequent interruptions due to underground power cable failures. The presence of partial discharges (PD) is one of the most prominent indicators of defects and ongoing degradation processes of electrical insulation. The capacitive network representation of the void (model) has long been used for the study of the transients generated by a breakdown void. As an alternative to the capacitive representation of the void (model) the induced charge concept has been introduced expressing strong criticism against the capacitance modeling of voids. This paper discusses and argues this criticism and exploits the potential and weakness of the classical capacitive representation of the voids from a theoretical point of view. Finally, a new capacitive model for voids is proposed based on the induced charge concept.

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“…The last term in (8) presents the probability that a single electron develops into an avalanche. Some investigations have concluded that this probability follows the Poisson-like distribution [19,20].…”

Section: Time Intervals Between Successive Pds Inmentioning

confidence: 99%

“…Due to the charge memory effect, PD behaviors in void are impacted by the waveform of applied voltage [5,6]. Though the void discharges under power frequency, dc and square ac voltages have been extensively studied [5,[7][8][9], few studies so far have been focused on discharges under impulse voltages especially under the oscillation impulse voltage. Under varying voltage gaseous void discharges show some different characteristics in terms of their occurrences, propagations and the statistic distribution [10].…”

Section: Introductionmentioning

confidence: 99%

Partial discharges in SF<sub>6</sub> gas filled void under standard oscillating lightning and switching impulses in uniform and non-uniform background fields

Ren

Dong

Yuan

et al. 2014

IEEE Trans. Dielect. Electr. Insul.

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Behaviors and characteristics of partial discharges in SF 6 gas filled void are investigated under oscillating lightning impulse voltage (OLI) and switching impulse voltage (OSI). The negative and positive PD sequences under impulses are described and analyzed under the applications of uniform and non-uniform background fields. Four types of discharge pulses in sequences are distinguished by their magnitudes, waveforms and time interval and well interpreted by a charge memory physic model. The distribution of PD points under OLI and OSI in normalized phase range (φ N , I m ) are proposed to describe the occurrence of PD under periodic oscillation impulses statistically. It is indicated that the discharges with low magnitudes are distributed in the relative large ranges of phase and the discharges with high magnitudes are mainly distributed in the relative narrow ranges of phase. By experimental results, the influences of the gas pressure and the void dimension ratio are studied and it is concluded that both the increases of these two factors could bring the obvious restrictions on PD activity under oscillating impulses.

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Discussion: partial discharges in ellipsoidal and spheroidal voids

Cited by 19 publications

References 6 publications

Diagnostic aspects of partial discharge measurement at very low frequency: a review

Diagnostic aspects of partial discharge measurement at very low frequency: a review

Partial discharges and associated transients: the induced charge concept versus capacitive modeling

Partial discharges in SF<sub>6</sub> gas filled void under standard oscillating lightning and switching impulses in uniform and non-uniform background fields

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