Partial discharges in epoxy resin voids and the interpretational possibilities and limitations of Pedersen's model

Danikas, M. G.; Adamidis, G.

doi:10.1007/bf01245959

Cited by 23 publications

(7 citation statements)

References 27 publications

(28 reference statements)

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“…Figure 3 shows sample traces corresponding to three different sources: a neutron event, an alpha-particle event, and a microdischarge from the proportional counter. Microdischarges are electronic artifacts originating from current leakage in the bias voltage breakdown applied to the counter [29,30,31]. To determine the pulse height of the waveform, one first removes the baseline offset by subtracting off the average of the first few hundred samples of the trace, well before the pulse onset.…”

Section: Analysis Methodsmentioning

confidence: 99%

Event identification in 3He proportional counters using risetime discrimination

Langford

Bass

Beise

et al. 2013

Nuclear Instruments and Methods in Physics Research Section A:

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We present a straightforward method for particle identification and background rejection in 3 He proportional counters for use in neutron detection. By measuring the risetime and pulse height of the preamplifier signals, one may define a region in the risetime versus pulse height space where the events are predominately from neutron interactions. For six proportional counters surveyed in a low-background environment, we demonstrate the ability to reject alpha-particle events with an efficiency of 99%. By applying the same method, we also show an effective rejection of microdischarge noise events that, when passed through a shaping amplifier, are indistinguishable from physical events in the counters. The primary application of this method is in measurements where the signal-to-background for counting neutrons is very low, such as in underground laboratories.

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Section: Analysis Methodsmentioning

confidence: 99%

Event identification in 3He proportional counters using risetime discrimination

Langford

Bass

Beise

et al. 2013

Nuclear Instruments and Methods in Physics Research Section A:

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“…PDs usually occur as a result of the various defects, as described above. PDs in EMs cause typical patterns, the analysis of which can identify the origin of different PDs [18][19][20][21]. PDs can be categorized as [11]:…”

Section: Pds On Emsmentioning

confidence: 99%

“…Eight different water droplet setups were chosen (Figures [18][19][20][21], which one by one, were positioned on the sample surface of the epoxy resin. Eight different water conductivies were used, from 1.4 µS/cm to 10,000 µS/cm, in order to investigate how they affect the PD.…”

Section: Effect Of Humidity On Pdsmentioning

confidence: 99%

Investigation of Factors Affecting Partial Discharges on Epoxy Resin: Simulation, Experiments, and Reference on Electrical Machines

et al. 2021

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In Power Systems, Synchronous Generators (SGs) are mostly used for generating electricity. Their insulation system, of which epoxy resin is a core component, plays a significant role in reliable operation. Epoxy resin has high mechanical strength, a characteristic that makes it a very good material for reliable SG insulation. Partial Discharges (PDs) are a constant threat to this insulation since they cause deterioration and consequential degradation of the aforementioned material. Therefore, it is very important to detect PDs, as they are both a symptom of insulation deterioration and a means to identify possible faults. Offline and Online PDs Tests are described, and a MATLAB/Simulink model, which simulates the capacitive model of PDs, is presented in this paper. Moreover, experiments are carried out in order to examine how the flashover voltage of epoxy resin samples is affected by different humidity levels. The main purpose of this manuscript is to investigate factors, such as the applied voltage, number, and volume of water droplets and water conductivity, which affect the condition of epoxy resin, and how these are related to PDs and flashover voltages, which may appear also in electrical machines’ insulation. The aforementioned factors may affect the epoxy resin, resulting in an increase in PDs, which in turn increases the overall Electrical Rotating Machines (EMs) risk factor.

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“…During ageing, an oxidized layer containing carbonyl radicals (=CO) appear at the cavity surface, which modifies its conductive characteristics, affecting indeed the PD inception and extinction magnitude, the electric field distribution and streamer landing pattern [32]. The non-uniform deposition of by-products cause that some areas are prone to experience intensive bombardment [38]. In epoxy specimens, the oxidation process is dependent on the curing process because it has been shown that when anhydride hardener is used it reacts with most of the oxygen leaving an atmosphere that is 80-98% nitrogen.…”

Section: Degradation Of Polymeric Materials Induced By Pds In Cavitiesmentioning

confidence: 99%

“…Taking into account theoretical and experimental studies [38,51], it is assumed that PDs in spherical cavities can incept treeing, these being the last stage of the aging process before breakdown. Once the electrical tree is incepted, i.e., the first tree channel has a length enough for develop self-sustained PDs independent from those at the cavity, electrical tree continues propagating via a physical degradation mechanism [31,41].…”

Section: Calculation Of the Degradation Induced By Pds And Life Estimation Approachmentioning

confidence: 99%

A Study on the Life Estimation and Cavity Surface Degradation Due to Partial Discharges in Spherical Cavities within Solid Polymeric Dielectrics Using a Simulation Based Approach

Rodríguez‐Serna

Albarracín‐Sánchez

2021

Polymers

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Partial Discharges (PD) in cavities are responsible for the greatest ageing rate in polymeric solid dielectrics due to chemical and physical deterioration mechanisms activated by the charge carriers, Ultra Violet (UV) radiation and local temperature rising during PDs activity. From the above, it is necessary to develop prognosis tools based on PDs measurements as diagnostic quantities in order to infer the time-to-breakdown, life, of solid dielectrics for improving the reliability of electrical assets, especially in current applications where they are subject to great electrical stresses in voltage frequency and magnitude. In this paper, the degradation in polymeric materials induced by PDs in cavities is briefly discussed from a phenomenological point of view, and then it is quantitatively evaluated using a simulation-based approach and a new proposed damage function. The time-to-breakdown calculated from simulations exhibits good agreement when compared with experimental measurements. Additionally, an analysis on the effect of the magnitude and frequency of the applied voltage on the degradation rate is also presented and the effectiveness of a degradation indicator, proposed by other authors, is evaluated under different stress conditions.

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Partial discharges in epoxy resin voids and the interpretational possibilities and limitations of Pedersen's model

Cited by 23 publications

References 27 publications

Event identification in 3He proportional counters using risetime discrimination

Event identification in 3He proportional counters using risetime discrimination

Investigation of Factors Affecting Partial Discharges on Epoxy Resin: Simulation, Experiments, and Reference on Electrical Machines

A Study on the Life Estimation and Cavity Surface Degradation Due to Partial Discharges in Spherical Cavities within Solid Polymeric Dielectrics Using a Simulation Based Approach

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