Comparative Analysis versus Frequency of Inception Voltage of Partial Discharges Phenomena and Breakdown Strength, in Support of Quality Assessment of Insulating Materials

2010 ◽  
Vol 437 ◽  
pp. 584-588
Author(s):  
Romeo Cristian Ciobanu ◽  
Cristina Schreiner
Keyword(s):  
Comparative Analysis ◽  
Quality Assessment ◽  
Measurement Technique ◽  
Breakdown Strength ◽  
Partial Discharge ◽  
Partial Discharges ◽  
Insulating Materials ◽  
Complementary Method ◽  
Inception Voltage

The broadband Partial Discharge (PD) measurement technique may be considered more accurate than a simple breakdown test and admitted as a complementary method for characterizing the quality of porous/fibrous and composite insulating materials. It should be taken into account especially at higher frequencies, when the risk of breakdown occurrence becomes greater in time, due to the local thermal aspects.

scholarly journals Foreign Inclusions, Enclosed Cavities, Partial Discharge Models and Discharge Energy: A Short Review Regarding Solid Dielectrics and Composite Insulating Systems

2019 ◽  
Vol 9 (5) ◽  
pp. 4659-4666 ◽  
Author(s):  
M. Danikas ◽  
S. Morsalin
Keyword(s):  
Partial Discharge ◽  
Short Review ◽  
Partial Discharges ◽  
Discharge Energy ◽  
Insulating Materials ◽  
Discharge Parameters ◽  
Solid Dielectrics ◽  
The Relationship ◽  
Inception Voltage

Partial discharges in cavities are one of the main reasons of breakdown of insulating materials and insulating systems in general. The present paper aims at commenting some aspects of the relation between partial discharges and insulation damage. Some basic models explaining the workings and impacts of discharges in cavities are discussed. Discussions about the possibility of damage in the presence of multiple cavities as well as of the risks of minute discharges and/or charging phenomena below the so-called inception voltage are conducted. It is remarked that the question of the relationship between discharge parameters and insulation damage is still an important one, especially for composite insulating systems.

scholarly journals Partial Discharges in Cavities and their Connection with Dipoles, Space Charges, and Some Phenomena Below Inception Voltage

2020 ◽  
Vol 10 (4) ◽  
pp. 5869-5874
Author(s):  
G. E. Vardakis ◽  
M. Danikas ◽  
A. Nterekas
Keyword(s):  
Charge Distribution ◽  
Partial Discharge ◽  
Electromagnetic Theory ◽  
Partial Discharges ◽  
Charge Dynamics ◽  
Space Charges ◽  
Discharge Activity ◽  
Electric Dipoles ◽  
Inception Voltage

This paper tries to relate Pedersen’s model on partial discharges and work carried out by Bruning and co-workers on the possibility of the existence of charging phenomena below inception voltage, which may eventually cause deterioration of polymeric insulation. Moreover, with the aid of the Electromagnetic theory, some aspects of the Pedersen’s model are tried to be clarified, especially those which are correlated with space charges, electric dipoles, charge distribution, charge dynamics, and partial discharge activity.

scholarly journals Methods of assessing the quality of services: comparative analysis

2016 ◽  
Vol 4 (3) ◽  
pp. 374-382
Author(s):  
Н Ватолкина ◽  
N Vatolkina
Keyword(s):  
Comparative Analysis ◽  
Service Quality ◽  
Quality Assessment ◽  
Quality Evaluation ◽  
Quality Of Services ◽  
Methods Development ◽  
Methods Of Evaluation ◽  
Different Types ◽  
Service Quality Evaluation

The article presents a review of methods for assessing service quality on the basis of author´s classification in accordance with the evaluation subject and the purpose of the method. Author gives brief description of the main groups of methods of evaluation of components of service quality, evaluation of customer experience and evaluation of customer satisfaction; provides their comparative characteristics taking into account the evolutionary nature of the methods development. The author outlines specific features of quality assessment of service quality and makes the conclusion that general methods should be adapted to the services of different types and nature.

scholarly journals Comparative Analysis of the Importance of the Requirements of Passengers and Evaluating the Quality of Air and Bus Transport

2018 ◽  
Vol 236 ◽  
pp. 02006
Author(s):  
Vladimír Konečný ◽  
Róbert Berežný ◽  
Mária Kostolná ◽  
Pavel Šaradín
Keyword(s):  
Comparative Analysis ◽  
Quality Assessment ◽  
Quality Criteria ◽  
Point Of View ◽  
Individual Quality ◽  
Customer Requirements ◽  
Mode Of Transport ◽  
Bus Services ◽  
Bus Transport

The paper deals with the comparison of the importance of passengers’ requirements for the quality of the services provided and the quality assessment of air and bus transport. Individual quality criteria and their importance from the point of view of passengers vary depending on the mode of transport. It is also possible to observe the differing importance of quality criteria in relation to groups of passengers. The paper is processed comparison of the importance of individual quality criteria in air and bus services to the research in this area. In the paper is processed IPA matrix for air and bus transport. These are simple matrices that serve to highlight and understand important customer requirements.

scholarly journals Insulating Materials at Very Low Temperatures: A Short Review

2020 ◽  
Vol 10 (3) ◽  
pp. 5590-5595 ◽  
Author(s):  
P. Malelis ◽  
M. Danikas
Keyword(s):  
Electrode Surface ◽  
Low Temperatures ◽  
Short Review ◽  
Partial Discharges ◽  
Future Research ◽  
Insulating Materials ◽  
Factors Affecting

In this paper, a short review is given on insulating materials at very low temperatures. Various insulating materials are investigated in terms of phenomena such as partial discharges. Some of the factors affecting the behavior of the insulating materials at very low temperatures, such as the quality of electrode surface, the stressed insulation volume and the existing bubbles, are also reported and commented upon. Proposals for future research are also discussed.

scholarly journals Comparative Tests of Partial Discharges in Nomex® 910 Paper and Cellulose Paper

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 647
Author(s):  
Hubert Moranda ◽  
Hanna Moscicka-Grzesiak ◽  
Piotr Przybylek ◽  
Krzysztof Walczak ◽  
Radoslaw Szewczyk
Keyword(s):  
Moisture Content ◽  
Partial Discharge ◽  
Mineral Oil ◽  
Partial Discharges ◽  
Comparative Tests ◽  
Cellulose Paper ◽  
Pure Cellulose ◽  
Insulation Systems ◽  
Four Levels ◽  
Inception Voltage

The article presents the results of comparative investigations of partial discharges in two insulation systems; aramid-enhanced cellulose paper-mineral oil, and pure cellulose paper-mineral oil. Partial discharges were investigated in a diagonal electric field with vertical and horizontal components. This field is treated as the most dangerous for insulation. The research was carried out on Nomex® 910 paper and cellulose paper samples, each paper being 0.25 mm thick. Samples of the two materials were tested at four levels of moisture. The inception voltage of partial discharges of all samples tested decreased as their moisture content increases. It was also proved that Nomex® 910 has a significantly higher partial discharge inception voltage than the cellulose paper, although this difference decreased with increasing moisture content.

scholarly journals A method to reduce partial discharges in motor windings fed by PWM inverter

Open Physics ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 599-604 ◽  
Author(s):  
Daniel Roger ◽  
Sonia Ait-Amar ◽  
Ewa Napieralska
Keyword(s):  
Partial Discharge ◽  
Partial Discharges ◽  
Conducting Layer ◽  
Element Analysis ◽  
New Approach ◽  
Pwm Inverter ◽  
Additional Layer ◽  
Ac Motor ◽  
Critical Zones ◽  
Inception Voltage

AbstractA new approach for designing ac motor windings free of partial discharges (PD) is proposed. The method consists of adding a thin conducting layer on the outer surface of the enameled wire used for building the machine winding. With this additional layer, PDs occur only in critical zones localized near the wire connections rather than randomly in the residual voids between turns. With such deterministic localizations, it is possible to reduce strongly the PD activity by adding small quantities of varnish in the determined critical zones. After studying the validity of the Paschen’s hypotheses for this application, the Paschen’s law is coupled to an electrostatic finite element analysis, for predicting the Partial Discharge Inception Voltage (PDIV), which corresponds to the electronic avalanche ignition in the air of critical zones.

scholarly journals Oil Aging due to Partial Discharge Activity

2018 ◽  
Author(s):  
M Ghaffarian Niasar ◽  
H Edin ◽  
R Clemence Kizza
Keyword(s):  
Breakdown Strength ◽  
Partial Discharge ◽  
High Energy ◽  
Partial Discharges ◽  
Electric Discharges ◽  
Complete Arc ◽  
Long Time ◽  
Lightning Impulse ◽  
Paper Ageing ◽  
Short Time

<p>Oil is the main insulation in power transformers and over long time of ageing its insulation properties can change. In this paper ageing of oil due to the exposure to electric discharges was investigated. The effect of high energy discharges (complete arc) and low energy discharges (partial discharges) on oil properties such as breakdown strength and oil conductivity was investigated.<br />An experimental setup consisting of two spherical electrodes was designed. The adjustable distance between the two electrodes made it possible to have PD with different magnitude.<br />The oil conductivity and breakdown strength was measured for three sets of experiments. The first group of experiments was performed on new oil in order to have a reference for comparison. In the second group of experiments the new oil samples was exposed to 1000 and 3000 lightning impulses. In the third group of experiments new oil samples was exposed to partial discharge for different duration of time. Oil conductivity and breakdown strength of these aged samples were compared with new oil. The results show that after exposure to lightning impulse oil conductivity increases and breakdown strength decreases, However PD activity for short time does not change the oil conductivity but it reduces the breakdown strength.</p>

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