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 Effect of Test Method and Needle Plane Configuration on Partial Discharge Inception Voltage Measurement of Mineral Oil based on Weibull Analysis

2013 ◽  
Vol 11 ◽  
pp. 411-418 ◽  
Author(s):  
T.F. Sipahutar ◽  
A.A. Kemma ◽  
N. Pattanadech ◽  
F. Pratomosiwi ◽  
Suwarno ◽  
...  
Keyword(s):  
Partial Discharge ◽  
Mineral Oil ◽  
Test Method ◽  
Weibull Analysis ◽  
Voltage Measurement ◽  
Inception Voltage

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 Pre-Breakdown and Breakdown Behavior of Synthetic and Natural Ester Liquids under AC Stress

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 167
Author(s):  
Beki Sékongo ◽  
Stephan Brettschneider ◽  
U. Mohan Rao ◽  
Issouf Fofana ◽  
Marouane Jabbari ◽  
...  
Keyword(s):  
Electric Field ◽  
Thermal Aging ◽  
Power Transformer ◽  
Partial Discharge ◽  
Service Condition ◽  
Mineral Oil ◽  
Radius Of Curvature ◽  
Long Term Behavior ◽  
Inception Voltage

In the last decades, a large focus is being placed on the sustainability and safety of the power transformer spectrum. Ester liquids, which have interesting properties such as high fire point and biodegradability, are gaining needed attraction. Since in-service condition, thermal aging deteriorates the physicochemical and electrical properties of liquid dielectrics, it is important to study their long-term behavior. In this contribution, the pre-breakdown and breakdown behavior of ester fluids (synthetic and natural) under AC stress are investigated. Important characteristics, such as partial discharge pre-inception voltage, partial discharge inception voltage, breakdown voltage, average streamer velocity, and inception electric field, were assessed. The influence of the radius of curvature (of high voltage needle electrode) as well as the thermal degradation of typical ester liquids are also discussed. Mineral oil was also included in the tests loop as a benchmark for comparative purposes. It is found that the pre-inception voltage of ester liquids was, in most cases, higher than that of mineral oil. For a given radius of curvature, the streamer inception and breakdown voltages decreased with thermal aging. During the streamer initiation, the electric field at the electrode tip decreased with the increase in the radius of curvature. The velocity of the streamers seems to increase with the decrease in the radius of curvature. The period of vulnerability, the so-called “delay time”, seems to be independent of the aging or the radius of curvature for a given condition of the liquid.

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 Using the Method of Harmonic Distortion Analysis in Partial Discharge Assessment in Mineral Oil in a Non-Uniform Electric Field

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4830
Author(s):  
Alper Aydogan ◽  
Fatih Atalar ◽  
Aysel Ersoy Yilmaz ◽  
Pawel Rozga
Keyword(s):  
Electric Field ◽  
Leakage Current ◽  
High Voltage ◽  
Partial Discharge ◽  
Harmonic Distortion ◽  
Mineral Oil ◽  
Significant Rise ◽  
Partial Discharges ◽  
Uniform Electric Field ◽  
Different Diameters

In high-voltage equipment, it is vital to detect any failure in advance. To do this, a determination of the partial discharges occurring at different voltage types as well as at different electrode configurations is essential for observing the oil condition. In this study, an experimental setup consisting of a needle–semi-sphere electrode configuration immersed in mineral oil is prepared for laboratory experiment. In such a way, a non-uniform electric field is created and the leakage currents are monitored from the grounded electrode. A total of six different electrode configurations are analyzed during the tests by the use of hemispheres of different diameters as grounded electrodes and copper and steel pointed (medical) needle high-voltage electrodes. In the experiments, the partial discharges occurring at four different voltage levels between 5.4 and 10.8 kV are measured and recorded. The effect of the different electrode configurations and voltage levels on the harmonic distortion are noted and discussed. It is experimentally confirmed that it is possible to measure the leakage current caused by the partial discharges of the corona type in oil at the different metal points, creating high-voltage electrodes and different electric field distributions based on the proposed non-invasive measurement technique. The studies showed that there is a significant rise of even harmonic components in the leakage current during the increase in the partial discharge intensity with the 5th harmonic as dominant.

scholarly journals Uncertainty Sources in the Estimation of the Partial Discharge Inception Voltage in Turn-to-Turn Insulation Systems

IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 157510-157519
Author(s):  
Manuel Gomez La De Calle ◽  
Juan Manuel Martinez-Tarifa ◽  
Angel Manuel Gomez Solanilla ◽  
Guillermo Robles
Keyword(s):  
Partial Discharge ◽  
Uncertainty Sources ◽  
Insulation Systems ◽  
Turn Insulation ◽  
Inception Voltage
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