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 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 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.

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 Modelling of Partial Discharges in Polymeric Insulation Exposed to Combined DC and AC Voltage

2018 ◽  
Author(s):  
Pål Keim Olsen ◽  
Frank Mauseth ◽  
Erling Ildstad
Keyword(s):  
Electric Field ◽  
Field Distribution ◽  
Electric Field Distribution ◽  
Partial Discharge ◽  
Partial Discharges ◽  
Lumped Parameter Model ◽  
Dc Voltage ◽  
Discharge Activity ◽  
Lumped Parameter ◽  
Cylindrical Cavities

<p>This paper addresses the influence of an AC voltage superimposed on DC voltage on the partial discharge activity in artificial cylindrical cavities in polymer insulation. The main purpose was to investigate the feasibility of calculating the electric field distribution in such a configuration using a simple lumped parameter model. Two models for calculating the electric field have been compared, the lumped parameter classic</p>

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.

Partial Discharge Activity of Inter-turn Insulation under Different Parameters of Square Wave Voltage

2009 ◽  
Vol 129 (12) ◽  
pp. 922-930 ◽  
Author(s):  
Kai Zhou ◽  
Guangning Wu ◽  
Xiaoxia Guo ◽  
Liren Zhou ◽  
Tao Zhang
Keyword(s):  
Partial Discharge ◽  
Square Wave ◽  
Discharge Activity ◽  
Turn Insulation

Influence of Space Charge Accumulation by Pre-stress on Partial Discharge Inception Voltage

2020 ◽  
Vol 140 (5) ◽  
pp. 276-284
Author(s):  
Maimi Mima ◽  
Tokihiro Narita ◽  
Hiroaki Miyake ◽  
Yasuhiro Tanaka ◽  
Masahiro Kozako ◽  
...  
Keyword(s):  
Space Charge ◽  
Partial Discharge ◽  
Charge Accumulation ◽  
Inception Voltage

scholarly journals Device for online monitoring of insulation faults in high-voltage switchgears

2021 ◽  
Vol 17 (2) ◽  
pp. 155014772199928
Author(s):  
Jiajia Song ◽  
Jinbo Zhang ◽  
Xinnan Fan
Keyword(s):  
Fourier Transform ◽  
High Voltage ◽  
Online Monitoring ◽  
Pulse Current ◽  
Partial Discharge ◽  
Current Method ◽  
Capacitive Sensor ◽  
Accurate Diagnosis ◽  
Partial Discharges ◽  
Urgent Problem

Partial discharges are the major cause of deterioration in the insulation characteristics of switchgears. Therefore, timely detection of partial discharge in switchgear and potential insulation faults is an urgent problem that needs to be addressed in the power supervision industry. In this study, a device was proposed for online monitoring of high-voltage switchgears based on pulse current method and ozone (O3) detection. The pulse current method obtains the PD signal by monitoring the phase holes on the switch indicator. Occurrence of a partial discharge in a certain phase leads to the production of a discharge pulse, which can be coupled out by a capacitive sensor. The current spectrum and the O3 produced by partial discharge were processed via fast Fourier transform for accurate diagnosis of the occurrence of partial discharge and its severity in switchgears. The proposed method allows for convenient acquisition of the partial discharge signal, simple installation of the device, and realization with inexpensive sensors.

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