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 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.

Inhibiting Effect of Nonlinear Shielding Layer on Electrical Tree Propagation inside Insulation Layer of High-Voltage Cable

2014 ◽  
Vol 989-994 ◽  
pp. 1273-1277
Author(s):  
Chang Ming Li ◽  
Bao Zhong Han ◽  
Long Zhao ◽  
Chun Peng Yin
Keyword(s):  
Electric Field ◽  
Field Distribution ◽  
High Voltage ◽  
Electric Field Distribution ◽  
Uniform Electric Field ◽  
Insulation Layer ◽  
Breakdown Time ◽  
Electrical Tree ◽  
Traditional Structure ◽  
Initiation And Propagation

Nonlinear insulated materials can uniform electric field distribution in non-uniform electric field. In order to inhibit the electric tree initiation and propagation inside high-voltage cross-linked polyethylene (XLPE) insulated cable, a kind of 220kV high-voltage XLPE insulated cable with new structure is designed by embedding nonlinear shielding layer into XLPE insulation layer of high-voltage cable with traditional structure in this study. Experimental and simulation results indicate that the nonlinear shielding layer can effectively inhibit electrical tree propagation inside the XLPE specimens, and obviously extend the breakdown time caused by electric tree propagation. When the electrical tree propagates into the nonlinear shielding layer sandwiched between insulation layers of cable, the electric field distribution near the tip of electrical tree is obviously improved. These findings prove the feasibility and the effectivity of inhibiting electrical tree propagation inside high-voltage cable by adding nonlinear shielding layer into the insulation layer.

scholarly journals Simulations of High Non-Uniform Electric Field in Dielectric Barrier Electrode System

2021 ◽  
Vol 18 (14) ◽  
Author(s):  
Pitchasak CHANKUSON ◽  
Mudtorlep NISOA
Keyword(s):  
Electric Field ◽  
High Voltage ◽  
High Intensity ◽  
Dielectric Materials ◽  
Electrode System ◽  
Ozone Production ◽  
Uniform Electric Field ◽  
Electrode Geometry ◽  
Dielectric Barrier ◽  
Fine Mesh

An electric field in the dielectric barrier electrode system is necessary for ozone production because ozone is produced by the electric discharge of O2 under a high-intensity electric field. The gas discharge plasmas contain energetic particles, such as electrons, ions, atoms, and radicals. The recombination of the O atom and O2 in the plasma will form O3. In this paper, the dependence of DC electric field formation on electrode geometry and the gap between electrodes and dielectric materials were examined by using computational modeling. Thus, a set of electrode geometry, gap distance, and dielectric material were obtained for high-intensity and uniform electric field generation. The COMSOL Multiphysics software was used for the modeling. Among the electrode geometries of plate-plate, pin-plate and mesh-plate, the mesh-plate generated high-intensity and uniform electric field. In the modeling, dielectric materials, including quartz, mica, alumina, and water, were compared. The highest intensity of electric field occurred on the water surface. HIGHLIGHTS When the gap distance between two parallel electrodes is less than 100 mm, the electric field in the gap is constant, independent of the space A high-intensity and uniform electric field is generated in the gap between the dielectric and grounded electrodes when a fine mesh high-voltage electrode is utilized With the fine mesh electrode, the electric field is about two times higher than the conventional plate electrodes, whereas the electric field uniformity was about 90 %. Therefore the barrier discharge will be initiated with lower high voltage GRAPHICAL ABSTRACT

scholarly journals Experimental determination of partial discharges in a model of a digital instrument transformer by differential method

Vestnik IGEU ◽  
2019 ◽  
pp. 32-42
Author(s):  
A.V. Gusenkov ◽  
V.D. Lebedev ◽  
S.N. Litvinov ◽  
S.A. Slovesny ◽  
A.A. Yablokov
Keyword(s):  
Condition Monitoring ◽  
High Voltage ◽  
Partial Discharge ◽  
Essential Elements ◽  
Differential Method ◽  
Partial Discharges ◽  
Discharge Characteristics ◽  
Reliability Indicators ◽  
Instrument Transformer ◽  
Inductive Sensors

Power facilities are now implementing the concept of smart grid and its essential elements – high-voltage digital current and voltage transformers. However, the implementation of digital technologies is slowed down by the lack of operation experience and reliability indicators. One of the main causes of high-voltage equipment failures is insulation damage. The most informative parameters determined by insulation evaluation are partial discharge characteristics. There are rated values of these characteristics for rotating electrical machines and power transformers measured by external equipment. But the existing method of partial discharge analysis cannot be applied to digital current and voltage transformers as there are no criteria for tripping of the innovative equipment with comprehensive insulation. All this urges us to study the possibility to determine experimentally the characteristics of partial discharges in the insulation of digital current and voltage transformers by using embedded inductive sensors in order to develop a method for condition monitoring of digital current and voltage transformers and improving of their reliability. In this work, we have used a model of digital current and voltage transformers, a high-voltage test unit, a digital multi-input oscciloscope and inductive sensors. The experiment includes: detecting partial discharges in the model of digital current and voltage transformers by the external bridge connection, recording the voltage at which partial discharges occur in the simulated fault area, measuring the corresponding value of the apparent charge of the partial discharge, detecting partial discharges in the model of digital current and voltage transformers by a differential method with the help of embedded inductive sensors. The characteristics of partial discharges in the simulated fault area have been experimentally determined on a model of digital current and voltage transformers. The pulse voltage on the embedded inductive sensor corresponding to the apparent charge of 80 pC was equal to 600 mV at the test voltage of 2,7 kV. Embedded inductive sensors allow implementing the method of insulation condition monitoring for digital current and voltage transformers in accordance with the partial discharge characteristics both at the stages of production and operation extending the potential of the electronic (microprocessor) module and increasing the reliability of digital current and voltage transformers.

Partial discharge characteristics of bubble flow under AC non-uniform electric field in FC-72

2020 ◽  
Vol 27 (4) ◽  
pp. 1119-1127
Author(s):  
Shenyang Mo ◽  
Zhibin Zhao ◽  
Xuebao Li ◽  
Xiang Cui ◽  
Jiayu Xu ◽  
...  
Keyword(s):  
Electric Field ◽  
Partial Discharge ◽  
Uniform Electric Field ◽  
Bubble Flow ◽  
Discharge Characteristics
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