Submit to Energies Review for Energies Propose a Special Issue

Journal Browser

► Journal Browser

High Voltage Insulating Materials-Current State and Prospects 2022

Print Special Issue Flyer
Special Issue Editors
Special Issue Information
Keywords
Published Papers

A special issue of Energies (ISSN 1996-1073). This special issue belongs to the section "F6: High Voltage".

Deadline for manuscript submissions: closed (31 March 2023) | Viewed by 12133

Share This Special Issue

Special Issue Editors

Prof. Dr. Pawel Rozga

E-Mail Website
Guest Editor

Institute of Electrical Power Engineering, Lodz University of Technology, Stefanowskiego 20, 90-537 Lodz, Poland
Interests: high-voltage engineering; pre-breakdown and breakdown phenomena in dielectric liquids; alternative dielectric liquids for electrical purposes; statistics in electrical engineering; partial discharges; insulation of power transformers
Special Issues, Collections and Topics in MDPI journals

Prof. Dr. Abderrahmane Beroual

E-Mail Website
Guest Editor

Département Electronique, Energie Electrique, Automatique, École Centrale de Lyon, 69134 Ecully, France
Interests: high voltage engineering; insulation coordination; outdoor insulation; dielectric materials (gases, liquids, nanofluids, interfaces); long air gaps discharge and lightning; modelling of discharges and composite materials
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The proper operation of high-voltage devices, especially transformers, is mainly determined by their insulation conditions. Solid, liquid, and gaseous dielectrics used as electrical insulation in high-voltage equipment must ensure correct, continuous, uninterrupted, and safe operation of the devices. In addition, ensuring an appropriate level of environmental safety is extremely important. Insulation materials work under conditions of high temperature, high electric fields, or mechanical stresses. Such conditions require high-quality materials, which should not change over time. Therefore, it is very important to study the properties of materials used in high-voltage equipment from various perspectives, such as electrical (AC, DC, LI, or combined exposure), thermal (e.g., accelerated aging), or chemical (impact of environmental factors or material compatibility). In all these areas, researchers are seeking to find optimal solutions for insualting materials that will work well in industrial applications. The development of the HVDC technology, which involves specific stress conditions and thus specific physical phenomena associated with stress, has become extremely important in this respect.

Since insulating materials are constantly developing and new materials keep appearing in the market (e.g., biodegradable insulating liquids in the case of liquid dielectrics or nano-fluids), this Special Issue will be focused on all aspects of new solutions proposed for use in high-voltage applications.

Therefore, papers that deal with the study of the dielectric and thermal properties of insulation materials for electrical applications and those focused on other properties of dielectrics are warmly welcomed. Studies on the chemical structure of materials and on the impact of this structure (admixtures, nanoparticles) on the properties of single dielectrics and mixtures are also of interest. Papers may as well report research methods to study insulating materials in the laboratory testing phase as well as in operating conditions.

Prof. Dr. Pawel Rozga
Prof. Dr. Abderrahmane Beroual
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Energies is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

new solutions within solid, liquid, and gaseous dielectrics
testing of dielectric materials under AC, DC, and LI voltages
HV equipment isolation systems (power transformers, transmission lines, substations, switchgears etc.)
pre-breakdown and breakdown phenomena in dielectrics
aging tests
measurement techniques
characterization methods and techniques

Published Papers (7 papers)

Download All Papers

Research

Jump to: Review, Other

11 pages, 2334 KiB

Open AccessArticle

Influence of Dielectric Liquid Type on Partial-Discharge Inception Voltage in Oil-Wedge-Type Insulating System under AC Stress

by Bartlomiej Pasternak and Pawel Rozga

Energies 2023, 16(2), 1005; https://doi.org/10.3390/en16021005 - 16 Jan 2023

Cited by 4 | Viewed by 1734 | Correction

Abstract

This article describes the results of laboratory tests on an oil-wedge-type electrode system, which were supplemented by FEM (finite element method) simulations. The studies were focused on the comparison of the partial-discharge inception voltage (PDIV) in the abovementioned system when immersed in different liquid dielectrics, namely inhibited mineral oil, uninhibited mineral oil, synthetic ester, and natural ester. In addition, the electric field stress obtained from the simulations was used in each case to determine the safe level for the actual transformer insulation. The studies were performed under AC voltage. Both electrical and optical detection methods were applied in order to properly determine the discharge inception. The statistical analysis of the results obtained from the laboratory measurements was carried out using Weibull distribution. We found that both mineral oils demonstrated better properties than the ester liquids in terms of resistance against partial-discharge appearance under the conditions of the oil-wedge-type electrode model. Therefore, for all considered cases, the inception electric field stress obtained from the FEM-based simulations corresponding to the partial-discharge inception voltage was found to be significantly higher than the commonly accepted safe design level, which is in the range of 10–12 kV/mm. This proved the good electrical strength of all liquids under test. Full article

(This article belongs to the Special Issue High Voltage Insulating Materials-Current State and Prospects 2022)

► Show Figures

Figure 1

9 pages, 1994 KiB

Open AccessArticle

Classification of Partial Discharges Recorded by the Method Using the Phenomenon of Scintillation

by Aleksandra Płużek and Łukasz Nagi

Energies 2023, 16(1), 201; https://doi.org/10.3390/en16010201 - 25 Dec 2022

Viewed by 1012

Abstract

Classification is one of the most common methods of supervised learning, which is divided into a process of data acquisition, data mining, feature analysis, machine learning algorithm selection, model learning and validation, as well as prediction of the result, which was done in the current work. The data that were analyzed concerned ionizing radiation signals generated by partial discharges, recorded by a method using the phenomenon of scintillation. It was decided to check if the data could be classified and if it was possible to determine the defect of an electrical power device. It was possible to find out which classifier (algorithm) worked best for the task, and that the data obtained can be classified, as well as that it is possible to determine the defect. In addition, it was possible to check what effect changing the default values of the classifier’s parameters has on the effectiveness of classification. Full article

(This article belongs to the Special Issue High Voltage Insulating Materials-Current State and Prospects 2022)

► Show Figures

Figure 1

11 pages, 2489 KiB

Open AccessArticle

Detection of Cellulose Particles in Transformer Oil Based on Transport of Intensity Equation

by Hao Pan, Liang Xue, Chuankai Yang, Fenghong Chu, Youhua Jiang, Hongmei Zhu, Yue Li and Lei Xin

Energies 2022, 15(16), 5836; https://doi.org/10.3390/en15165836 - 11 Aug 2022

Cited by 2 | Viewed by 1225

Abstract

Cellulose particles are among the aging products of the insulating paper that are used in power transformers. Too many cellulose particles can cause transformer accidents. Traditional research and detection methods that are used for this problem generally focus on the number and length information of cellulose particles, and it is usually difficult to quantitatively describe the spatial shape of cellulose particles. However, the shape of cellulose particles is also one of the factors affecting the safety of transformer insulation. In this paper, we successfully extracted quantitative information of the spatial shape of cellulose particles in transformer oil using an image processing technique and the transport of intensity equation, providing a new novel approach for the study and detection of the shape of cellulose particles in transformer oil. Full article

(This article belongs to the Special Issue High Voltage Insulating Materials-Current State and Prospects 2022)

► Show Figures

Figure 1

13 pages, 3533 KiB

Open AccessArticle

Raman Spectroscopy Characterization of Mineral Oil and Palm Oil with Added Multi-Walled Carbon Nanotube for Application in Oil-Filled Transformers

by Nur Sabrina Suhaimi, Mohd Taufiq Ishak, Muhamad Faiz Md Din, Fakhroul Ridzuan Hashim and Abdul Rashid Abdul Rahman

Energies 2022, 15(4), 1534; https://doi.org/10.3390/en15041534 - 19 Feb 2022

Cited by 4 | Viewed by 2843

Abstract

This century is experiencing a generation of nanotechnologies that makes use of the remarkable properties of nanofluids in applications such as electrical systems, industrialization, and others. In this paper, mineral oil (MO) and palm oil (PO), with multi-walled carbon nanotube (CNT), have been synthesized for use in oil-filled transformer applications. This research aims to use Raman characterization to assess the feasibility of CNT nanofluids samples at 0.02 g/L and 0.03 g/L concentrations. The chemical structure bonding that exists in the Raman band between 700 cm⁻¹ and 3100 cm⁻¹ regions is identified and analyzed, accordingly. After baseline removal and normalization, the precision band location and intensity of oil samples are fitted with a Gaussian profile. It was discovered that the peak at ~1440 cm⁻¹ has the highest intensity for six oil samples, which is attributed to the (C–H) methylene scissors vibration of the CH₂ group. Based on the FWHM profile and integrated area under the curve of PO, it was discovered that CNT contributes to the structural stability defect of PO. Principal component analysis (PCA) is also used in this study to classify different samples based on chemical composition and identify the spectral characteristics with the highest degree of variability. Full article

(This article belongs to the Special Issue High Voltage Insulating Materials-Current State and Prospects 2022)

► Show Figures

Figure 1

11 pages, 4024 KiB

Open AccessArticle

Influence of Temperature on Lightning Performance of Mineral Oil

by Pawel Rozga, Filip Stuchala, Tomasz Piotrowski and Abderrahmane Beroual

Energies 2022, 15(3), 1063; https://doi.org/10.3390/en15031063 - 31 Jan 2022

Cited by 6 | Viewed by 1883

Abstract

This article deals with the influence of temperature on the lightning impulse breakdown voltage (LI BDV) of mineral oil in a non-uniform electric field. The experiments were performed in point–plane electrode arrangements under a standard lightning impulse voltage of negative polarity. The LI BDV for the temperatures of 20, 40, 60, 80, 100 and 110 °C was measured using a step method with registration of the light signals emitted during pre-breakdown and breakdown phases. The average propagation velocity was also determined. The results confirm that the mineral oil tested under LI voltage behaves similarly to AC voltage-based stress. The LI BDV increases with temperature up to 100 °C and then tends to decrease. The results demonstrated that viscosity dependent processes are responsible for increasing the LI BDV with temperature up to the 100 °C; and liquid vapor formation processes are responsible for decreasing the LI BDV at temperatures equal to and higher than 100 °C. Full article

(This article belongs to the Special Issue High Voltage Insulating Materials-Current State and Prospects 2022)

► Show Figures

Figure 1

Review

Jump to: Research, Other

24 pages, 2038 KiB

Open AccessReview

A Critical Overview of the Impact of Nanoparticles in Ester Fluid for Power Transformers

by Arputhasamy Joseph Amalanathan, Ramanujam Sarathi and Maciej Zdanowski

Energies 2023, 16(9), 3662; https://doi.org/10.3390/en16093662 - 24 Apr 2023

Viewed by 1477

Abstract

This paper examines the impact of various nanoparticles on ester fluids with a special focus on their usage towards power transformers. The precautionary measures to be considered on the nanofluids such as preparation methodologies with an appropriate surfactant and its stability is well elucidated. The electrical double layer (EDL) formation around the nanoparticles on its diffusion in the insulating fluid is explained by its different layers away from the particle surface. The partial discharge of ester nanofluids with different detection methods is elaborated on its comparison with conventional IEC 60270 measurements. The field configurations on ester-nanofluids govern the breakdown mechanism with variations in the streamer patterns. The equation of relaxation time towards breakdown is valid only when it is lower than the initiation time for streamers. The flow charges induced at the solid/liquid interface inside transformers depends on the structure of the nanofluid and the condition of pressboard/paper insulation. The impact of different concentrations of nanoparticles on ester nanofluids observes a change in its flow behaviour affecting the streaming current. The permittivity of nanofluid depends on the polarization of nanoparticles where the Clausius-Mossotti equation governing this mechanism is explained towards ester-nanofluids. The viscosity of nanofluids observed no significant variation whereas the other physio-chemical properties such as flash point, interfacial tension, and oxidation stability improved depending on the type of nanoparticle. The addition of metal-oxide nanoparticles on ester fluids increases thermal conductivity with different models proposed based on the structure and shape of a nanoparticle. The impact of ageing on nanofluids observes an instability over a longer ageing duration with specific nanoparticles which should be better understood before implementing them in real-time power transformers. Full article

(This article belongs to the Special Issue High Voltage Insulating Materials-Current State and Prospects 2022)

► Show Figures