Advances in Electrical Equipment Insulation for New Power Systems

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Electrical, Electronics and Communications Engineering".

Deadline for manuscript submissions: closed (31 December 2023) | Viewed by 2834

Special Issue Editors

School of Electrical and Electronic Engineering, North China Electric Power University, Beijing 102206, China
Interests: electrical insulation design; condition monitoring for power equipment; fault diagnosis for power equipment
College of Electrical & Information, Engineering, Hunan University, Changsha, China
Interests: electromagnetic transients in power system; high voltage engineering; renewable energy
Special Issues, Collections and Topics in MDPI journals
School of Physics & Electronic Science, Changsha University of Science & Technology, Changsha 410012, China
Interests: electrical insulation design; condition monitoring for power equipment; fault diagnosis for power equipment

Special Issue Information

Dear Colleagues,

China has set a goal to achieve peak CO2 emissions before 2030 and carbon neutrality by 2060. To achieve the goal, the State Grid has issued a great plan on the construction of new power system, which will be low-carbon, more flexible and efficient, more intelligent and environmentally friendly, etc. The development of a new power system poses challenges and higher requirements for electrical insulation, such as the necessity of new environmentally friendly insulation dielectrics, more accurate sensors, repair for insulating materials, etc. This Special Issue of Applied Sciences provides an opportunity for researchers to share their latest discoveries and best practices in this field. The aim is to present a selected contribution on advances in electrical equipment insulation for new power systems.

Potential topics include but are not limited to:

  • Environmentally friendly insulating dielectrics for new power systems;
  • Insulation of electrical equipment under extreme conditions;
  • Electrical insulation for power electronic equipment;
  • Modern sensors for insulation condition monitoring in power systems;
  • Advances in numerical simulation for electrical insulation design;
  • Intelligent fault diagnosis and repair of electrical equipment insulation;
  • Other insulation-related technology.

Dr. Haoxi Cong
Dr. Qiuqin Sun
Dr. Feng Bin
Guest Editors

Manuscript Submission Information

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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. Applied Sciences 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 2400 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

  • modern power system
  • electrical insulation
  • fault diagnosis for power equipment
  • numerical simulation for insulation design
  • artificial intelligence

Published Papers (3 papers)

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Research

21 pages, 10400 KiB  
Article
Study on Power Frequency Breakdown Characteristics of Nano-TiO2 Modified Transformer Oil under Severe Cold Conditions
Appl. Sci. 2023, 13(17), 9656; https://doi.org/10.3390/app13179656 - 26 Aug 2023
Viewed by 764
Abstract
With 45# transformer oil as the base fluid, different concentrations of TiO2 nanomodified transformer oil were prepared via the thermal oscillation method. Nanomodified transformer oil with a concentration of 0.01 g/L was selected for evaluation via the breakdown test. Then, 0.01 g/L [...] Read more.
With 45# transformer oil as the base fluid, different concentrations of TiO2 nanomodified transformer oil were prepared via the thermal oscillation method. Nanomodified transformer oil with a concentration of 0.01 g/L was selected for evaluation via the breakdown test. Then, 0.01 g/L nanomodified transformer oil and ordinary 45# transformer oil were subjected to the variable control of different moisture contents and different temperatures, and breakdown tests under different types of electrodes were performed within the temperature range of −30 °C to 30 °C. The test results showed the following: Under severe cold conditions, the improvement effect of the breakdown voltage in different temperature ranges was different. Within the temperature range of −30 °C to −10 °C, the enhancement effect could reach 13% to 15%. Within the temperature range of −10 °C to 0 °C, the enhancement effect could reach 8% to 9%. Within the temperature range of 0 °C to 30 °C, the enhancement effect could reach 18% to 21%. Compared with the test results at high water contents, the improvement in the breakdown voltage amplitude of transformer oil by nanomaterials was more obvious at low water contents. In addition, nanomaterials could reduce the dispersion of the breakdown voltage to make the breakdown voltage more stable. Lastly, COMSOL was used to simulate the polarization process of nanoparticles under a uniform electric field and the influence of the trajectory of charged particles in the oil to further analyze the mechanism of the influence of nanoparticles in oil on the breakdown voltage of the oil gap. The simulation results showed that, when the particles were accelerated by the electric field, they moved irregularly. After adding nanoparticles, the charged particles were adsorbed by the nanoparticles when passing through the nanoparticles, which reduced the migration rate of charged particles in the oil. The breakdown voltage of the oil gap increased. Full article
(This article belongs to the Special Issue Advances in Electrical Equipment Insulation for New Power Systems)
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17 pages, 5902 KiB  
Article
Analysis of the Insulation Characteristics of Hexafluorobutene (C4H2F6) Gas and Mixture with CO2/N2 as an Alternative to SF6 for Medium-Voltage Applications
Appl. Sci. 2023, 13(15), 8940; https://doi.org/10.3390/app13158940 - 03 Aug 2023
Viewed by 845
Abstract
This paper investigates C4H2F6, a promising environmentally friendly insulating gas that possesses high dielectric strength and a low global warming potential. The study focuses on examining the insulation properties of C4H2F6 when [...] Read more.
This paper investigates C4H2F6, a promising environmentally friendly insulating gas that possesses high dielectric strength and a low global warming potential. The study focuses on examining the insulation properties of C4H2F6 when combined with CO2/N2, aiming to assess its suitability as a substitute for SF6 in gas-insulated applications. Finite element analyses are performed to evaluate the field utilization factor and electric field distribution in the proposed mixture. The properties of liquefaction temperature were examined in this study to determine the optimal mixing ratio for applications that require a minimum working temperature. Extensive experimental investigations were carried out to assess the dielectric strength characteristics of the gas mixture in both uniform and quasi-uniform electric fields. It was found that pure HFO-1336mzz (E) exhibits a dielectric strength approximately 1.2–1.6 times higher than SF6. Experimental results have revealed that the insulation performance of a 30% HFO-1336mzz (E)/CO2 mixture closely resembles that of SF6, with a matching efficiency of up to 90% in a weakly uniform electric field. This remarkable performance can be attributed to a positive synergistic effect between HFO-1336mzz (E) and CO2, combined with the gas mixture’s excellent self-recoverability property. These experimental findings are further supported by finite element analysis, which confirms the observed results. The 30% HFO-1336mzz (E)/CO2 gas mixture at 0.15–0.20 MPa pressure and constant 0.6 mm air gap reveal superior insulation tolerance and less sensitivity to the electric field, confirming its promising medium-voltage engineering applications. The associated results of this research provide a critical reference for the engineering application of the alternating (AC) and direct current (DC) insulation characteristics of the HFO-1336mzz (E)/CO2 gas mixture. Full article
(This article belongs to the Special Issue Advances in Electrical Equipment Insulation for New Power Systems)
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16 pages, 7163 KiB  
Article
Study on the Partial Surface Discharge Process of Oil-Paper Insulated Transformer Bushing with Defective Condenser Layer
Appl. Sci. 2023, 13(13), 7621; https://doi.org/10.3390/app13137621 - 28 Jun 2023
Viewed by 812
Abstract
Oil-impregnated paper condenser transformer bushings are an important part of transformer equipment, and partial discharge (PD) occurred when defects exist on the condenser aluminum foil layers. Firstly, to study the PD process of the oil-paper insulated capacitance graded bushing with the defect of [...] Read more.
Oil-impregnated paper condenser transformer bushings are an important part of transformer equipment, and partial discharge (PD) occurred when defects exist on the condenser aluminum foil layers. Firstly, to study the PD process of the oil-paper insulated capacitance graded bushing with the defect of broken aluminum foil, a defective oil-paper bushing discharge sample is constructed to study the PD parameters and capacitance, and to discharge carbonization traces at different voltage levels. Then, in order to verify the process of condenser aluminum foil layer discharge and the space charge variation in the oil-paper insulation system of a sample model, the surface flashovers of a needle-plane discharge model based on the bipolar charge transport model and the hydrodynamic model was built. The simulation, by Transport of Diluted Species physics of COMSOL Multiphysics software, points out the discharge process of aluminum foil electrode caused by space charge action and electric field distortion under an electric field at different voltages. The results of simulation and sample bushing experiments showed that the PD process of the defective condenser foil layer is mainly divided into three stages: tip corona discharge, streamer in oil, and surface flashovers. The voltage amplitude is larger the more electrical branches are discharged and the shorter the discharge time is. The findings of the article have important implications for the discharge of the foil layer inside the oil-paper bushing. Full article
(This article belongs to the Special Issue Advances in Electrical Equipment Insulation for New Power Systems)
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