Submit to Special Issue Submit Abstract to Special Issue Review for Energies Propose a Special Issue

Journal Menu

Journal Browser

Research on Power Transformers, Power Cable, High Voltage and Insulation Technology

Print Special Issue Flyer
Special Issue Editors
Special Issue Information
Keywords
Benefits of Publishing in a Special Issue
Published Papers

A special issue of Energies (ISSN 1996-1073). This special issue belongs to the section "F1: Electrical Power System".

Deadline for manuscript submissions: 25 June 2026 | Viewed by 1860

Share This Special Issue

Special Issue Editor

Prof. Dr. Xuetong Zhao

E-Mail Website
Guest Editor

State Key Laboratory of Power Transmission Equipment Technology, School of Electrical Engineering, Chongqing University, Chongqing 400044, China
Interests: power transformer; power cable; high-voltage; insulating materials; dielectric physics; energy storage materials

Special Issue Information

Dear Colleagues,

This Special Issue aims to present and disseminate the latest research developments in the field of diagnostics, condition monitoring, and aging assessment of electrical power equipment, with a particular focus on insulation systems and fault detection mechanisms. Ensuring the reliable operation of key assets such as transformers, HVDC cables, converters, circuit breakers, and other components in modern power grids requires advanced tools for real-time monitoring and early fault identification.

We welcome contributions addressing novel methods in condition assessment, electrical insulation diagnostics, and degradation modelling, as well as studies applying artificial intelligence and image and signal processing techniques to detect, localize, and classify faults. Research that explores new trends in DC diagnostics, especially for emerging HVDC systems, and simulation-based approaches to study insulation behavior under complex operating stresses, is also encouraged.

Topics of interest include, but are not limited to, the following:

Condition monitoring and diagnostics of electrical power equipment;
Aging and degradation assessment of electrical power equipment;
Diagnostics and monitoring of electrical insulation;
Emerging diagnostics methods;
Simulation of power equipment;
Methods in diagnostics of electrical insulation;
Application of signal, image processing and artificial intelligence to diagnostics of electrical insulation;
DC Diagnostics, i.e., methods for monitoring electrical insulation in HVDC grids, cables, transformers, converters, breakers, substations, lines, insulators, etc.

Prof. Dr. Xuetong Zhao
Guest Editor

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 250 words) can be sent to the Editorial Office for assessment.

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

fault diagnostics
power transformers
power cable
oil-paper insulation
simulation
detection technology and methods

Benefits of Publishing in a Special Issue

Ease of navigation: Grouping papers by topic helps scholars navigate broad scope journals more efficiently.
Greater discoverability: Special Issues support the reach and impact of scientific research. Articles in Special Issues are more discoverable and cited more frequently.
Expansion of research network: Special Issues facilitate connections among authors, fostering scientific collaborations.
External promotion: Articles in Special Issues are often promoted through the journal's social media, increasing their visibility.
Reprint: MDPI Books provides the opportunity to republish successful Special Issues in book format, both online and in print.

Further information on MDPI's Special Issue policies can be found here.

Published Papers (3 papers)

Download All Papers

Order results

Result details

Show export options Show export options

Select all

Export citation of selected articles as:

Research

23 pages, 2593 KB

Open AccessArticle

Analysis Method of Operating Characteristics and Optimal Arrangement of 500 KV Homopolar Parallel Cables

by Guoyan Chen, Min Zhu, Haisheng Shu, Jian Chi and Wencong Chen

Energies 2026, 19(9), 2145; https://doi.org/10.3390/en19092145 - 29 Apr 2026

Viewed by 204

Abstract

The normal operational characteristics of power cables are a crucial foundation for developing their protection devices. To analyze the current and voltage characteristics of parallel cable lines, the parameter matrix of the phase-aligned parallel cable lines is first established based on Carson’s formula. The metal sheath is treated as a general line, considering its self-inductance and mutual inductance with the core loop, and its sheath circulating current is calculated. Then, the relationship between line voltage and current is established, and the effect of the sheath circulating current is equivalently incorporated into the line’s phase impedance matrix. A π-type equivalent circuit of the cable line is established, from which the operational parameters of the phase-aligned parallel cables are calculated. Indicators measuring the operational characteristics of phase-aligned parallel operation—sheath circulating current, imbalance, carrying capacity, and voltage deviation—are introduced, and the optimal arrangement is determined using the analytic hierarchy process. This study integrates Carson’s formula for impedance modeling and fuzzy AHP for multi-criteria optimization, addressing gaps in single-indicator approaches. The proposed method identifies the three-phase vertical layout as optimal, improving ampacity by 10% and reducing sheath circulating current by 28%, offering direct guidance for 500 kV cable projects. Full article

(This article belongs to the Special Issue Research on Power Transformers, Power Cable, High Voltage and Insulation Technology)

► Show Figures

Figure 1

15 pages, 2122 KB

Open AccessArticle

Effects of Localized Overheating on the Particle Size Distribution and Morphology of Impurities in Transformer Oil

by Shangquan Feng, Ruijin Liao, Lijun Yang, Chen Chen and Xinxi Yu

Energies 2025, 18(24), 6566; https://doi.org/10.3390/en18246566 - 16 Dec 2025

Viewed by 480

Abstract

Power transformers are critical components of power grids, and their operational status characterization and fault diagnosis are crucial for power system reliability. Oil quality assessment is a crucial method for determining transformer status, and the detection of impurity particles in oil has historically been a key approach. However, recent field tests have revealed the presence of numerous impurity particles less than 5 μm in transformer oil. Current power standards do not address these micron-sized particles, and their sources and mechanisms of action are largely unresolved. Therefore, this paper designed a localized overheating experiment, incorporating microflow imaging technology, to investigate the generation patterns of impurity particles under localized overheating and their quantitative correlation with heat. Field oil samples were also collected and tested to further explore the potential application of these micron-sized particles in transformer overheating assessment. The research results show that insulating oil can decompose and produce impurity particles at temperatures as low as 140 °C. When the temperature is below 140 °C, the number of particles at different heat levels is not significantly different from that of the non-overheated oil sample. However, when the temperature exceeds 140 °C, the number of particles increases significantly with increasing heat. Among the generated particles, particles with a diameter of less than 5 μm account for over 50% of the total number, and their number increases significantly with increasing heat. Their morphology is characterized by a smooth, regular, and spherical shape. Field test results of overheated oil samples are consistent with laboratory tests. Micron-sized particles are highly sensitive to changes in overheating conditions and have the potential to be used as a new characteristic parameter of transformer overheating conditions. In summary, this paper reveals the formation mechanism of impurity particles in insulating oil under localized overheating conditions. It was found that insulating oil can also decompose and generate impurity particles at 140 °C, with the pyrolysis products mainly consisting of particles smaller than 5 μm in diameter, which are not currently considered a concern in existing standards. Further research indicates that these micron-sized particles exhibit high sensitivity to changes in overheating conditions, demonstrating potential application value as a novel characteristic parameter of transformer overheating. Full article

(This article belongs to the Special Issue Research on Power Transformers, Power Cable, High Voltage and Insulation Technology)

► Show Figures

Figure 1

18 pages, 3215 KB

Open AccessArticle

A Study on the Optimization Design of Power System Winding Structure Equipment Based on NSGA-II

by Xuelei Wang, Longlong Li, Jian Wang, Qingdong Zhu, Zhaoliang Gu and Mengzhao Zhu

Energies 2025, 18(18), 5001; https://doi.org/10.3390/en18185001 - 20 Sep 2025

Viewed by 705

Abstract

As a key component for maintaining the efficient and stable operation of flexible DC transmission systems, the arm reactor often suffers from uneven loss distribution and localized overheating in its windings due to the superimposed AC and DC currents, which adversely affects its operational lifespan. Furthermore, arm reactors are frequently deployed in offshore environments for long-distance, high-capacity power transmission, imposing additional requirements on energy utilization efficiency and seismic resistance. To address these challenges, this study proposes an optimization design method for arm reactors based on a triple-constraint mechanism of “equal resistive voltage–equal loss density–equal encapsulation temperature rise,” aiming to achieve “low loss–low temperature rise–low weight.” First, an equivalent electromagnetic model of the arm reactor under combined AC and DC operating conditions is established to analytically calculate the self- and mutual-inductance-distribution characteristics between winding layers and the loss distribution across windings. The calculated losses are then applied as heat sources in a fluid–thermal coupling method to compute the temperature field of the arm reactor. Next, leveraging a Kriging surrogate model to capture the relationship between the winding temperature rise in the bridge-arm reactor and the loss density, encapsulation width, encapsulation height, and air duct width, the revised analytical expression reduces the temperature rise error from 43.74% to 11.47% compared with the traditional empirical formula. Finally, the triple-constraint mechanism of “equal resistive voltage–equal loss density–equal encapsulation temperature rise” is proposed to balance interlayer current distribution, suppress total loss generation, and limit localized hotspot formation. A prototype constructed based on the optimized design demonstrates a 44.51% reduction in total loss, a 39.66% decrease in hotspot temperature rise, and a 24.83% reduction in mass while maintaining rated inductance, validating the effectiveness of the proposed design algorithm. Full article

(This article belongs to the Special Issue Research on Power Transformers, Power Cable, High Voltage and Insulation Technology)

► Show Figures

Journal Menu

Journal Browser

Research on Power Transformers, Power Cable, High Voltage and Insulation Technology

Share This Special Issue

Special Issue Editor

Special Issue Information

Keywords

Benefits of Publishing in a Special Issue

Published Papers (3 papers)

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI