Research

Jump to: Review

19 pages, 7207 KiB

Open AccessArticle

Improvement of the Electrical Performance of Outdoor Porcelain Insulators by Utilization of a Novel Nano-TiO₂ Coating for Application in Railway Electrification Systems

by Pichai Muangpratoom, Issaraporn Khonchaiyaphum and Wanwilai Vittayakorn

Energies 2023, 16(1), 561; https://0-doi-org.brum.beds.ac.uk/10.3390/en16010561 - 03 Jan 2023

Viewed by 2051

Abstract

The present study aimed to develop the electrical performance of outdoor insulators using a nano-TiO₂ coating for railway electrification systems. The prototype design of porcelain insulators with normal coatings and using a nano-TiO₂ coating is based on IEC 60815-1. The first [...] Read more.

The present study aimed to develop the electrical performance of outdoor insulators using a nano-TiO₂ coating for railway electrification systems. The prototype design of porcelain insulators with normal coatings and using a nano-TiO₂ coating is based on IEC 60815-1. The first test was performed to measure the low-frequency flashover AC voltage under both dry and wet conditions. In addition, the other test was conducted to measure the lightning impulse critical-flashover voltage at positive and negative polarity under dry-normal and wet-contaminated conditions. X-ray diffraction (X-RD) and Scanning electron microscopy (SEM) were used to examine the micro surface and show that the nano-TiO₂ coating was adhered to the surface of the outdoor porcelain insulator and exists in an amorphous state. Additionally, it was observed and discovered that scattered nano-TiO₂ strengthens the glassy matrix and creates a sturdy barrier that causes flashover voltage to be reduced under conditions of high dielectric strength. Nanostructured ceramic formulations outperform ordinary porcelain in terms of breakdown voltage strength, particularly for the insulators’ low-frequency flashover performances under dry and wet test conditions. However, a significant change in the lightning impulse critical-flashover voltage characteristics is observed and is not much better when adding the nano-TiO₂ coating to the porcelain insulators. Full article

(This article belongs to the Special Issue Testing, Monitoring and Diagnostic of High Voltage Equipment)

► Show Figures

Figure 1

14 pages, 4401 KiB

Open AccessArticle

Experimental Study and Modeling of the Effect of ESDD/NSDD on AC Flashover of SiR Outdoor Insulators

by Mohammed El Amine Slama, Adnan Krzma, Maurizio Albano and Abderrahmane Manu Haddad

Energies 2022, 15(10), 3782; https://0-doi-org.brum.beds.ac.uk/10.3390/en15103782 - 20 May 2022

Cited by 4 | Viewed by 1744

Abstract

Pollution flashover occurs when soluble and nonsoluble materials cover the surface of an insulator, and this may ultimately cause a reduction in its performance. In this paper, the common type of sodium chloride (NaCl) was used as a soluble pollutant (ESDD) and kaolin [...] Read more.

Pollution flashover occurs when soluble and nonsoluble materials cover the surface of an insulator, and this may ultimately cause a reduction in its performance. In this paper, the common type of sodium chloride (NaCl) was used as a soluble pollutant (ESDD) and kaolin as a nonsoluble pollutant (NSDD). Samples of silicone rubber (SiR) insulators were selected for this study and fabricated at the Advanced High Voltage Engineering Research Centre (AHIVEC) at Cardiff University. The samples were preconditioned and polluted according to standard specifications. Additionally, the AC voltage ramp technique was used to achieve flashover (FOV) voltage with different pollution levels. The aim of this work was to investigate the effect of nonsoluble materials on flashover characteristics to understand their interaction with dry-band arcs by using FOV electrical equations and experimental data. The test results show that the FOV voltage of the silicone rubber insulator substantially decreased with the increase in both ESDD and NSDD values. It was also identified from these results that the dry-band arcs were considerably influenced by both ESDD and NSDD levels. This impact can be quantified by determining the variation of discharge parameters (N, n). Based on the FOV equations and experimental data, a mathematical model was suggested, taking into account the effect of both ESDD and NSDD. Full article

(This article belongs to the Special Issue Testing, Monitoring and Diagnostic of High Voltage Equipment)

► Show Figures

Figure 1

11 pages, 3558 KiB

Open AccessArticle

Electric Field Distribution and AC Breakdown Characteristics of Polluted Novel Lightning Protection Insulator under Icing Conditions

by Jiazheng Lu, Jianping Hu, Zhen Fang, Xinhan Qiao and Zhijin Zhang

Energies 2021, 14(22), 7493; https://0-doi-org.brum.beds.ac.uk/10.3390/en14227493 - 09 Nov 2021

Cited by 7 | Viewed by 1446

Abstract

As a result of lightning strikes, pollution, and ice, overhead distribution wires might be short-circuited and trip. As a result, researchers have developed a new lightning protection composite insulator. There is still a need to test its pollution and icing performance. Based on [...] Read more.

As a result of lightning strikes, pollution, and ice, overhead distribution wires might be short-circuited and trip. As a result, researchers have developed a new lightning protection composite insulator. There is still a need to test its pollution and icing performance. Based on the finite element and field test method, this paper studies the electric field distribution and AC (Alternating Current) breakdown characteristics of polluted novel lightning protection insulators under icing conditions. Firstly, the finite element calculated results show that this novel insulator’s electric field distribution is different from that of a conventional insulator. The locations with sizeable electric fields are located in the insulation section, and the electric field in the arrester section is tiny. In addition, when the insulator surface is covered with ice, there is an increase in the electric field along the surface and pin electrodes. Compared with the dry conditions, when there is an ice layer and icicle, electric field peaks increase by 48.85% and 46.08%, respectively. Secondly, the test results show that there are three types of arc paths in different pollution levels. The arc paths are related to ESDD (equivalent salt deposit density) under icing conditions. U_f shows a downward trend with increased pollution levels, and the maximum flashover voltage is 2.70 times more than the minimum. Finally, four fitting methods are proposed in this paper. After comparing the goodness of fit of different functions, the quadratic function and negative power function with the constant term are recommended as empirical formulas for calculating flashover voltage of novel insulators under icing conditions in different pollution levels. The research results of this paper have a specific guiding role for the selection of the external insulation of transmission lines and structural optimization of novel insulators. Full article

(This article belongs to the Special Issue Testing, Monitoring and Diagnostic of High Voltage Equipment)

► Show Figures

Figure 1

36 pages, 9484 KiB

Open AccessArticle

Frequency Resolved Partial Discharges Based on Spectral Pulse Counting

by Anderson J. C. Sena, Rodrigo M. S. de Oliveira and Júlio A. S. do Nascimento

Energies 2021, 14(21), 6864; https://0-doi-org.brum.beds.ac.uk/10.3390/en14216864 - 20 Oct 2021

Cited by 1 | Viewed by 1662

Abstract

A partial discharge (PD) classification methodology based counting PD pulses in the spectral domain is proposed and presented in this paper. The spectral counting data are processed using the proposed PD Spectral Pulse Counting Mapping technique (PD-SPCM), which leads to a Frequency-Resolved Partial [...] Read more.

A partial discharge (PD) classification methodology based counting PD pulses in the spectral domain is proposed and presented in this paper. The spectral counting data are processed using the proposed PD Spectral Pulse Counting Mapping technique (PD-SPCM), which leads to a Frequency-Resolved Partial Discharges (FRPD) map. The proposed map is then used for PD detection and classification. In this work, corona and slot FRPDs are presented in frequency bands up to 500 MHz, obtained from laboratory measurements performed using two hydro-generator stator bars. The electromagnetic signals from the PDs were captured using a patch antenna designed for this purpose and a spectral analyzer. The corona and slot PDs were chosen because one can be mistakenly classified as the other because they may present similar Phase Resolved PD (PRPD) maps and may occupy shared spectral bands. Furthermore, corona and slot PDs can occur concurrently. The obtained results show that the corona and slot PDs can be properly identified using the developed methodology, even when they occur simultaneously. This is possible because, as it is experimentally demonstrated, corona and slot PDs have appreciable levels of spectral pulse counting in particular bands of the frequency spectrum. Full article

(This article belongs to the Special Issue Testing, Monitoring and Diagnostic of High Voltage Equipment)

► Show Figures

Graphical abstract

20 pages, 5839 KiB

Open AccessArticle

Failure Diagnosis and Root-Cause Analysis of In-Service and Defective Distribution Transformers

by Saravanakumar Arumugam

Energies 2021, 14(16), 4997; https://0-doi-org.brum.beds.ac.uk/10.3390/en14164997 - 14 Aug 2021

Cited by 5 | Viewed by 2718

Abstract

Diagnostic data of transformers are essential in determining their integrity and to estimate their reliability. Such diagnostic data is not available for distribution transformers as only meagre attempts are made to accumulate this information. The reason for lack of such attention is attributed [...] Read more.

Diagnostic data of transformers are essential in determining their integrity and to estimate their reliability. Such diagnostic data is not available for distribution transformers as only meagre attempts are made to accumulate this information. The reason for lack of such attention is attributed to the compromise made to meet financial constraints and cost-cutting measures. It is needless to emphasize the significance of these diagnostic data in evading premature failures and enhancing the accuracy of the maintenance program. Overall, the concepts of diagnostic methods are well defined regarding power transformers, but cannot be extended to distribution transformers. This paper attempts to fill this gap by measuring the diagnostic data from in-service and defective distribution transformers. For this purpose, eight transformers (six in-service, two defective) showing deviations in their diagnostic status were selected from a group. As per their kVA rating and operating status, the chosen transformers were categorized into three sets and their integrity of insulation and winding-core arrangement were analyzed. Later, the root-cause analysis was performed on defective transformers to understand their failure reasons and possibilities to evade them. The pertinent data obtained are quite valuable for making decisions regarding reliability-oriented maintenance and for extending its potential in the distributed generation. Full article

(This article belongs to the Special Issue Testing, Monitoring and Diagnostic of High Voltage Equipment)

► Show Figures

Figure 1

18 pages, 4063 KiB

Open AccessArticle

Temperature Distribution in the Insulation System of Condenser-Type HV Bushing—Its Effect on Dielectric Response in the Frequency Domain

by Krzysztof Walczak and Jaroslaw Gielniak

Energies 2021, 14(13), 4016; https://0-doi-org.brum.beds.ac.uk/10.3390/en14134016 - 03 Jul 2021

Cited by 6 | Viewed by 4135

Abstract

HV bushings are an important part of the equipment of large power transformers, responsible for their many serious (including catastrophic) failures. Their proper exploitation needs to apply correct and reliable diagnostics, e.g., the use of dielectric response methods, that take into account their [...] Read more.

HV bushings are an important part of the equipment of large power transformers, responsible for their many serious (including catastrophic) failures. Their proper exploitation needs to apply correct and reliable diagnostics, e.g., the use of dielectric response methods, that take into account their specific construction and working conditions. In this article, based on laboratory tests carried out on a real bushing, it has been shown that the significant temperature distribution within its core significantly affects the shape of the dielectric response of its insulation; therefore, the approach to its modeling should be changed. Hence, a new method for interpreting the results, using the so-called the 2XY model, is proposed. Subsequently, based on the measurements made on the insulators in operation, a new modeling method was verified. In conclusion, it can be stated that the 2XY model significantly improves the reliability of the dielectric response analysis, which should be confirmed in the future by tests on withdrawn and revised insulators. Full article

(This article belongs to the Special Issue Testing, Monitoring and Diagnostic of High Voltage Equipment)

► Show Figures

Figure 1

Review

Jump to: Research

31 pages, 10496 KiB

Open AccessReview

A Review of Icing and Anti-Icing Technology for Transmission Lines

by Zhijin Zhang, Hang Zhang, Song Yue and Wenhui Zeng

Energies 2023, 16(2), 601; https://0-doi-org.brum.beds.ac.uk/10.3390/en16020601 - 04 Jan 2023

Cited by 14 | Viewed by 4879

Abstract

This paper reviews the application of various advanced anti-icing and de-icing technologies in transmission lines. Introduces the influence of snowing and icing disasters on transmission lines, including a mechanical overload of steel towers, uneven icing or de-icing at different times, Ice-covered conductors galloping [...] Read more.

This paper reviews the application of various advanced anti-icing and de-icing technologies in transmission lines. Introduces the influence of snowing and icing disasters on transmission lines, including a mechanical overload of steel towers, uneven icing or de-icing at different times, Ice-covered conductors galloping and icing flashover of insulators, as well as the icing disasters of transmission lines around the world in recent years. The formation of various icing categories on transmission lines, as well as the effect of meteorological factors, topography, altitude, line direction, suspension height, shape, and electric field on ice-covered transmission lines, are all discussed in this study. The application of various advanced anti/de-icing technologies and their advantages and disadvantages in power transmission lines are summarized. The anti/de-icing of traditional mechanical force, AC/DC short-circuit ice melting, and corona effect is introduced. Torque pendulum and diameter-expanded conductor (DEC) have remarkable anti-icing effects, and the early investment resources are less, the cost is low, and the later maintenance is not needed. In view of some deficiencies of AC and DC ice melting, the current transfer intelligent ice melting device (CTIIMD) can solve the problem well. The gadget has a good effect and high reliability for de-icing conductors in addition to being compact and inexpensive. The application of hydrophobic materials and heating coatings on insulators has a certain anti-icing effect, but the service life needs further research. Optimizing the shed’s construction and arranging several string kinds on the insulators is advisable to prevent icing and the anti-icing flashover effect. In building an insulator, only a different shed layout uses non-consumption energy. Full article

(This article belongs to the Special Issue Testing, Monitoring and Diagnostic of High Voltage Equipment)

► Show Figures

Figure 1

32 pages, 6245 KiB

Open AccessReview

Deep Learning in High Voltage Engineering: A Literature Review

by Sara Mantach, Abdulla Lutfi, Hamed Moradi Tavasani, Ahmed Ashraf, Ayman El-Hag and Behzad Kordi

Energies 2022, 15(14), 5005; https://0-doi-org.brum.beds.ac.uk/10.3390/en15145005 - 08 Jul 2022

Cited by 16 | Viewed by 3526

Abstract

Condition monitoring of high voltage apparatus is of much importance for the maintenance of electric power systems. Whether it is detecting faults or partial discharges that take place in high voltage equipment, or detecting contamination and degradation of outdoor insulators, deep learning which [...] Read more.

Condition monitoring of high voltage apparatus is of much importance for the maintenance of electric power systems. Whether it is detecting faults or partial discharges that take place in high voltage equipment, or detecting contamination and degradation of outdoor insulators, deep learning which is a branch of machine learning has been extensively investigated. Instead of using hand-crafted manual features as an input for the traditional machine learning algorithms, deep learning algorithms use raw data as the input where the feature extraction stage is integrated in the learning stage, resulting in a more automated process. This is the main advantage of using deep learning instead of traditional machine learning techniques. This paper presents a review of the recent literature on the application of deep learning techniques in monitoring high voltage apparatus such as GIS, transformers, cables, rotating machines, and outdoor insulators. Full article

(This article belongs to the Special Issue Testing, Monitoring and Diagnostic of High Voltage Equipment)

► Show Figures

Figure 1

26 pages, 4358 KiB

Open AccessReview

Dielectric Strength of Polymeric Solid–Solid Interfaces under Dry-Mate and Wet-Mate Conditions

by Emre Kantar

Energies 2021, 14(23), 8067; https://0-doi-org.brum.beds.ac.uk/10.3390/en14238067 - 02 Dec 2021

Cited by 4 | Viewed by 1906

Abstract

One of the most important causes of insulation system failure is the breakdown of the interface between two solid dielectrics; understanding the mechanisms governing this breakdown phenomenon is therefore critical. To that end, investigating and reviewing the practical limitations of the electrical breakdown [...] Read more.

One of the most important causes of insulation system failure is the breakdown of the interface between two solid dielectrics; understanding the mechanisms governing this breakdown phenomenon is therefore critical. To that end, investigating and reviewing the practical limitations of the electrical breakdown strength of solid–solid interfaces present in insulating components is the primary objective of this work. The published literature from experimental and theoretical studies carried out in order to scrutinize the effects of the presence of solid–solid interfaces is investigated and discussed, considering macro, micro, and nano-scale characteristics. The reviewed literature suggests that solid–solid interfaces in accessories have non-uniform distributions of electrical fields within them in comparison to cables, where the distribution is mostly radial and symmetrical. Many agree that the elastic modulus (elasticity), radial/tangential pressure, surface smoothness/roughness, and dielectric strength of the ambient environment are the main parameters determining the tangential AC breakdown strength of solid–solid interfaces. Full article

(This article belongs to the Special Issue Testing, Monitoring and Diagnostic of High Voltage Equipment)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Testing, Monitoring and Diagnostic of High Voltage Equipment

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Related Special Issue

Published Papers (9 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI