The influence of ultrasound signal parameters on sonoluminescence light intensity

2013 ◽  
Vol 62 (4) ◽  
pp. 605-612
Author(s):  
Marek Szmechta ◽  
Tomasz Boczar ◽  
Dariusz Zmarzły
Keyword(s):  
Acoustic Emission ◽  
Acoustic Waves ◽  
Power Transformer ◽  
Electrical Power ◽  
Partial Discharges ◽  
Research Project ◽  
Insulation Systems ◽  
Secondary Phenomenon ◽  
New Research ◽  
The Relationship

Abstract Topics of this article concern the study of the fundamental nature of the sonoluminescence phenomenon occurring in liquids. At the Institute of Electrical Power Engineering at Opole University of Technology the interest in that phenomenon known as secondary phenomenon of cavitation caused by ultrasound became the genesis of a research project concerning acoustic cavitation in mineral insulation oils in which a number of additional experiments performed in the laboratory aimed to determine the influence of a number of acoustic parameters on the process of the studied phenomenona. The main purpose of scientific research subject undertaken was to determine the relationship between the generation of partial discharges in high-voltage power transformer insulation systems, the issue of gas bubbles in transformer oils and the generated acoustic emission signals. It should be noted that currently in the standard approach, the phenomenon of generation of acoustic waves accompanying the occurrence of partial discharges is generally treated as a secondary phenomenon, but it can also be a source of many other related phenomena. Based on our review of the literature data on those referred subjects taken, it must be noted, that this problem has not been clearly resolved, and the description of the relationship between these phenomena is still an open question. This study doesn’t prove all in line with the objective of the study, but can be an inspiration for new research project in the future in this topic. Solution of this problem could be a step forward in the diagnostics of insulation systems for electrical power devices based on non-invasive acoustic emission method.

scholarly journals Radiation in the Optical and UHF Range Emitted by Partial Discharges

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4334 ◽  
Author(s):  
Michał Kozioł ◽  
Łukasz Nagi ◽  
Michał Kunicki ◽  
Ireneusz Urbaniec
Keyword(s):  
Electromagnetic Waves ◽  
Electrical Power ◽  
Partial Discharges ◽  
Radio Waves ◽  
Insulation Systems ◽  
Surface Discharges ◽  
High Voltage Insulation ◽  
Solid Dielectrics ◽  
Electrode Systems ◽  
Optical Spectrophotometry

This paper presents the results of analysis of a solid dielectric’s influence on the phenomena associated with the signals emitted by surface partial discharges. Three types of electrode systems were tested, in which solid dielectrics made of pressboard, Teflon, and glass were used. The emission of such signals as radio waves in the Ultra high frequency (UHF) range and optical radiation was analyzed. The measurements were carried out in the insulation systems most commonly used in electrical power equipment, i.e., mineral oil and air. UHF and optical spectrophotometry methods were used to register the emitted signals. The obtained results indicate that the type of material from which the dielectric solid is made may have a potential impact on some ranges of emitted electromagnetic waves during the surface electrical discharges. The research topic undertaken is important in issues associated with high-voltage insulation systems and in particular with surface discharges, which are often the cause of their damage.

scholarly journals Study on Descriptors of Acoustic Emission Signals Generated by Partial Discharges under Laboratory Conditions and in On-Site Electrical Power Transformer

2016 ◽  
Vol 41 (2) ◽  
pp. 265-276 ◽  
Author(s):  
Michał Kunicki ◽  
Andrzej Cichoń ◽  
Sebastian Borucki
Keyword(s):  
Acoustic Emission ◽  
Power Transformer ◽  
Electrical Power ◽  
High Sensitivity ◽  
Laboratory Research ◽  
Time Frequency ◽  
Laboratory Conditions ◽  
Set Up ◽  
Point To Point ◽  
Ae Signals

Abstract An acoustic emission method (AE) is widespread and often applied for partial discharge (PD) diagnostics, mainly due to its ease of application as well as noninvasiveness and relatively high sensitivity. This paper presents comparative analysis of AE signals measurement results archived under laboratory conditions as well as on-site actual AE signals generated by inside PDs in electrical power transformer during its normal service. Three different PD model sources are applied for laboratory research: point to point, multipoint to plate and surface type. A typical measuring set up commonly used for on-site transformer PD diagnostics is provided for the laboratory tasks: piezoelectric joint transducer, preamplifier, amplifier and measuring PC interface. During the on-site research there are three measuring tracks applied simultaneously. Time domain, time-frequency domain and statistical tools are used for registered AE signals analysis. A number of descriptors are proposed as a result of the analysis. In the paper, at- tempt of AE signals descriptors, archived under laboratory condition application possibilities for on-site PD diagnostics of power transformers during normal service is made.

scholarly journals Influence of additional dielectric coatings on the electrode surfaces on selected parameters of acoustic emission signals in high-voltage gas insulation systems

2021 ◽  
Author(s):  
Arkadiusz Dobrzycki ◽  
Władysław Opydo ◽  
Sebastian Zakrzewski
Keyword(s):  
Acoustic Emission ◽  
High Voltage ◽  
Single Pulse ◽  
Partial Discharges ◽  
Chamber Pressure ◽  
Electrode Surfaces ◽  
Dielectric Coatings ◽  
Signal Parameters ◽  
Insulation Systems ◽  
High Voltage Insulation

AbstractThe paper is devoted to the study of impact of additional dielectric coatings placed on the surface of the electrodes on the operation of a high-voltage insulation system with air as insulating medium. The study mainly focused on measurement of partial discharges (PDs) with the use of acoustic emission method. Tests were conducted in various levels of chamber pressure. Applicable parameters of recorded signals were analyzed with the use of applications developed in the environment of MATLAB software. The results of analyses clearly show that presence of additional coatings has impact on signal parameters and thus indirectly on PDs. The use of coatings reduces the duration of a single pulse (event) and increases its amplitude. Furthermore, the influence of degradation of the coating caused by individual discharges on the values of the analyzed parameters was analyzed. The study has shown, however, that this effect is negligible.

scholarly journals Analysis of Internal Overvoltages in Transformer Windings during Transients in Electrical Networks

Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2644 ◽  
Author(s):  
Jakub Furgał ◽  
Maciej Kuniewski ◽  
Piotr Pająk
Keyword(s):  
Power Systems ◽  
Electromagnetic Waves ◽  
Power Transformer ◽  
Electrical Power ◽  
Operating Conditions ◽  
Electromagnetic Transients ◽  
Electrical Network ◽  
Electrical Networks ◽  
Insulation Systems ◽  
The Impact

Due to the increasing requirements for the reliability of electrical power supply and associated apparatus, it is necessary to provide a detailed analysis of the overvoltage risk of power transformer insulation systems and equipment connected to their terminals. Exposure of transformer windings to overvoltages is the result of the propagation condition of electromagnetic waves in electrical networks and transformer windings. An analysis of transformer winding responses to transients in power systems is of particular importance, especially when protection against surges by typical overvoltage protection systems is applied. The analysis of internal overvoltages in transformers during a typical transient related to switching operations and selected failures is of great importance, particularly to assess the overvoltage exposure of insulation systems in operating conditions. The random nature of overvoltage phenomena in electrical networks implies the usage of computer simulations for the analysis of overvoltage exposures of electrical devices in operation. This article presents the analysis of the impact of transient phenomena in a model of a medium-voltage electrical network during switching operations and ground faults on overvoltages in the internal insulation systems of transformer windings. The basis of the analysis is simulations of overvoltages in the windings, made in the Electromagnetic Transients Program/Alternative Transients Program (EMTP/ATP) using a model with lumped parameters of transformer windings. The analysis covers the impact of the cable line length and the ground fault resistance value on internal overvoltage distributions.

scholarly journals Application of Acoustic Emission and Thermal Imaging to Test Oil Power Transformers

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5955
Author(s):  
Franciszek Witos ◽  
Aneta Olszewska ◽  
Zbigniew Opilski ◽  
Agnieszka Lisowska-Lis ◽  
Grzegorz Szerszeń
Keyword(s):  
Acoustic Emission ◽  
Thermal Imaging ◽  
Research Method ◽  
Power Transformer ◽  
Partial Discharges ◽  
Power Transformers ◽  
Imaging Studies ◽  
Ir Radiation ◽  
Side Walls ◽  
Ae Signals

In this paper, the research methodology and the results of the analysis carried out using the acoustic emission (AE) and thermal imaging for a selected oil power transformer are presented. The basis for the research, by means of the AE method, was the author’s patented research method. The AE descriptor maps on the side walls of the tested transformer along with the location of areas with increased AE activity and an analysis of the properties of AE signals recorded at the measurement points located in these areas have been performed. The results showed no partial discharges that could threaten further operation of the tested transformer as well as three areas where increased magnetoacoustic emission occurred. Thermal imaging studies were carried out in the 7.5 μm < λ < 13 μm band. Three areas were located on the calculated thermograms: the entire upper surface of the transformer tank and two areas on the side walls of the tested transformer in which increased IR radiation occurred. The results of the analysis of the research results for the two methods correspond with each other, having a common part, and complement each other giving a broader description of studied phenomena.

scholarly journals Consumption and Retail in Urban Spaces: Studies on Italy and Catalonia

2021 ◽  
pp. 7-12
Author(s):  
Rosario Sommella
Keyword(s):  
Case Studies ◽  
Research Agenda ◽  
Urban Spaces ◽  
Urban Landscapes ◽  
Special Issue ◽  
Research Project ◽  
Scientific Results ◽  
New Research ◽  
The Relationship ◽  
The City

The article, based on the scientific results of the last phase of the project “Retail, Consumption, and the City: Practices, Planning and Governance for Urban Inclusion, Resilience and Sustainability”, proposes further reflections on the changing urban landscapes of retail and consumption through studies on Italy and Catalonia. This stage of the research project has been aimed at investigating – through specific in-depth studies (thematic or related to case studies) – aspects not adequately dealt with in the published volumes of the seven research units, or even to take inspiration from themes and cases already dealt with to advance in a reflection that could contribute to build a further piece of a new research agenda on retail, consumption, and the city. By cross-referencing descriptive evidence and theoretical reflections, the article traces the main themes of this special issue, with regard to the evolutionary and, in some cases, analytical trajectories starting as from the different case studies analyzed, all aimed at reflecting on the relationship between consumption, retail and urban spaces in Italy and Catalonia at different scales.

INNOVATION CAPABILITY, ABSORPTIVE CAPACITY AND SMES PERFORMANCE IN PAKISTAN: THE MODERATING EFFECT OF BUSINESS STRATEGY

2018 ◽  
Vol 13 (Number 2) ◽  
pp. 1-11
Author(s):  
Muhammad Zulqarnain Arshad ◽  
Darwina Arshad
Keyword(s):  
Economic Growth ◽  
Absorptive Capacity ◽  
Business Strategy ◽  
Innovation Capability ◽  
Research Directions ◽  
Conceptual Paper ◽  
And Performance ◽  
New Research ◽  
The Relationship ◽  
Crucial Part

The small and medium-sized enterprises (SMEs) play a crucial part in county’s economic growth and a key contributor in country’s GDP. In Pakistan SMEs hold about 90 percent of the total businesses. The performance of SMEs depends upon many factors. The main aim for the research is to examine the relationship between Innovation Capability, Absorptive Capacity and Performance of SMEs in Pakistan. This conceptual paper also extends to the vague revelation on Business Strategy in which act as a moderator between Innovation Capability, Absorptive Capacity and SMEs Performance. Conclusively, this study proposes a new research directions and hypotheses development to examine the relationship among the variables in Pakistan’s SMEs context.

FBI and Religion

2017 ◽  
Keyword(s):  
Religious Orientation ◽  
Religious Communities ◽  
Academic Scholarship ◽  
History Of ◽  
Interdisciplinary Assessment ◽  
Civic Religion ◽  
New Research ◽  
The Relationship ◽  
The Way

This volume is an interdisciplinary assessment of the relationship between religion and the FBI. We recount the history of the FBI’s engagement with multiple religious communities and with aspects of public or “civic” religion such as morality and respectability. The book presents new research to explain roughly the history of the FBI’s interaction with religion over approximately one century, from the pre-Hoover period to the post-9/11 era. Along the way, the book explores vexed issues that go beyond the particulars of the FBI’s history—the juxtaposition of “religion” and “cult,” the ways in which race can shape the public’s perceptions of religion (and vica versa), the challenges of mediating between a religious orientation and a secular one, and the role and limits of academic scholarship as a way of addressing the differing worldviews of the FBI and some of the religious communities it encounters.

A strategy to locate partial discharges in power transformers using acoustic emission

2007 ◽  
Vol 1 (05) ◽  
pp. 596-600 ◽  
Author(s):  
Giscard Franceire Cintra Veloso ◽  
◽  
Luiz Eduardo Borges da Silva ◽  
Germano Lambert-Torres
Keyword(s):  
Acoustic Emission ◽  
Partial Discharges ◽  
Power Transformers
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