Richard Janura - Academia.edu (original) (raw)

Papers by Richard Janura

Paper deals with the analysis of thermal processes in oil power transformers. By means of the mat... more Paper deals with the analysis of thermal processes in oil power transformers. By means of the mathematical analysis and experimental measurements it is possible to diagnose of distribution oil transformers in terms of mechanical strength of winding. Analysis of warming at varying loads is very importance, since allows determining the load capacity and overload of the transformer under various operating conditions and respecting the variable ambient temperature.

Article presents effects caused by electromagnetic forces on the transformer windings. It shows d... more Article presents effects caused by electromagnetic forces on the transformer windings. It shows dimensions, direction and of course caused mechanical stress. Equation shows basic dependencies of these mechanical forces created in the transformer windings. The last part of the article is focused to the simulation method which shows the mechanical stress caused by the short circuit-currents. This method is preferred for analysis of power transformer.

This article presents electromagnetic effects on transformer winding. It shows dimension of force... more This article presents electromagnetic effects on transformer winding. It shows dimension of force causing by short-circuits and how this force is created. In graphs are shown basics dependences for transformer and its dimension (its power) and mechanical forces. In the next is dealing with transient actions at overvoltages. There is showed how can overvoltages be created and how long overvoltages are take time. Third part of article is focused on measurement method. This method is preferred for testing big transformer. In method are described frequency ranges and possible exploitation of this method. Conclusion is proposal for next leading of this issue.

Metrology and Measurement Systems, Dec 1, 2016

The paper presents theoretical and experimental analyses of a possible effect of the short-circui... more The paper presents theoretical and experimental analyses of a possible effect of the short-circuit forces on the transformer winding. The first part of the paper is focused on creation and activity of the radial and axial forces during a short circuit. It shows dimensions, direction and − of course − the resulting mechanical stress. The presented equation shows basic dependencies of these mechanical forces created in the transformer winding. Finally, the paper presents experimental methods of diagnosing and analysing the effects of short-circuit forces on the transformer winding.

This article is focused about for electronic proposal measuring system of moisture analysis by re... more This article is focused about for electronic proposal measuring system of moisture analysis by return voltage method (RVM) for power oil transformers. RVM method is wide state specifying method which is not set in standards but in many cases is a method which is determining a clear and exact result. The results have mainly shows moisture content, content of conductive impurities in oil and degree of aging of paper insulation impact.

Article presents analysis of insulating and mechanical state of transformers considering possible... more Article presents analysis of insulating and mechanical state of transformers considering possible effect of short-circuit currents on the winding. The first part of the article is focused to negative activity thermal and mechanical effects of short-circuit currents. The last part of the article is focused to the simulation method which shows the mechanical stress caused by the short circuit-currents. Finally, the article presents experimental frequency methods of diagnostics for analysis of the short-circuit effects on insulating and mechanical transformer state.

Przegląd Elektrotechniczny, Aug 5, 2015

omawia metody opisujące stan izolacji transformatorów. Przez określenie jej stanu jest poznanie p... more omawia metody opisujące stan izolacji transformatorów. Przez określenie jej stanu jest poznanie pomiarów napięcia powrotnego oraz pomiarów rezystancji izolacji uzwojeń. Metoda pomiaru napięcia powrotnego jest metodą szeroko opisującą stan, która nie jest objęta normami ale w wielu przypadkach umożliwia uzyskanie jasnych i dokładnych wyników. Wyniki przede wszystkim pokazują zawartość wilgoci, zawartość przewodzących zanieczyszczeń w oleju oraz wpływ stopnia starzenia na papier izolacyjny. (Diagnostyka transformatorów z izolacją papierowo-olejową).

This article is focused about for analyse moisture of power oil transformer by proposed electroni... more This article is focused about for analyse moisture of power oil transformer by proposed electronic measuring system. Proposed system use time return voltage method (RVM). In the first sections of the paper is description of electronic proposal for measuring system. In the paper are presented connecting of power supply to the measurement system platform, power supply connecting of switching modules and connecting of high-voltage and rectifier part of the system. In the conclusion are the results which have mainly shows moisture content in distribution transformer.

2016 Diagnostic of Electrical Machines and Insulating Systems in Electrical Engineering (DEMISEE), 2016

Article presents theoretical and experimental analyses of possible effect of short-circuit forces... more Article presents theoretical and experimental analyses of possible effect of short-circuit forces on the transformer windings. The first part of the article is focused to the establishment and activity radial and axial forces during short circuit. It shows dimensions, direction and of course caused mechanical stress. Equation shows basic dependencies of these mechanical forces created in the transformer windings. Finally, the article presents experimental methods of diagnostics for analysis of the short-circuit forces on transformer windings.

2016 Conference on Diagnostics in Electrical Engineering (Diagnostika), 2016

Article presents analysis of insulating and mechanical state of transformers considering possible... more Article presents analysis of insulating and mechanical state of transformers considering possible effect of short-circuit currents on the winding. The first part of the article is focused to negative activity thermal and mechanical effects of short-circuit currents. The last part of the article is focused to the simulation method which shows the mechanical stress caused by the short circuit-currents. Finally, the article presents experimental frequency methods of diagnostics for analysis of the short-circuit effects on insulating and mechanical transformer state.

Measurement Science Review, 2018

The authors describe experimental and theoretical analyses of faults of power transformer winding... more The authors describe experimental and theoretical analyses of faults of power transformer winding. Faults were caused by mechanical effect of short-circuit currents. Measurements of transformer were carried out in high-voltage laboratory. Frequency and time diagnostic methods (method SFRA - Sweep Frequency Response Analysis, impact test) were used for the analyses. Coils of transformer windings were diagnosed by means of the SFRA method and the time impact test. The analyzed methods had a significant sensitivity to a relatively small deformation of coil. In the analysis a new technique for analyzing the effects of short-circuit currents is introduced. This technique is developed for high-voltage transformers (different types of power). The proposed analyses show that it is necessary to analyze the value of short-circuit current. Short-circuit current represents a danger for the operation of the power transformer. The proposed approach can be used for other types of transformers. Mor...

2015 56th International Scientific Conference on Power and Electrical Engineering of Riga Technical University (RTUCON), 2015

Article presents effects caused by electromagnetic forces on the transformer windings. It shows d... more Article presents effects caused by electromagnetic forces on the transformer windings. It shows dimensions, direction and of course caused mechanical stress. Equation shows basic dependencies of these mechanical forces created in the transformer windings. The last part of the article is focused to the simulation method which shows the mechanical stress caused by the short circuit-currents. This method is preferred for analysis of power transformer.

The article discusses the state of transformer insulation. For a more accurate determination of t... more The article discusses the state of transformer insulation. For a more accurate determination of the transformer insulation state are used three methods. The measurement of insulation resistance is the basic method and is set in the standard, value demonstrates the state of total insulation of transformer. Because the determination of moisture content of the paper insulation of transformer is very difficult process and it is necessary take a sample of paper, in this case is used method of return voltage. Return voltage measurement is more complex method and in many cases is determine a clear result very difficult. For evaluation of results have mainly impact moisture content and degree of aging of paper insulation and of course, content of conductive impurities in oil. Because the moisture content in oil is much lower than in the paper, return voltage measurement is used to determine the moisture content in paper insulation only. To confirm the results of return voltage measurement i...

The article discusses the state of transformer insulation. For a more accurate determination of t... more The article discusses the state of transformer insulation. For a more accurate determination of the transformer insulation state are used three methods. The measurement of insulation resistance is the basic method and is set in the standard, value demonstrates the state of total insulation of transformer. Because the determination of moisture content of the paper insulation of transformer is very difficult process and it is necessary take a sample of paper, in this case is used method of return voltage. Return voltage measurement is more complex method and in many cases is determine a clear result very difficult. For evaluation of results have mainly impact moisture content and degree of aging of paper insulation and of course, content of conductive impurities in oil. Because the moisture content in oil is much lower than in the paper, return voltage measurement is used to determine the moisture content in paper insulation only. To confirm the results of return voltage measurement i...

2018 International Conference on Diagnostics in Electrical Engineering (Diagnostika), 2018

This article is focused about for analyse moisture of power oil transformer by proposed electroni... more This article is focused about for analyse moisture of power oil transformer by proposed electronic measuring system. Proposed system use time return voltage method (RVM). In the first sections of the paper is description of electronic proposal for measuring system. In the paper are presented connecting of power supply to the measurement system platform, power supply connecting of switching modules and connecting of high-voltage and rectifier part of the system. In the conclusion are the results which have mainly shows moisture content in distribution transformer.

This article presents electromagnetic effects on transformer winding. It shows dimension of force... more This article presents electromagnetic effects on transformer winding. It shows dimension of force causing by short-circuits and how this force is created. In graphs are shown basics dependences for transformer and its dimension (its power) and mechanical forces. In the next is dealing with transient actions at overvoltages. There is showed how can overvoltages be created and how long overvoltages are take time. Third part of article is focused on measurement method. This method is preferred for testing big transformer. In method are described frequency ranges and possible exploitation of this method. Conclusion is proposal for next leading of this issue.

The article deals with method describing the state of transformer insulation. By the determining ... more The article deals with method describing the state of transformer insulation. By the determining its state is acquainted return voltage measurement and measurement the insulation resistance of windings. Return measurement voltage method is wide state specifying method which is not set in standards but in many cases is a method which is determining a clear and exact result. The results have mainly shows moisture content, content of conductive impurities in oil and degree of aging of paper insulation impact.

This article is focused about for electronic proposal measuring system of moisture analysis by re... more This article is focused about for electronic proposal measuring system of moisture analysis by return voltage method (RVM) for power oil transformers. RVM method is wide state specifying method which is not set in standards but in many cases is a method which is determining a clear and exact result. The results have mainly shows moisture content, content of conductive impurities in oil and degree of aging of paper insulation impact.

The first part of the paper deals with the base information about base measuring methods of trans... more The first part of the paper deals with the base information about base measuring methods of transformer insulating system. The second part of paper deals use of time methods - the method of return voltage measurement (RVM) and method of polarization depolarization current (PDC) for distribution transformer. These methods are used in the analysis of the insulating condition of power transformer with a system of oil-paper. In the other part, the paper presents experimental results of the moisture measurement for a real transformer 22/0.4 kV using time method RVM.

Paper deals with the analysis of thermal processes in oil power transformers. By means of the mat... more Paper deals with the analysis of thermal processes in oil power transformers. By means of the mathematical analysis and experimental measurements it is possible to diagnose of distribution oil transformers in terms of mechanical strength of winding. Analysis of warming at varying loads is very importance, since allows determining the load capacity and overload of the transformer under various operating conditions and respecting the variable ambient temperature.

Article presents effects caused by electromagnetic forces on the transformer windings. It shows d... more Article presents effects caused by electromagnetic forces on the transformer windings. It shows dimensions, direction and of course caused mechanical stress. Equation shows basic dependencies of these mechanical forces created in the transformer windings. The last part of the article is focused to the simulation method which shows the mechanical stress caused by the short circuit-currents. This method is preferred for analysis of power transformer.

This article presents electromagnetic effects on transformer winding. It shows dimension of force... more This article presents electromagnetic effects on transformer winding. It shows dimension of force causing by short-circuits and how this force is created. In graphs are shown basics dependences for transformer and its dimension (its power) and mechanical forces. In the next is dealing with transient actions at overvoltages. There is showed how can overvoltages be created and how long overvoltages are take time. Third part of article is focused on measurement method. This method is preferred for testing big transformer. In method are described frequency ranges and possible exploitation of this method. Conclusion is proposal for next leading of this issue.

Metrology and Measurement Systems, Dec 1, 2016

The paper presents theoretical and experimental analyses of a possible effect of the short-circui... more The paper presents theoretical and experimental analyses of a possible effect of the short-circuit forces on the transformer winding. The first part of the paper is focused on creation and activity of the radial and axial forces during a short circuit. It shows dimensions, direction and − of course − the resulting mechanical stress. The presented equation shows basic dependencies of these mechanical forces created in the transformer winding. Finally, the paper presents experimental methods of diagnosing and analysing the effects of short-circuit forces on the transformer winding.

This article is focused about for electronic proposal measuring system of moisture analysis by re... more This article is focused about for electronic proposal measuring system of moisture analysis by return voltage method (RVM) for power oil transformers. RVM method is wide state specifying method which is not set in standards but in many cases is a method which is determining a clear and exact result. The results have mainly shows moisture content, content of conductive impurities in oil and degree of aging of paper insulation impact.

Article presents analysis of insulating and mechanical state of transformers considering possible... more Article presents analysis of insulating and mechanical state of transformers considering possible effect of short-circuit currents on the winding. The first part of the article is focused to negative activity thermal and mechanical effects of short-circuit currents. The last part of the article is focused to the simulation method which shows the mechanical stress caused by the short circuit-currents. Finally, the article presents experimental frequency methods of diagnostics for analysis of the short-circuit effects on insulating and mechanical transformer state.

Przegląd Elektrotechniczny, Aug 5, 2015

omawia metody opisujące stan izolacji transformatorów. Przez określenie jej stanu jest poznanie p... more omawia metody opisujące stan izolacji transformatorów. Przez określenie jej stanu jest poznanie pomiarów napięcia powrotnego oraz pomiarów rezystancji izolacji uzwojeń. Metoda pomiaru napięcia powrotnego jest metodą szeroko opisującą stan, która nie jest objęta normami ale w wielu przypadkach umożliwia uzyskanie jasnych i dokładnych wyników. Wyniki przede wszystkim pokazują zawartość wilgoci, zawartość przewodzących zanieczyszczeń w oleju oraz wpływ stopnia starzenia na papier izolacyjny. (Diagnostyka transformatorów z izolacją papierowo-olejową).

This article is focused about for analyse moisture of power oil transformer by proposed electroni... more This article is focused about for analyse moisture of power oil transformer by proposed electronic measuring system. Proposed system use time return voltage method (RVM). In the first sections of the paper is description of electronic proposal for measuring system. In the paper are presented connecting of power supply to the measurement system platform, power supply connecting of switching modules and connecting of high-voltage and rectifier part of the system. In the conclusion are the results which have mainly shows moisture content in distribution transformer.

2016 Diagnostic of Electrical Machines and Insulating Systems in Electrical Engineering (DEMISEE), 2016

Article presents theoretical and experimental analyses of possible effect of short-circuit forces... more Article presents theoretical and experimental analyses of possible effect of short-circuit forces on the transformer windings. The first part of the article is focused to the establishment and activity radial and axial forces during short circuit. It shows dimensions, direction and of course caused mechanical stress. Equation shows basic dependencies of these mechanical forces created in the transformer windings. Finally, the article presents experimental methods of diagnostics for analysis of the short-circuit forces on transformer windings.

2016 Conference on Diagnostics in Electrical Engineering (Diagnostika), 2016

Article presents analysis of insulating and mechanical state of transformers considering possible... more Article presents analysis of insulating and mechanical state of transformers considering possible effect of short-circuit currents on the winding. The first part of the article is focused to negative activity thermal and mechanical effects of short-circuit currents. The last part of the article is focused to the simulation method which shows the mechanical stress caused by the short circuit-currents. Finally, the article presents experimental frequency methods of diagnostics for analysis of the short-circuit effects on insulating and mechanical transformer state.

Measurement Science Review, 2018

The authors describe experimental and theoretical analyses of faults of power transformer winding... more The authors describe experimental and theoretical analyses of faults of power transformer winding. Faults were caused by mechanical effect of short-circuit currents. Measurements of transformer were carried out in high-voltage laboratory. Frequency and time diagnostic methods (method SFRA - Sweep Frequency Response Analysis, impact test) were used for the analyses. Coils of transformer windings were diagnosed by means of the SFRA method and the time impact test. The analyzed methods had a significant sensitivity to a relatively small deformation of coil. In the analysis a new technique for analyzing the effects of short-circuit currents is introduced. This technique is developed for high-voltage transformers (different types of power). The proposed analyses show that it is necessary to analyze the value of short-circuit current. Short-circuit current represents a danger for the operation of the power transformer. The proposed approach can be used for other types of transformers. Mor...

2015 56th International Scientific Conference on Power and Electrical Engineering of Riga Technical University (RTUCON), 2015

Article presents effects caused by electromagnetic forces on the transformer windings. It shows d... more Article presents effects caused by electromagnetic forces on the transformer windings. It shows dimensions, direction and of course caused mechanical stress. Equation shows basic dependencies of these mechanical forces created in the transformer windings. The last part of the article is focused to the simulation method which shows the mechanical stress caused by the short circuit-currents. This method is preferred for analysis of power transformer.

The article discusses the state of transformer insulation. For a more accurate determination of t... more The article discusses the state of transformer insulation. For a more accurate determination of the transformer insulation state are used three methods. The measurement of insulation resistance is the basic method and is set in the standard, value demonstrates the state of total insulation of transformer. Because the determination of moisture content of the paper insulation of transformer is very difficult process and it is necessary take a sample of paper, in this case is used method of return voltage. Return voltage measurement is more complex method and in many cases is determine a clear result very difficult. For evaluation of results have mainly impact moisture content and degree of aging of paper insulation and of course, content of conductive impurities in oil. Because the moisture content in oil is much lower than in the paper, return voltage measurement is used to determine the moisture content in paper insulation only. To confirm the results of return voltage measurement i...

The article discusses the state of transformer insulation. For a more accurate determination of t... more The article discusses the state of transformer insulation. For a more accurate determination of the transformer insulation state are used three methods. The measurement of insulation resistance is the basic method and is set in the standard, value demonstrates the state of total insulation of transformer. Because the determination of moisture content of the paper insulation of transformer is very difficult process and it is necessary take a sample of paper, in this case is used method of return voltage. Return voltage measurement is more complex method and in many cases is determine a clear result very difficult. For evaluation of results have mainly impact moisture content and degree of aging of paper insulation and of course, content of conductive impurities in oil. Because the moisture content in oil is much lower than in the paper, return voltage measurement is used to determine the moisture content in paper insulation only. To confirm the results of return voltage measurement i...

2018 International Conference on Diagnostics in Electrical Engineering (Diagnostika), 2018

This article is focused about for analyse moisture of power oil transformer by proposed electroni... more This article is focused about for analyse moisture of power oil transformer by proposed electronic measuring system. Proposed system use time return voltage method (RVM). In the first sections of the paper is description of electronic proposal for measuring system. In the paper are presented connecting of power supply to the measurement system platform, power supply connecting of switching modules and connecting of high-voltage and rectifier part of the system. In the conclusion are the results which have mainly shows moisture content in distribution transformer.

This article presents electromagnetic effects on transformer winding. It shows dimension of force... more This article presents electromagnetic effects on transformer winding. It shows dimension of force causing by short-circuits and how this force is created. In graphs are shown basics dependences for transformer and its dimension (its power) and mechanical forces. In the next is dealing with transient actions at overvoltages. There is showed how can overvoltages be created and how long overvoltages are take time. Third part of article is focused on measurement method. This method is preferred for testing big transformer. In method are described frequency ranges and possible exploitation of this method. Conclusion is proposal for next leading of this issue.

The article deals with method describing the state of transformer insulation. By the determining ... more The article deals with method describing the state of transformer insulation. By the determining its state is acquainted return voltage measurement and measurement the insulation resistance of windings. Return measurement voltage method is wide state specifying method which is not set in standards but in many cases is a method which is determining a clear and exact result. The results have mainly shows moisture content, content of conductive impurities in oil and degree of aging of paper insulation impact.

This article is focused about for electronic proposal measuring system of moisture analysis by re... more This article is focused about for electronic proposal measuring system of moisture analysis by return voltage method (RVM) for power oil transformers. RVM method is wide state specifying method which is not set in standards but in many cases is a method which is determining a clear and exact result. The results have mainly shows moisture content, content of conductive impurities in oil and degree of aging of paper insulation impact.

The first part of the paper deals with the base information about base measuring methods of trans... more The first part of the paper deals with the base information about base measuring methods of transformer insulating system. The second part of paper deals use of time methods - the method of return voltage measurement (RVM) and method of polarization depolarization current (PDC) for distribution transformer. These methods are used in the analysis of the insulating condition of power transformer with a system of oil-paper. In the other part, the paper presents experimental results of the moisture measurement for a real transformer 22/0.4 kV using time method RVM.