Pub Date : 2020-09-01DOI: 10.1109/Diagnostika49114.2020.9214766
O. Zidane, R. Haller, El-Sayed M. El-Refaie, M. K. Abd Elrahman
Partial discharge (PD) is one of the major factors that damage dielectric materials in medium and high voltage components. Therefore, partial discharge evaluation is generally used to observe the status of electrical insulation in high and medium voltage components used in the performance appreciation of an insulation system. In this work, partial discharge behavior on solid- air interfaces has been investigated commonly characterized as surface discharge. The investigation was performed by PD measurement as well as by adequate modelling for different insulating materials as the Natural Rubber (NR), Silicone Rubber (SiR), Ethylene Propylene Diene Monomer Rubber (EPDM) and High- Density Polyethylene (HDPE). Through modeling the partial discharge process, a better conception of the phenomenon may be achieved. The model of different homogeneous insulating materials has developed using Finite Element Analysis (COMSOL) software in parallel with MATLAB programming function. The results of the study indicate that the repetition rate and the peak apparent charge increased with the insulating material relative permittivity increase while the inception voltage does not change significantly.
{"title":"Partial Discharge Behavior on Solid- Air Interfaces at AC Stress Condition","authors":"O. Zidane, R. Haller, El-Sayed M. El-Refaie, M. K. Abd Elrahman","doi":"10.1109/Diagnostika49114.2020.9214766","DOIUrl":"https://doi.org/10.1109/Diagnostika49114.2020.9214766","url":null,"abstract":"Partial discharge (PD) is one of the major factors that damage dielectric materials in medium and high voltage components. Therefore, partial discharge evaluation is generally used to observe the status of electrical insulation in high and medium voltage components used in the performance appreciation of an insulation system. In this work, partial discharge behavior on solid- air interfaces has been investigated commonly characterized as surface discharge. The investigation was performed by PD measurement as well as by adequate modelling for different insulating materials as the Natural Rubber (NR), Silicone Rubber (SiR), Ethylene Propylene Diene Monomer Rubber (EPDM) and High- Density Polyethylene (HDPE). Through modeling the partial discharge process, a better conception of the phenomenon may be achieved. The model of different homogeneous insulating materials has developed using Finite Element Analysis (COMSOL) software in parallel with MATLAB programming function. The results of the study indicate that the repetition rate and the peak apparent charge increased with the insulating material relative permittivity increase while the inception voltage does not change significantly.","PeriodicalId":428555,"journal":{"name":"2020 International Conference on Diagnostics in Electrical Engineering (Diagnostika)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131045980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-01DOI: 10.1109/Diagnostika49114.2020.9214756
M. Boroš, A. Veľas, Filip Lenko
A microcontroller could be said to be a miniature computer whose components are integrated into a single case or package, they are often called single-chip microcomputers. These programmable microcontrollers are now part of almost all intelligent devices ranging from toys to medical devices to automotive control systems.Thanks to their simplicity and affordability, they have also found their place in the field of inventors, robot makers or early programmers. Thanks to their simplicity and possibilities they are also widely used among hobby enthusiasts using a raspberry or Arduino.In addition to the commercial and hobbies, programmable microcontrollers can also be used in scientific research. Thanks to their functionality, we have created several testing devices at the Faculty of Security Engineering, the University of Žilina, which can be used to assess the reliability of alarm systems or parts thereof. Among the most important are devices for testing alarm transmission systems, magnetic contacts, and passive infrared detectors. Thanks to these testing devices we have significantly automated the testing process, which is the basis for assessing the reliability of individual alarm systems. In the paper, we will point out the actual connection of testing devices based on programmable microcontrollers and testing possibilities to evaluate the reliability of alarm systems using experimental tests.
{"title":"Utilization of programmable microcontrollers to assess the reliability of alarm systems","authors":"M. Boroš, A. Veľas, Filip Lenko","doi":"10.1109/Diagnostika49114.2020.9214756","DOIUrl":"https://doi.org/10.1109/Diagnostika49114.2020.9214756","url":null,"abstract":"A microcontroller could be said to be a miniature computer whose components are integrated into a single case or package, they are often called single-chip microcomputers. These programmable microcontrollers are now part of almost all intelligent devices ranging from toys to medical devices to automotive control systems.Thanks to their simplicity and affordability, they have also found their place in the field of inventors, robot makers or early programmers. Thanks to their simplicity and possibilities they are also widely used among hobby enthusiasts using a raspberry or Arduino.In addition to the commercial and hobbies, programmable microcontrollers can also be used in scientific research. Thanks to their functionality, we have created several testing devices at the Faculty of Security Engineering, the University of Žilina, which can be used to assess the reliability of alarm systems or parts thereof. Among the most important are devices for testing alarm transmission systems, magnetic contacts, and passive infrared detectors. Thanks to these testing devices we have significantly automated the testing process, which is the basis for assessing the reliability of individual alarm systems. In the paper, we will point out the actual connection of testing devices based on programmable microcontrollers and testing possibilities to evaluate the reliability of alarm systems using experimental tests.","PeriodicalId":428555,"journal":{"name":"2020 International Conference on Diagnostics in Electrical Engineering (Diagnostika)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131736169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-01DOI: 10.1109/Diagnostika49114.2020.9214640
R. Procházka, O. Šefl
Electrical insulation materials, especially polymers, may contain miniature internal voids. Insulation systems created from such materials might hence suffer from the development of partial discharges in the voids. These discharges tend to erode the insulation material, which further increases their magnitude and quantity and leads to a significant enhancement of the degradation rate. Lately, due to the high number of power electronic components connected to the grid, repetitive high-frequency distortions occur in the parts of the network adjacent to these devices. Such distortions may cause the inception of partial discharge, which would usually not happen.This paper thus researches the effect of high-frequency voltage distortions on partial discharges in an artificially created internal void. Test samples containing the artificial voids were prepared by fused filament fabrication (FFF) method from PET-G material using a standard 3D printer. The employed FFF method of sample preparation achieved satisfactory precision in both the shape and size of the voids. The main observed parameters were oscillation waveform’s frequency and its phase shift relative to the supply voltage. PRPD patterns were gathered for a variety of different setups, and the influence of both parameters was evaluated.
{"title":"Influence of Voltage Distortion Shape on Partial Discharge Activity in Internal Voids","authors":"R. Procházka, O. Šefl","doi":"10.1109/Diagnostika49114.2020.9214640","DOIUrl":"https://doi.org/10.1109/Diagnostika49114.2020.9214640","url":null,"abstract":"Electrical insulation materials, especially polymers, may contain miniature internal voids. Insulation systems created from such materials might hence suffer from the development of partial discharges in the voids. These discharges tend to erode the insulation material, which further increases their magnitude and quantity and leads to a significant enhancement of the degradation rate. Lately, due to the high number of power electronic components connected to the grid, repetitive high-frequency distortions occur in the parts of the network adjacent to these devices. Such distortions may cause the inception of partial discharge, which would usually not happen.This paper thus researches the effect of high-frequency voltage distortions on partial discharges in an artificially created internal void. Test samples containing the artificial voids were prepared by fused filament fabrication (FFF) method from PET-G material using a standard 3D printer. The employed FFF method of sample preparation achieved satisfactory precision in both the shape and size of the voids. The main observed parameters were oscillation waveform’s frequency and its phase shift relative to the supply voltage. PRPD patterns were gathered for a variety of different setups, and the influence of both parameters was evaluated.","PeriodicalId":428555,"journal":{"name":"2020 International Conference on Diagnostics in Electrical Engineering (Diagnostika)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120959326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-01DOI: 10.1109/Diagnostika49114.2020.9214713
O. Šefl, P. Veselý, Jaroslav Minář, K. Dušek
The degradation of plastic materials induced by solar radiation can limit their use in outdoor applications. Therefore, we aimed to find a relationship between the photodegradation of 3D printed polylactic acid (PLA) and its electrical and thermomechanical properties. In the first stage, the printing settings were optimized with regard to the dielectric strength of samples. Afterward, the sets of printed specimens were exposed to UV light of different spectrum and duration. UV gas-discharge lamps with spectral peaks at 254 and 385 nm were used as intense UV light sources; the individual exposure times were chosen as 6, 12, 24, 48, and 96 hours. Subsequently, the dielectric strength of each set was evaluated, and thermomechanical analyses were performed. Although the irradiation at 254 nm caused substantial degradation of PLA, it did not remarkably affect its dielectric strength. Nonetheless, both sources of UV light caused a considerable brittleness that might be the limiting factor for the outdoor application of PLA.
{"title":"Novel Electrical Insulation Materials – Photodegradation Endurance of 3D Printed Polylactic Acid","authors":"O. Šefl, P. Veselý, Jaroslav Minář, K. Dušek","doi":"10.1109/Diagnostika49114.2020.9214713","DOIUrl":"https://doi.org/10.1109/Diagnostika49114.2020.9214713","url":null,"abstract":"The degradation of plastic materials induced by solar radiation can limit their use in outdoor applications. Therefore, we aimed to find a relationship between the photodegradation of 3D printed polylactic acid (PLA) and its electrical and thermomechanical properties. In the first stage, the printing settings were optimized with regard to the dielectric strength of samples. Afterward, the sets of printed specimens were exposed to UV light of different spectrum and duration. UV gas-discharge lamps with spectral peaks at 254 and 385 nm were used as intense UV light sources; the individual exposure times were chosen as 6, 12, 24, 48, and 96 hours. Subsequently, the dielectric strength of each set was evaluated, and thermomechanical analyses were performed. Although the irradiation at 254 nm caused substantial degradation of PLA, it did not remarkably affect its dielectric strength. Nonetheless, both sources of UV light caused a considerable brittleness that might be the limiting factor for the outdoor application of PLA.","PeriodicalId":428555,"journal":{"name":"2020 International Conference on Diagnostics in Electrical Engineering (Diagnostika)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120985062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-01DOI: 10.1109/Diagnostika49114.2020.9214610
Jan Leffler, Ondřej Rauner, P. Trnka
The current trend in the field of industrial diagnostics of the electrical appliances is to lower the maintenance costs by appropriate procedures of optimization of all processes from design, manufacturing, operation to decommissioning and recycling. Online monitoring of the current state of the monitored object and its gradual deterioration are becoming an important issue. Nowadays this topic is also very important in the concept of Industry 4.0 because the importance is given to asset management, which helps organizations to manage their assets. This could only be done by using a properly designed diagnostic system. This paper is dealing with the comparison of two different concepts of design and realization of an online diagnostic system, which creates the core of Condition Based Management approach.
{"title":"Comparison of two different approaches to the design of an online diagnostic system","authors":"Jan Leffler, Ondřej Rauner, P. Trnka","doi":"10.1109/Diagnostika49114.2020.9214610","DOIUrl":"https://doi.org/10.1109/Diagnostika49114.2020.9214610","url":null,"abstract":"The current trend in the field of industrial diagnostics of the electrical appliances is to lower the maintenance costs by appropriate procedures of optimization of all processes from design, manufacturing, operation to decommissioning and recycling. Online monitoring of the current state of the monitored object and its gradual deterioration are becoming an important issue. Nowadays this topic is also very important in the concept of Industry 4.0 because the importance is given to asset management, which helps organizations to manage their assets. This could only be done by using a properly designed diagnostic system. This paper is dealing with the comparison of two different concepts of design and realization of an online diagnostic system, which creates the core of Condition Based Management approach.","PeriodicalId":428555,"journal":{"name":"2020 International Conference on Diagnostics in Electrical Engineering (Diagnostika)","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131712577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-01DOI: 10.1109/Diagnostika49114.2020.9214742
M. Šebok, Milan Šimko, M. Chupáč, M. Gutten, Viktor Cefer
The paper is focused on analyses of online diagnostics with analysis of induction motor, transformer and AC generator by means of thermovision measurement. In the 1-st part of article is performed theoretical analysis of thermovision measurement on the base infrared thermal radiation. In the 2-nd part of article is performed experimental diagnostics and analysis by thermovision camera on induction motor, high-voltage transformer and AC generator. In the end are performed conclusions according to measured values by the means of thermovision analysis.
{"title":"Prophylactic Diagnostics for Electrical Machines","authors":"M. Šebok, Milan Šimko, M. Chupáč, M. Gutten, Viktor Cefer","doi":"10.1109/Diagnostika49114.2020.9214742","DOIUrl":"https://doi.org/10.1109/Diagnostika49114.2020.9214742","url":null,"abstract":"The paper is focused on analyses of online diagnostics with analysis of induction motor, transformer and AC generator by means of thermovision measurement. In the 1-st part of article is performed theoretical analysis of thermovision measurement on the base infrared thermal radiation. In the 2-nd part of article is performed experimental diagnostics and analysis by thermovision camera on induction motor, high-voltage transformer and AC generator. In the end are performed conclusions according to measured values by the means of thermovision analysis.","PeriodicalId":428555,"journal":{"name":"2020 International Conference on Diagnostics in Electrical Engineering (Diagnostika)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132065375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-01DOI: 10.1109/Diagnostika49114.2020.9214775
P. Pečínka, V. Pečínková, S. Kocman, Stanislav Rusnok, P. Kačor
The paper deals with the material properties of metal sheets, which are used for construction of electric rotating machines, especially induction machines. A total of four samples of M330-50A sheets from two different manufacturers were selected. Two samples of sheets were cutting in the longitudinal direction of rolling and two samples of sheets cutting in the transverse direction. This combination of metal sheets was use for the study. The samples were metallographically prepared by sanding, polishing and etching. Metallographic sections were observed on an optical microscope. The approximate chemical composition of each sample was determined by scanning electron microscope (SEM). The electromagnetic behavior of samples, were determined with using measurement of BH characteristics by Epstein frame. Measurement of BH characteristics for both manufacturers was performed in the accordance with relevant standards (CEI IEC 404-2). The results of the investigation were further evaluated and compared. In the last part there is an enumeration of the possibility of influencing electrical properties in dependence on material composition of electrical steels and evaluation of own investigation.
{"title":"Analysis of material properties metal sheets for the construction of induction motor","authors":"P. Pečínka, V. Pečínková, S. Kocman, Stanislav Rusnok, P. Kačor","doi":"10.1109/Diagnostika49114.2020.9214775","DOIUrl":"https://doi.org/10.1109/Diagnostika49114.2020.9214775","url":null,"abstract":"The paper deals with the material properties of metal sheets, which are used for construction of electric rotating machines, especially induction machines. A total of four samples of M330-50A sheets from two different manufacturers were selected. Two samples of sheets were cutting in the longitudinal direction of rolling and two samples of sheets cutting in the transverse direction. This combination of metal sheets was use for the study. The samples were metallographically prepared by sanding, polishing and etching. Metallographic sections were observed on an optical microscope. The approximate chemical composition of each sample was determined by scanning electron microscope (SEM). The electromagnetic behavior of samples, were determined with using measurement of BH characteristics by Epstein frame. Measurement of BH characteristics for both manufacturers was performed in the accordance with relevant standards (CEI IEC 404-2). The results of the investigation were further evaluated and compared. In the last part there is an enumeration of the possibility of influencing electrical properties in dependence on material composition of electrical steels and evaluation of own investigation.","PeriodicalId":428555,"journal":{"name":"2020 International Conference on Diagnostics in Electrical Engineering (Diagnostika)","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126563938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-01DOI: 10.1109/Diagnostika49114.2020.9214599
O. Michal, V. Mentlík
Recent demands for thin and more resistant materials, that can be used in rotating machines, is causing the evolution of the new generations of materials. Conventional electro-insulating materials include a variety of composite materials, such as the combination of resin, mica and glass fiber cloths. Unfortunately, for effective usage of most composite materials, the thick layer must be used. This affects the space charge accumulation and also thermal conductivity. One of the means to partially eliminate this problem is to reduce the thickness of the entire insulating system. On the other hand, reducing the thickness comes with the reduction of electrical durability. In recent years, the nanocomponents are gaining popularity in various applications. This article presents the experiment of using a combination of commonly used epoxy resin and novel types of non-woven polymer nanofiber materials and modified silicon dioxide nanoparticles. In this experiment, the emphasis was given to the influence concerning the area density of the nanofibers on the electrical parameters of the composite specimen. Based on the results, the influence of the area density has been found. Also, the lower values of the area density have a slightly higher positive effect on the electrical parameters.
{"title":"Area density of Polyimide Nanofibers and its Influence on the Properties of Epoxy Based Nanodielectrics","authors":"O. Michal, V. Mentlík","doi":"10.1109/Diagnostika49114.2020.9214599","DOIUrl":"https://doi.org/10.1109/Diagnostika49114.2020.9214599","url":null,"abstract":"Recent demands for thin and more resistant materials, that can be used in rotating machines, is causing the evolution of the new generations of materials. Conventional electro-insulating materials include a variety of composite materials, such as the combination of resin, mica and glass fiber cloths. Unfortunately, for effective usage of most composite materials, the thick layer must be used. This affects the space charge accumulation and also thermal conductivity. One of the means to partially eliminate this problem is to reduce the thickness of the entire insulating system. On the other hand, reducing the thickness comes with the reduction of electrical durability. In recent years, the nanocomponents are gaining popularity in various applications. This article presents the experiment of using a combination of commonly used epoxy resin and novel types of non-woven polymer nanofiber materials and modified silicon dioxide nanoparticles. In this experiment, the emphasis was given to the influence concerning the area density of the nanofibers on the electrical parameters of the composite specimen. Based on the results, the influence of the area density has been found. Also, the lower values of the area density have a slightly higher positive effect on the electrical parameters.","PeriodicalId":428555,"journal":{"name":"2020 International Conference on Diagnostics in Electrical Engineering (Diagnostika)","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122275002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-26DOI: 10.1109/Diagnostika49114.2020.9214647
S. Uhrig, F. Öttl, R. Hinterholzer, N. Augeneder
The frequency response analysis (FRA) is a known highly sensitive method to detect mechanical and electrical defects in power transformers. Investigations already showed, that this technique is applicable to detect broken windings or shorted turns in rotor and stator of rotating machines. Here, the applicability of FRA to other defects was investigated, like broken rods of damping windings in synchronous machines or in a squirrel cage of induction motors, which often can be detected only by disassembling the machine. The reason lies in the design: damping windings as well as the squirrel cages have no accessible outer terminal, which can be used for electrical measurements. As the FRA method is capable to measure also capacitive or inductive couplings, it might be a possible low effort alternative. This investigation focuses on the reliability of failure detection. For a clear conclusion, numerous tests were performed on rotating machines of different types. It was found, that the frequency response can be measured on assembled rotating machines highly reproducible up to 1 MHz in different setups. Main factors to be considered are a good connection technique and a clear description of the measurement setup for later tests. A comparative analysis is only possible for the same phase configuration as well as the same rotation angle of the rotor. Like power transformers a time-based comparison is preferred. Different phases have not exactly the same frequency responses. For the investigation, described in this contribution, broken rods in a squirrel cage of a 55 kVA induction motor and in the damping winding of a 37 kVA synchronous machine were re-produced. It was found, that the FRA method is sensitive enough to identify even single defects.
{"title":"Reliable Diagnostics on Rotating Machines using FRA","authors":"S. Uhrig, F. Öttl, R. Hinterholzer, N. Augeneder","doi":"10.1109/Diagnostika49114.2020.9214647","DOIUrl":"https://doi.org/10.1109/Diagnostika49114.2020.9214647","url":null,"abstract":"The frequency response analysis (FRA) is a known highly sensitive method to detect mechanical and electrical defects in power transformers. Investigations already showed, that this technique is applicable to detect broken windings or shorted turns in rotor and stator of rotating machines. Here, the applicability of FRA to other defects was investigated, like broken rods of damping windings in synchronous machines or in a squirrel cage of induction motors, which often can be detected only by disassembling the machine. The reason lies in the design: damping windings as well as the squirrel cages have no accessible outer terminal, which can be used for electrical measurements. As the FRA method is capable to measure also capacitive or inductive couplings, it might be a possible low effort alternative. This investigation focuses on the reliability of failure detection. For a clear conclusion, numerous tests were performed on rotating machines of different types. It was found, that the frequency response can be measured on assembled rotating machines highly reproducible up to 1 MHz in different setups. Main factors to be considered are a good connection technique and a clear description of the measurement setup for later tests. A comparative analysis is only possible for the same phase configuration as well as the same rotation angle of the rotor. Like power transformers a time-based comparison is preferred. Different phases have not exactly the same frequency responses. For the investigation, described in this contribution, broken rods in a squirrel cage of a 55 kVA induction motor and in the damping winding of a 37 kVA synchronous machine were re-produced. It was found, that the FRA method is sensitive enough to identify even single defects.","PeriodicalId":428555,"journal":{"name":"2020 International Conference on Diagnostics in Electrical Engineering (Diagnostika)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127309039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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