Pub Date : 2021-12-09DOI: 10.20998/2079-3944.2021.2.02
V. Lytvynenko, A. Sereda, I. Varshamova, Olena Korol
Circuit breakers for overcurrent protection of semiconductor converters limit the duration and amplitude of the overcurrent at such a level that its thermal effect does not exceed the maximum allowable thermal protection index of the protected semiconductor device. The limitation of the thermal action of the short-circuit current is achieved by reducing the operation time of the circuit breaker. The design of the circuit breaker is changed in such a way that instead of the basic electromagnetic release is used an induction-dynamic release, which consists of an inductor with a ferromagnetic core and a rotary armature in the form of a copper disk. The electrodynamic force producing by the induction-dynamic release for quick operation is determined by the coefficient of mutual inductance of the inductor coil and the armature. Using of a ferromagnetic core entailed an increase in the coefficient of mutual inductance of the coil and armature, therefore, an increase in the electrodynamic force producing by the release, and a decrease in own tripping time of the circuit breaker. On a prototype, an experimental study of the proper operation time of the release was carried out at various values of the electrical parameters of the capacitor bank of the inductor power supply, the winding parameters of the inductor coil and the disk dimensions. The research results have proved both a decrease in the tripping time of the circuit breaker while conserving the energy of the capacitor bank of the inductor, and a decrease in the required energy of the capacitor bank to power the inductor while maintaining the minimum tripping time of the circuit breaker. Reducing the energy of the capacitor bank of the inductor made it possible to reduce the capacity and voltage of the capacitor bank of the supply of the release, and, consequently, its dimensions.
{"title":"Experimental research of the influence of a ferromagnetic core on the speed of an induction-dynamic release with turning anchor type","authors":"V. Lytvynenko, A. Sereda, I. Varshamova, Olena Korol","doi":"10.20998/2079-3944.2021.2.02","DOIUrl":"https://doi.org/10.20998/2079-3944.2021.2.02","url":null,"abstract":"Circuit breakers for overcurrent protection of semiconductor converters limit the duration and amplitude of the overcurrent at such a level that its thermal effect does not exceed the maximum allowable thermal protection index of the protected semiconductor device. The limitation of the thermal action of the short-circuit current is achieved by reducing the operation time of the circuit breaker. The design of the circuit breaker is changed in such a way that instead of the basic electromagnetic release is used an induction-dynamic release, which consists of an inductor with a ferromagnetic core and a rotary armature in the form of a copper disk. The electrodynamic force producing by the induction-dynamic release for quick operation is determined by the coefficient of mutual inductance of the inductor coil and the armature. Using of a ferromagnetic core entailed an increase in the coefficient of mutual inductance of the coil and armature, therefore, an increase in the electrodynamic force producing by the release, and a decrease in own tripping time of the circuit breaker. On a prototype, an experimental study of the proper operation time of the release was carried out at various values of the electrical parameters of the capacitor bank of the inductor power supply, the winding parameters of the inductor coil and the disk dimensions. The research results have proved both a decrease in the tripping time of the circuit breaker while conserving the energy of the capacitor bank of the inductor, and a decrease in the required energy of the capacitor bank to power the inductor while maintaining the minimum tripping time of the circuit breaker. Reducing the energy of the capacitor bank of the inductor made it possible to reduce the capacity and voltage of the capacitor bank of the supply of the release, and, consequently, its dimensions.","PeriodicalId":385206,"journal":{"name":"Bulletin of NTU \"KhPI\". Series: Problems of Electrical Machines and Apparatus Perfection. The Theory and Practice","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129533708","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 : 2021-12-09DOI: 10.20998/2079-3944.2021.2.11
P. Andrienko, V. Vasilevskij, Ivan Vittsivskyi
Fused Deposition Modeling is an additive manufacturing technology where a temperature-controlled head extrudes a thermoplastic material onto a build platform in a predetermined path. Standard, advanced thermoplastics and composites are used for printing. Among the areas of application for FDM printing, the main ones are rapid prototyping, as well as small-scale and batch production. The purpose of the work is the implementation of FDM 3D printing technology in the educational process of students in specialty 141 "Electroenergy, electrotechnics and electromechanics". The features of the technology of additive manufacturing of electrical apparatuses parts by the method of FDM printing have been investigated. Parts of four standard sizes were printed using ABS + and PLA plastics, namely, current transformer carcasses in the amount of 110 pieces and sensor bodies in the amount of 100 pieces. For printing, an FDM 3D printer was used built on the XZ Head Y Bed kinematic scheme with an open working chamber. The analysis of defects in finished products was carried out, which showed that the main defects are deviations of the actual dimensions and geometric shape of the finished products. Ways to prevent the occurrence of these defects are considered, namely, correcting the size of the model at the stage of preparing the model for printing, minimizing the filling density of the model, using brims in models, setting the optimal temperature of the working platform and simultaneously printing several products. The results of the study o features of the technology of additive manufacturing of electrical apparatuses parts by the method of FDM printing made it possible to develop a set of laboratory works for students of the specialty 141 "Electroenergy, electrotechnics and electromechanics".
{"title":"Experience of implementation in educational process modern technologies of FDM 3D printing","authors":"P. Andrienko, V. Vasilevskij, Ivan Vittsivskyi","doi":"10.20998/2079-3944.2021.2.11","DOIUrl":"https://doi.org/10.20998/2079-3944.2021.2.11","url":null,"abstract":"Fused Deposition Modeling is an additive manufacturing technology where a temperature-controlled head extrudes a thermoplastic material onto a build platform in a predetermined path. Standard, advanced thermoplastics and composites are used for printing. Among the areas of application for FDM printing, the main ones are rapid prototyping, as well as small-scale and batch production. The purpose of the work is the implementation of FDM 3D printing technology in the educational process of students in specialty 141 \"Electroenergy, electrotechnics and electromechanics\". The features of the technology of additive manufacturing of electrical apparatuses parts by the method of FDM printing have been investigated. Parts of four standard sizes were printed using ABS + and PLA plastics, namely, current transformer carcasses in the amount of 110 pieces and sensor bodies in the amount of 100 pieces. For printing, an FDM 3D printer was used built on the XZ Head Y Bed kinematic scheme with an open working chamber. The analysis of defects in finished products was carried out, which showed that the main defects are deviations of the actual dimensions and geometric shape of the finished products. Ways to prevent the occurrence of these defects are considered, namely, correcting the size of the model at the stage of preparing the model for printing, minimizing the filling density of the model, using brims in models, setting the optimal temperature of the working platform and simultaneously printing several products. The results of the study o features of the technology of additive manufacturing of electrical apparatuses parts by the method of FDM printing made it possible to develop a set of laboratory works for students of the specialty 141 \"Electroenergy, electrotechnics and electromechanics\".","PeriodicalId":385206,"journal":{"name":"Bulletin of NTU \"KhPI\". Series: Problems of Electrical Machines and Apparatus Perfection. The Theory and Practice","volume":"22 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121004063","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 : 2021-12-09DOI: 10.20998/2079-3944.2021.2.12
Ye. Honcharov, Nataliya Kriukova, V. Markov, I. Polyakov
The article deals with the actual problems of using the energy released by the human body. The question arises how much energy can the human body generate? Is it possible to use this energy for domestic and industrial needs? In the 18th and 19th centuries, the first scientific works on this topic appeared. It turned out that the charge carriers in the proteins of a living organism are protons and electrons, which, together with the electron-hole conduction system, create a single conductivity inherent only in a living organism. The electrical activity of the brain is assessed by voltage pulses with an amplitude of 500 μV of various frequencies from 0.5 to 55 Hz. It is impossible to receive pulses with such a frequency and such an amplitude from only ionic-type charge carriers. Electrochemical current sources are inertial; therefore, this fact can be direct evidence of the presence of electronic movement of charge carriers in the brain and the nervous system as a whole. It is quite realistic to use the thermal energy of the human body. Currently, the central building of the Stockholm railway station has been turned into a kind of experimental testing ground. Every day about 250 thousand people pass through the station building, who emit up to 25 MW of thermal energy. Most of it in the form of heated air is collected in ventilation and through heat exchangers energy is transferred to heat water in the heating system of another building. According to rough estimates, the efficiency of such a system can save up to 25% of the energy spent on heating the building. Inside a person, electric currents of various frequencies are generated in 7 biological power plants: in the heart, in the brain and in the five sense organs. All the electricity that is generated inside the human body is absorbed by its own tissues. Not a single electron produced inside a living organism leaves the human body, and does not pass into the environment, but is absorbed by the skin. This is the reason for the closure of the human electrical system. The body itself absorbs all the electricity that it previously produced. The energy generated by the human body is divided into mechanical, thermal, and electrical. The thermal energy of the human body can be used most effectively. Mechanical energy can also be used, but with much less efficiency. The electrical energy of the human body at this stage in the development of science and technology is practically impossible to use. Its use is likely to become real in the very distant future
{"title":"A human body as an energy source","authors":"Ye. Honcharov, Nataliya Kriukova, V. Markov, I. Polyakov","doi":"10.20998/2079-3944.2021.2.12","DOIUrl":"https://doi.org/10.20998/2079-3944.2021.2.12","url":null,"abstract":"The article deals with the actual problems of using the energy released by the human body. The question arises how much energy can the human body generate? Is it possible to use this energy for domestic and industrial needs? In the 18th and 19th centuries, the first scientific works on this topic appeared. It turned out that the charge carriers in the proteins of a living organism are protons and electrons, which, together with the electron-hole conduction system, create a single conductivity inherent only in a living organism. The electrical activity of the brain is assessed by voltage pulses with an amplitude of 500 μV of various frequencies from 0.5 to 55 Hz. It is impossible to receive pulses with such a frequency and such an amplitude from only ionic-type charge carriers. Electrochemical current sources are inertial; therefore, this fact can be direct evidence of the presence of electronic movement of charge carriers in the brain and the nervous system as a whole. It is quite realistic to use the thermal energy of the human body. Currently, the central building of the Stockholm railway station has been turned into a kind of experimental testing ground. Every day about 250 thousand people pass through the station building, who emit up to 25 MW of thermal energy. Most of it in the form of heated air is collected in ventilation and through heat exchangers energy is transferred to heat water in the heating system of another building. According to rough estimates, the efficiency of such a system can save up to 25% of the energy spent on heating the building. Inside a person, electric currents of various frequencies are generated in 7 biological power plants: in the heart, in the brain and in the five sense organs. All the electricity that is generated inside the human body is absorbed by its own tissues. Not a single electron produced inside a living organism leaves the human body, and does not pass into the environment, but is absorbed by the skin. This is the reason for the closure of the human electrical system. The body itself absorbs all the electricity that it previously produced. The energy generated by the human body is divided into mechanical, thermal, and electrical. The thermal energy of the human body can be used most effectively. Mechanical energy can also be used, but with much less efficiency. The electrical energy of the human body at this stage in the development of science and technology is practically impossible to use. Its use is likely to become real in the very distant future","PeriodicalId":385206,"journal":{"name":"Bulletin of NTU \"KhPI\". Series: Problems of Electrical Machines and Apparatus Perfection. The Theory and Practice","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116830639","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 : 2021-12-09DOI: 10.20998/2079-3944.2021.2.06
V. Zolotarev, O. Golik, Eugene Moskvitin, Mykola Zykоv, A. Shurupova, L. Shchebeniuk, Oksana Vasylieva
With the introduction into highly filled halogen-free plastics production, the mechanical strength of which in operation directly depends on the flame retardant content and application technology, it becomes important to control the cable sheath mechanical characteristics in a fireproof design. Polymeric materials and their compositions are viscoelastic materials for which the mechanical properties depend on the stress time. The results of estimating the deformation samples rate elongation from the uniaxial stretching time at different dilution rates of the clamps in the mechanical characteristics determining process for halogen-free cable plastics in regulatory tests under production conditions are presented. It is shown that the inner and outer layers of the halogen-free plastic cable sheath have significantly different values of the plasticity normative parameter: differences evidence in the polymer structure in the inner and outer layers of the sheath due to the forced deformation process during extrusion, which is forced polymer structure orientation. Elongation relative deformation experimental dependences δL(t) of the samples on the uniaxial stretching time at different clamps dilution speeds are given, which illustrate confirmed by a large data array the dependencies shape reproducibility δL(t) for different in structure similar filled halogen-free polymers. The strain rate dependence model on tensile time as the sum of instantaneous-elastic, viscoelastic and instantaneous-plastic (irreversible) is proposed: dε/dt = λпр exp ( – t/λпр) + {∫ λ1 exp(–τ/λ1).exp[–(t–τ)/λ2]dτ]}/Δt. The appropriate parameter estimates of the named samples deformation components obtained by approximating the experimental data by the proposed model are given. The proposed model, firstly, explains the presence characteristic relative deformation maximum (t = tm) as a two interdependent deformation processes superposition with different aftermath λ. Secondly, it allows to specify the requirements for testing: with increasing the clamps dilution speed, the maximum time tm decreases significantly, respectively, the higher the clamps dilution speed, the smaller interval time Δt between a successive sample control section length measurements. This conclusion was experimentally confirmed for a specific material at a speed of 250 mm/min
{"title":"Model of deformation growth dynamics during filled polymer materials mechanical tests under cable production conditions","authors":"V. Zolotarev, O. Golik, Eugene Moskvitin, Mykola Zykоv, A. Shurupova, L. Shchebeniuk, Oksana Vasylieva","doi":"10.20998/2079-3944.2021.2.06","DOIUrl":"https://doi.org/10.20998/2079-3944.2021.2.06","url":null,"abstract":"With the introduction into highly filled halogen-free plastics production, the mechanical strength of which in operation directly depends on the flame retardant content and application technology, it becomes important to control the cable sheath mechanical characteristics in a fireproof design. Polymeric materials and their compositions are viscoelastic materials for which the mechanical properties depend on the stress time. The results of estimating the deformation samples rate elongation from the uniaxial stretching time at different dilution rates of the clamps in the mechanical characteristics determining process for halogen-free cable plastics in regulatory tests under production conditions are presented. It is shown that the inner and outer layers of the halogen-free plastic cable sheath have significantly different values of the plasticity normative parameter: differences evidence in the polymer structure in the inner and outer layers of the sheath due to the forced deformation process during extrusion, which is forced polymer structure orientation. Elongation relative deformation experimental dependences δL(t) of the samples on the uniaxial stretching time at different clamps dilution speeds are given, which illustrate confirmed by a large data array the dependencies shape reproducibility δL(t) for different in structure similar filled halogen-free polymers. The strain rate dependence model on tensile time as the sum of instantaneous-elastic, viscoelastic and instantaneous-plastic (irreversible) is proposed: dε/dt = λпр exp ( – t/λпр) + {∫ λ1 exp(–τ/λ1).exp[–(t–τ)/λ2]dτ]}/Δt. The appropriate parameter estimates of the named samples deformation components obtained by approximating the experimental data by the proposed model are given. The proposed model, firstly, explains the presence characteristic relative deformation maximum (t = tm) as a two interdependent deformation processes superposition with different aftermath λ. Secondly, it allows to specify the requirements for testing: with increasing the clamps dilution speed, the maximum time tm decreases significantly, respectively, the higher the clamps dilution speed, the smaller interval time Δt between a successive sample control section length measurements. This conclusion was experimentally confirmed for a specific material at a speed of 250 mm/min","PeriodicalId":385206,"journal":{"name":"Bulletin of NTU \"KhPI\". Series: Problems of Electrical Machines and Apparatus Perfection. The Theory and Practice","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133579442","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 : 2021-12-09DOI: 10.20998/2079-3944.2021.2.08
Enkyeom Kim, I. Korostelev
An alternative method for field MOV surge arresters diagnosing was observed, the controlled characteristic was the surge voltage of a gap arrester. The condenser that was connected in series with gap arrester was applied as voltage measurement sensor. Electrical aging of active elements (MOV), surge arrester insulation degradation and other types of electric faults causes to voltage increase at capacitor. The voltage value can be measured directly or the energy stored in capacitor can be transformed to electromagnetic signal and, then, registered remotely by specific radio transceiver. The capacitor connected in series with the surge arrester can also be used for leakage current limitation during all the life period of surge arrester. Shunted with a spark gap and presented as the low-current gap arrester with pre-sated discharge voltage glass (porcelain) pin-cap insulator can be the simplest, but reliable sensor. Taking into consideration modern technologies the surge arrester statement continuous monitoring system can be designed. It also allows locating the place of damaged arrester that is particularly true for remote maintenance of equipped with surge protection devices electrical
{"title":"Voltage characteristic as a parameter for surge arrester diagnosing","authors":"Enkyeom Kim, I. Korostelev","doi":"10.20998/2079-3944.2021.2.08","DOIUrl":"https://doi.org/10.20998/2079-3944.2021.2.08","url":null,"abstract":"An alternative method for field MOV surge arresters diagnosing was observed, the controlled characteristic was the surge voltage of a gap arrester. The condenser that was connected in series with gap arrester was applied as voltage measurement sensor. Electrical aging of active elements (MOV), surge arrester insulation degradation and other types of electric faults causes to voltage increase at capacitor. The voltage value can be measured directly or the energy stored in capacitor can be transformed to electromagnetic signal and, then, registered remotely by specific radio transceiver. The capacitor connected in series with the surge arrester can also be used for leakage current limitation during all the life period of surge arrester. Shunted with a spark gap and presented as the low-current gap arrester with pre-sated discharge voltage glass (porcelain) pin-cap insulator can be the simplest, but reliable sensor. Taking into consideration modern technologies the surge arrester statement continuous monitoring system can be designed. It also allows locating the place of damaged arrester that is particularly true for remote maintenance of equipped with surge protection devices electrical","PeriodicalId":385206,"journal":{"name":"Bulletin of NTU \"KhPI\". Series: Problems of Electrical Machines and Apparatus Perfection. The Theory and Practice","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127948417","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 : 2021-12-09DOI: 10.20998/2079-3944.2021.2.10
R. Mokhnach
The article describes the technology of manufacturing conductors for power supply systems for cranes, railway vehicles, powerful critical electric motors and power systems. The results of studies for copper-steel samples are shown; in these systems there is a decrease in material losses due to an increase in the strength and durability of products. The proposed technology can be used to use steel-copper wires in power supply loss compensation systems.
{"title":"Improvement of technology of production of compensation copper and copper steel current ducts","authors":"R. Mokhnach","doi":"10.20998/2079-3944.2021.2.10","DOIUrl":"https://doi.org/10.20998/2079-3944.2021.2.10","url":null,"abstract":"The article describes the technology of manufacturing conductors for power supply systems for cranes, railway vehicles, powerful critical electric motors and power systems. The results of studies for copper-steel samples are shown; in these systems there is a decrease in material losses due to an increase in the strength and durability of products. The proposed technology can be used to use steel-copper wires in power supply loss compensation systems.","PeriodicalId":385206,"journal":{"name":"Bulletin of NTU \"KhPI\". Series: Problems of Electrical Machines and Apparatus Perfection. The Theory and Practice","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128952850","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 : 2021-12-09DOI: 10.20998/2079-3944.2021.2.04
Yuriy Vaskovskiy, A. Geraskin, K. Tatarinov
The physical processes in the damper system of the rotor with the appearance of a static eccentricity of the rotor for two types of salient-pole synchronous machines - a capsule hydrogenator SGK 538/160-70M with a capacity of 22 MW and a synchronous generator with a capacity of 500 kW were investigated by means of mathematical modeling. A field mathematical model has been developed that takes into account the combined action of three physical fields of different nature: electromagnetic, temperature and field of thermomechanical stresses, and makes it possible to evaluate the heating and three-dimensional distribution of thermomechanical stresses in the structural elements of the rotor damper system of a salient-pole synchronous machine. These physical processes cause gradual destruction of the structure of the rotor damper system. It is proved that the primary cause of degradation and damage of the damping system of the rotor of an open-pole synchronous machine is the uneven distribution of induced currents in the rods at the poles of the rotor, which occurs when the machine works asynchronously or with the appearance of rotor static eccentricity. The largest induced currents and heat occur in the rods located at the edges of the pole pieces, while the central rods at the pole are heated significantly less. This asymmetric heating of the damping system of the rotor leads to significant thermomechanical stresses in the elements of the damping system of the rotor, which significantly depend on the magnitude of the eccentricity and slippery of the rotor in asynchronous mode. The magnitude of the total thermomechanical stresses in the rods is influenced not only by axially directed forces but also by transverse forces in the end short-circuiting elements. At considerable slippery and eccentricities there are inadmissibly big breaking forces which break cores and face short-circuiting elements of a damping system of a rotor. According to the results of the analysis, the heating and thermomechanical stresses of the structural elements were determined and recommendations for its structural improvement were given.
{"title":"Research of dampher system damage physical processes of synchronous machines rotor","authors":"Yuriy Vaskovskiy, A. Geraskin, K. Tatarinov","doi":"10.20998/2079-3944.2021.2.04","DOIUrl":"https://doi.org/10.20998/2079-3944.2021.2.04","url":null,"abstract":"The physical processes in the damper system of the rotor with the appearance of a static eccentricity of the rotor for two types of salient-pole synchronous machines - a capsule hydrogenator SGK 538/160-70M with a capacity of 22 MW and a synchronous generator with a capacity of 500 kW were investigated by means of mathematical modeling. A field mathematical model has been developed that takes into account the combined action of three physical fields of different nature: electromagnetic, temperature and field of thermomechanical stresses, and makes it possible to evaluate the heating and three-dimensional distribution of thermomechanical stresses in the structural elements of the rotor damper system of a salient-pole synchronous machine. These physical processes cause gradual destruction of the structure of the rotor damper system. It is proved that the primary cause of degradation and damage of the damping system of the rotor of an open-pole synchronous machine is the uneven distribution of induced currents in the rods at the poles of the rotor, which occurs when the machine works asynchronously or with the appearance of rotor static eccentricity. The largest induced currents and heat occur in the rods located at the edges of the pole pieces, while the central rods at the pole are heated significantly less. This asymmetric heating of the damping system of the rotor leads to significant thermomechanical stresses in the elements of the damping system of the rotor, which significantly depend on the magnitude of the eccentricity and slippery of the rotor in asynchronous mode. The magnitude of the total thermomechanical stresses in the rods is influenced not only by axially directed forces but also by transverse forces in the end short-circuiting elements. At considerable slippery and eccentricities there are inadmissibly big breaking forces which break cores and face short-circuiting elements of a damping system of a rotor. According to the results of the analysis, the heating and thermomechanical stresses of the structural elements were determined and recommendations for its structural improvement were given.","PeriodicalId":385206,"journal":{"name":"Bulletin of NTU \"KhPI\". Series: Problems of Electrical Machines and Apparatus Perfection. The Theory and Practice","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125975396","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 : 2021-12-09DOI: 10.20998/2079-3944.2021.2.01
L. Zhorniak, A. Afanasiev, Vitaliy Schus, Olexij Morozov, Julia Rudenko
In the article, the authors propose a method for estimating the parameters of theoretical distributions for calculating the indicators of operational reliability. In the article, the authors propose a method for estimating the parameters of theoretical distributions for calculating the indicators of the operational reliability of a solid insulating structure of high-voltage devices, which is a supporting insulating cover for high voltage instrument transformers filled with gas as an insulating liquid. This technique makes it possible to estimate the parameters of a new distribution law, which is chosen on the condition that it does not contradict the existing distribution law with its known parameters. The developed technique makes it possible to obtain the values of the indicators of the operational reliability of high-voltage equipment by determining the parameters of theoretical distributions, if the developer is the data of experimental studies or statistical information as a result of monitoring the operation of insulating structures, taking into account the actual operating conditions of such high-voltage devices. This makes it possible to take into account the influence of external factors and performance characteristics inherent in instrument transformers, both current and voltage. In the proposed methodology, as an example, a supporting insulating casing is considered, which is during operation in the most unfavorable conditions, such as external pollution, humidification, overvoltage, etc. The theoretical conclusions are confirmed by the results of calculations using the example of the design of a current transformer of the ТОГ-362 series. A more accurate determination of the effectiveness of the proposed method for predicting the parameters of theoretical distribution laws can be achieved by performing an additional series of calculations and experimental tests of specific insulating structures. Thus, it was concluded that it is possible to use the results obtained to assess the operational reliability of both gas-filled instrument transformers and similar high-voltage equipment.
{"title":"Estimation peculiarities of external polymer insulation reliability of gas-filled instrument transformers","authors":"L. Zhorniak, A. Afanasiev, Vitaliy Schus, Olexij Morozov, Julia Rudenko","doi":"10.20998/2079-3944.2021.2.01","DOIUrl":"https://doi.org/10.20998/2079-3944.2021.2.01","url":null,"abstract":"In the article, the authors propose a method for estimating the parameters of theoretical distributions for calculating the indicators of operational reliability. In the article, the authors propose a method for estimating the parameters of theoretical distributions for calculating the indicators of the operational reliability of a solid insulating structure of high-voltage devices, which is a supporting insulating cover for high voltage instrument transformers filled with gas as an insulating liquid. This technique makes it possible to estimate the parameters of a new distribution law, which is chosen on the condition that it does not contradict the existing distribution law with its known parameters. The developed technique makes it possible to obtain the values of the indicators of the operational reliability of high-voltage equipment by determining the parameters of theoretical distributions, if the developer is the data of experimental studies or statistical information as a result of monitoring the operation of insulating structures, taking into account the actual operating conditions of such high-voltage devices. This makes it possible to take into account the influence of external factors and performance characteristics inherent in instrument transformers, both current and voltage. In the proposed methodology, as an example, a supporting insulating casing is considered, which is during operation in the most unfavorable conditions, such as external pollution, humidification, overvoltage, etc. The theoretical conclusions are confirmed by the results of calculations using the example of the design of a current transformer of the ТОГ-362 series. A more accurate determination of the effectiveness of the proposed method for predicting the parameters of theoretical distribution laws can be achieved by performing an additional series of calculations and experimental tests of specific insulating structures. Thus, it was concluded that it is possible to use the results obtained to assess the operational reliability of both gas-filled instrument transformers and similar high-voltage equipment.","PeriodicalId":385206,"journal":{"name":"Bulletin of NTU \"KhPI\". Series: Problems of Electrical Machines and Apparatus Perfection. The Theory and Practice","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134130858","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 : 2021-12-09DOI: 10.20998/2079-3944.2021.2.05
V. Kortunov, A. Masliennikov, Andrii Yehorov, O. Duniev
This article deals with a commercially available direct drive brushless DC motor that was investigated in the generator mode at an increased speed above the rated one. During the conducted experiments the increase of the generator rotational speed was carried out due to a three-phase asynchronous motor with 5.5 kW rated power and 2920 rpm rated speed, which was further increased by a two-stage belt gearbox with a reduction ratio from 0.16 to 1.6. However, with an increase in the rotational speed, the magnetic losses also increase, which in turn increase the required value of the input mechanical power and lead to thermal overload of the brushless DC machine. An increase the generator rotational speed leads to an increase of the EMF value and, at the same value, of the stator current, leads to an increase the generated power. Throughout the experiment, the voltage was rectified using a diode bridge and bulk capacitor, after that it was connected to a load resistance. The presented calculations of the magnetic power losses for different electrical steel grades clearly demonstrate the nonlinear dependence between the magnetic field frequency and its magnitude. Experimental studies were carried out at different speeds of rotation of a brushless DC machine in a very wide range from 140 rpm to 5228 rpm, moreover, the values of the output power were obtained depending on the rotational speed. It is concluded, that in the generator mode of the brushless DC machine, it is necessary to take into account the feature of the operation at wind power plants, autonomous power supply such as hybrid power plants. In the first case, it is worth limiting the rotational speed from the driven mechanism, and in the second case, this mode of operation may be necessary for partial boosting of output power for short-term use.
{"title":"Experimental investigation of the generator mode for a brushless dc motor at an increased rotational speed","authors":"V. Kortunov, A. Masliennikov, Andrii Yehorov, O. Duniev","doi":"10.20998/2079-3944.2021.2.05","DOIUrl":"https://doi.org/10.20998/2079-3944.2021.2.05","url":null,"abstract":"This article deals with a commercially available direct drive brushless DC motor that was investigated in the generator mode at an increased speed above the rated one. During the conducted experiments the increase of the generator rotational speed was carried out due to a three-phase asynchronous motor with 5.5 kW rated power and 2920 rpm rated speed, which was further increased by a two-stage belt gearbox with a reduction ratio from 0.16 to 1.6. However, with an increase in the rotational speed, the magnetic losses also increase, which in turn increase the required value of the input mechanical power and lead to thermal overload of the brushless DC machine. An increase the generator rotational speed leads to an increase of the EMF value and, at the same value, of the stator current, leads to an increase the generated power. Throughout the experiment, the voltage was rectified using a diode bridge and bulk capacitor, after that it was connected to a load resistance. The presented calculations of the magnetic power losses for different electrical steel grades clearly demonstrate the nonlinear dependence between the magnetic field frequency and its magnitude. Experimental studies were carried out at different speeds of rotation of a brushless DC machine in a very wide range from 140 rpm to 5228 rpm, moreover, the values of the output power were obtained depending on the rotational speed. It is concluded, that in the generator mode of the brushless DC machine, it is necessary to take into account the feature of the operation at wind power plants, autonomous power supply such as hybrid power plants. In the first case, it is worth limiting the rotational speed from the driven mechanism, and in the second case, this mode of operation may be necessary for partial boosting of output power for short-term use.","PeriodicalId":385206,"journal":{"name":"Bulletin of NTU \"KhPI\". Series: Problems of Electrical Machines and Apparatus Perfection. The Theory and Practice","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117235937","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 : 2021-12-09DOI: 10.20998/2079-3944.2021.2.09
Ivan Kostjukov
The article provides an overview of the most common methods for monitoring the technical state of electrical insulation, based on the applying of absorption phenomena arising in dielectric materials under the influence of DC voltage. The main provisions of the control method based on determining the voltage at the electrodes of the investigated capacitive control object, which is recovering after a short-term discharge of its capacity, are described. The main aspects of the application of the polarization index and the absorption coefficient for determining the technical state of insulation by using the coefficients characterizing the change in time of the current through the dielectric when a constant test voltage is applied to it are analyzed. The advantages of using absorption methods for monitoring the technical state of electrical insulation, first of all, are the ability to carry out testing without the necessity of applying of relatively high test voltages, which greatly simplifies all the necessary technical operations. Such control methods show a significant dependence of the informative parameters used in them on the technical state of insulation on the degree of development of slow polarization processes in the material under study and, therefore, are successfully used to determine the degree of moisture in tested electrical insulation.
{"title":"Absorption methods of control of technical condition of electrical insulation","authors":"Ivan Kostjukov","doi":"10.20998/2079-3944.2021.2.09","DOIUrl":"https://doi.org/10.20998/2079-3944.2021.2.09","url":null,"abstract":"The article provides an overview of the most common methods for monitoring the technical state of electrical insulation, based on the applying of absorption phenomena arising in dielectric materials under the influence of DC voltage. The main provisions of the control method based on determining the voltage at the electrodes of the investigated capacitive control object, which is recovering after a short-term discharge of its capacity, are described. The main aspects of the application of the polarization index and the absorption coefficient for determining the technical state of insulation by using the coefficients characterizing the change in time of the current through the dielectric when a constant test voltage is applied to it are analyzed. The advantages of using absorption methods for monitoring the technical state of electrical insulation, first of all, are the ability to carry out testing without the necessity of applying of relatively high test voltages, which greatly simplifies all the necessary technical operations. Such control methods show a significant dependence of the informative parameters used in them on the technical state of insulation on the degree of development of slow polarization processes in the material under study and, therefore, are successfully used to determine the degree of moisture in tested electrical insulation.","PeriodicalId":385206,"journal":{"name":"Bulletin of NTU \"KhPI\". Series: Problems of Electrical Machines and Apparatus Perfection. The Theory and Practice","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131317224","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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