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Analysis of Mechanical Stress during Short Circuit in an Air-Insulated MV Switchgear
Bártů, Jan ; Bajánek, Tomáš (referee) ; Orságová, Jaroslava (advisor)
This Master thesis is based on problems of force effects of the magnetic field of short-circuit current. Firstly, I analysed the force action of the three phase busbars during the three-pole short circuit. The analysis was performed in the Ansys Maxwell program and I verified the correctness of the analysis by numerical calculation. The second practical part was executed for ABB company. The main task was to analyse the force effects of the short-circuit current in the HV switchgear with focusing on the arms and contact system of the circuit breaker. The simulations of the following configurations were performed in more details: three configurations of the simplified VD4 circuit breaker, two types of VD4 circuit-breaker contact systems and a linear circuit breaker configuration model. The objective was to calculate the forces acting on the current path of the arms and contact system of the VD4 circuit breaker during the three-phase short-circuit and to simulate the effects of forces on these current parts. For modelling of individual assemblies, calculations and simulations I used: SolidWorks 2014, Ansys Maxwell 16.0 and Ansys Workbench 14.5 programs. With SolidWorks 2014 3D CAD software were modelled simplified assemblies of circuit breakers and contact systems. These systems were imported into the Ansys Maxwell software, where the force effects of the magnetic field of the short-circuit current were calculated. In Ansys Workbench programme was simulated the effect of forces on the current circuit breakers. Moreover, the final deformations of the materials (with respect to the mechanical properties of the structure) were plotted. The analysis of force effects of the magnetic field was performed for the specified static short - circuit current value.
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Dielectric properties of epoxy resins
Matoušová, Klára ; Novák, Vítězslav (referee) ; Kazelle, Jiří (advisor)
This diploma thesis deals with the fundamental properties of epoxide mixtures, as determining of these fundamental properties of epoxide mixtures could in the case of favorable results lead to diminishing the amount of defects in epoxide-embedded instrument transformers. As the influence of effects in the manufacturing process of transformers causing poor quality is very extensit, the biggest emphasis is laid capitally on the influence of the epoxide casting mixture composition. The thesis describes the manufacture technology including used methodics and materials. The compositions of epoxide resins and the mechanisms of their curing. Also, the definitions of fundamental properties of dielectric materials and the description of diagnostic methods used to relative permitivity, dissipation factor and inner resistivity are included. suitable casts of acquired samples were set and dried out within the experimental part, followed by measurement of fundamental electrical properties in temperature and frequency relations. Hereafter a comparison of individual samples and the evaluation of their electrical properties will be carried out.
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Drying and preheating in potting process of epoxides
Matoušová, Klára ; Novák, Vítězslav (referee) ; Kazelle, Jiří (advisor)
The bachelor's thesis is dealing with the defects in epoxy resin flooded transformer devices. Since these can be damaged severely in terms of quality by numerous forces, the main focus is dedicated to the impact of moisture. The thesis describes the manufacturing technology including the methods applied and materials used. It further encompasses the composition of epoxy resin and the mechanisms used for their hardening processes. Additionally, the description of the moisture, the impact of adverse forces and the method of their elimination using drying is presented. In the experimental part of the paper, a moisture of the banding materials was measured. On the basis of the results acquired, the paper reaches a conclusion on the ideal time frame of drying, the sufficiency of materials in terms of drying and in two cases two substitutes for contemporary uneasily dryable samples were considered.
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Dielectric properties of epoxy resins
Matoušová, Klára ; Novák, Vítězslav (referee) ; Kazelle, Jiří (advisor)
This diploma thesis deals with the fundamental properties of epoxide mixtures, as determining of these fundamental properties of epoxide mixtures could in the case of favorable results lead to diminishing the amount of defects in epoxide-embedded instrument transformers. As the influence of effects in the manufacturing process of transformers causing poor quality is very extensit, the biggest emphasis is laid capitally on the influence of the epoxide casting mixture composition. The thesis describes the manufacture technology including used methodics and materials. The compositions of epoxide resins and the mechanisms of their curing. Also, the definitions of fundamental properties of dielectric materials and the description of diagnostic methods used to relative permitivity, dissipation factor and inner resistivity are included. suitable casts of acquired samples were set and dried out within the experimental part, followed by measurement of fundamental electrical properties in temperature and frequency relations. Hereafter a comparison of individual samples and the evaluation of their electrical properties will be carried out.
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Analysis of Mechanical Stress during Short Circuit in an Air-Insulated MV Switchgear
Bártů, Jan ; Bajánek, Tomáš (referee) ; Orságová, Jaroslava (advisor)
This Master thesis is based on problems of force effects of the magnetic field of short-circuit current. Firstly, I analysed the force action of the three phase busbars during the three-pole short circuit. The analysis was performed in the Ansys Maxwell program and I verified the correctness of the analysis by numerical calculation. The second practical part was executed for ABB company. The main task was to analyse the force effects of the short-circuit current in the HV switchgear with focusing on the arms and contact system of the circuit breaker. The simulations of the following configurations were performed in more details: three configurations of the simplified VD4 circuit breaker, two types of VD4 circuit-breaker contact systems and a linear circuit breaker configuration model. The objective was to calculate the forces acting on the current path of the arms and contact system of the VD4 circuit breaker during the three-phase short-circuit and to simulate the effects of forces on these current parts. For modelling of individual assemblies, calculations and simulations I used: SolidWorks 2014, Ansys Maxwell 16.0 and Ansys Workbench 14.5 programs. With SolidWorks 2014 3D CAD software were modelled simplified assemblies of circuit breakers and contact systems. These systems were imported into the Ansys Maxwell software, where the force effects of the magnetic field of the short-circuit current were calculated. In Ansys Workbench programme was simulated the effect of forces on the current circuit breakers. Moreover, the final deformations of the materials (with respect to the mechanical properties of the structure) were plotted. The analysis of force effects of the magnetic field was performed for the specified static short - circuit current value.
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Drying and preheating in potting process of epoxides
Matoušová, Klára ; Novák, Vítězslav (referee) ; Kazelle, Jiří (advisor)
The bachelor's thesis is dealing with the defects in epoxy resin flooded transformer devices. Since these can be damaged severely in terms of quality by numerous forces, the main focus is dedicated to the impact of moisture. The thesis describes the manufacturing technology including the methods applied and materials used. It further encompasses the composition of epoxy resin and the mechanisms used for their hardening processes. Additionally, the description of the moisture, the impact of adverse forces and the method of their elimination using drying is presented. In the experimental part of the paper, a moisture of the banding materials was measured. On the basis of the results acquired, the paper reaches a conclusion on the ideal time frame of drying, the sufficiency of materials in terms of drying and in two cases two substitutes for contemporary uneasily dryable samples were considered.
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