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Design of instrument transformers for digital protection relays
Souček, Jan ; Matuška, Marcel (referee) ; Toman, Petr (advisor)
Master’s thesis is concerned with instrument transformers, which are used in conjunction with numerical protection relays. Therefore mainly with protective transformers of class P and transformers dimensioned for transient effects, which are important e.g. for fast differential or distance protections. The introduction includes fundamental notions, quantities and equations, which refers to instrumental current and voltage transformers. Below are mentioned connection diagrams of these transformers applied to specific electrical network types and faults, of which identification is required. These diagrams and faults are supplied with math equations and eventually with phasor diagrams. Noted informations corresponds to the present standards. Task of the next part is to compile requirements for dimensioning of current transformers, which imposes digital protections from ABB, AREVA and Siemens companies. These requirements, which mostly defines the minimal accuracy limit factor or the knee-point voltage of current transformer, are specified for individual protection terminals, eventually for specific protective functions. Part of the thesis is computer program developed as macro in the Microsoft Office Excel program via Visual Basic for Applications programming language. Program uses equations noted in this work and it can be used for quick dimensioning of current transformers for protective terminals from manufactures mentioned above.
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Protection of Transformer by Differential Relay
Jára, Jaroslav ; Haluzík, Evžen (referee) ; Toman, Petr (advisor)
This bachelor’s thesis deals with transformer failures and principles of their protection and a design of differential protection of transformers. The first part details with transformer failures, classification of these failures, short-circuit ground faults types, causes of the short-circuit occurrences and consequences of oil-transformer failures. The second part deals with problems of protection in general with the description of protection function, requirements of protection such as selectivity, speed of response, sensitivity and protection classification, methods of protection according to failure type - size of nominal power of transformers. It further describes principle of differential protections. Finally there are previews of historical and modern protections. The third part describes a design of differential protection of transformers. It includes short-circuit ratio calculation, example of three phase short-circuit calculation, CT ratio check, actual setting of protection and setting evaluation.
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Current transformers 12kV, 4000 / / 5/5A
Šumberák, David ; Vaněk, Jaromír (referee) ; Dostál, Lukáš (advisor)
This master´s thesis describes the development proposal and production of instrument current transformer in one turn primary winding with 4000//5/5 A transfer. The thesis involves a theoretical analysis, a numerical calculation, a developmental 3D model, corresponding simulations and a standard testing of the transformers. There is a complete written description of measuring current transformer cycle from the development to the production. The transformer development and production works were collaborated with the company KPB Intra s.r.o. The company engages in development, production and sale of these kinds of instrument transformers in the Czech Republic and foreign markets.
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Protection of Transformer by Differential Relay
Jára, Jaroslav ; Haluzík, Evžen (referee) ; Toman, Petr (advisor)
This bachelor’s thesis deals with transformer failures and principles of their protection and a design of differential protection of transformers. The first part details with transformer failures, classification of these failures, short-circuit ground faults types, causes of the short-circuit occurrences and consequences of oil-transformer failures. The second part deals with problems of protection in general with the description of protection function, requirements of protection such as selectivity, speed of response, sensitivity and protection classification, methods of protection according to failure type - size of nominal power of transformers. It further describes principle of differential protections. Finally there are previews of historical and modern protections. The third part describes a design of differential protection of transformers. It includes short-circuit ratio calculation, example of three phase short-circuit calculation, CT ratio check, actual setting of protection and setting evaluation.
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Current transformers 12kV, 4000 / / 5/5A
Šumberák, David ; Vaněk, Jaromír (referee) ; Dostál, Lukáš (advisor)
This master´s thesis describes the development proposal and production of instrument current transformer in one turn primary winding with 4000//5/5 A transfer. The thesis involves a theoretical analysis, a numerical calculation, a developmental 3D model, corresponding simulations and a standard testing of the transformers. There is a complete written description of measuring current transformer cycle from the development to the production. The transformer development and production works were collaborated with the company KPB Intra s.r.o. The company engages in development, production and sale of these kinds of instrument transformers in the Czech Republic and foreign markets.
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|
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Design of instrument transformers for digital protection relays
Souček, Jan ; Matuška, Marcel (referee) ; Toman, Petr (advisor)
Master’s thesis is concerned with instrument transformers, which are used in conjunction with numerical protection relays. Therefore mainly with protective transformers of class P and transformers dimensioned for transient effects, which are important e.g. for fast differential or distance protections. The introduction includes fundamental notions, quantities and equations, which refers to instrumental current and voltage transformers. Below are mentioned connection diagrams of these transformers applied to specific electrical network types and faults, of which identification is required. These diagrams and faults are supplied with math equations and eventually with phasor diagrams. Noted informations corresponds to the present standards. Task of the next part is to compile requirements for dimensioning of current transformers, which imposes digital protections from ABB, AREVA and Siemens companies. These requirements, which mostly defines the minimal accuracy limit factor or the knee-point voltage of current transformer, are specified for individual protection terminals, eventually for specific protective functions. Part of the thesis is computer program developed as macro in the Microsoft Office Excel program via Visual Basic for Applications programming language. Program uses equations noted in this work and it can be used for quick dimensioning of current transformers for protective terminals from manufactures mentioned above.
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