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Testing of arc protection AFDD during normal and fault conditions
Křepela, František ; Dostál, Lukáš (referee) ; Kaser, Jakub (advisor)
The bachelor´s thesis deals with AFDD, a device that protects the low voltage electrical installations against fire caused by a serial or parallel arc fault. Although MCB and RCD can mostly disconnect the circuit when the parallel arc appears, only AFDD can detect the series arc fault. AFDD can be used only as additional protection. The theoretical part of this thesis describes the creation of electric arc, causes of house fires, and explains the principle of the Arc Fault Detection Device. The purpose of the practical part is to create real malfunctions that cause a series arc in the circuit and to test the function of AFDD. The next purpose is to repair the arc generator and to verify the function of AFDD using different materials of electrodes.
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Mathematical model of RCCB sensitive to pulsating direct currents
Kaser, Jakub ; Dostál, Lukáš (referee) ; Valenta, Jiří (advisor)
This Thesis deals with problematics of residual current circuit breaker and its eventual operation malfunction due to DC components. There are magnetic phenomena described in details which occur inside of the apparatus. Consequently, there is proposed a mathematical model of the circuit breaker in Simulink program. The comparison of B-H curves of transformer core is composed and achieved results are incorporated into the proposed model in order to verify a correct operation of the circuit breaker and its reaction to different conditions. The verification of the symmetry of the magnetic field in residual current circuit breaker in Ansys Maxwell program is also a part of the study.
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The measurement of bimetal for a switching device
Bartek, Zbyněk ; Bušov, Bohuslav (referee) ; Kaser, Jakub (advisor)
This bachelor thesis deals with the thermal trigger of bimetallic-based safety devices. The theoretical part describes the principle of the function of bimetal, materials and production of bimetal, and important parametres of bimetal including mathematical description. Furthermore the advantages and disadvantages of specific bimetals, types of bimetals and their practical use, and standards dealing with circuit breakers are also described. The last theoretical part of the work describe basic calculations for the design of bimetal. In the practical part were measured the free deflection of the bimetals, the results obtained were processed into graphic dependencies and compared with theoretical values.
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Mathematical Model of RCCB Sensitive to Pulsating Direct Currents
Kaser, J. ; Valenta, J.
This study is focused on a residual-current circuit breaker (RCCB) and its eventual operation malfunction due to direct current components. This problem is associated with magnetic phenomena inside its transformer core. These phenomena are described in detail in the magnetic equations used in a mathematical model created in Simulink. The model incorporates the comparison of individual transformer B/H loop and verifies its reaction to the various residual currents and the correct operation of residual current circuit breaker to achieve results.
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Testing of arc protection AFDD during normal and fault conditions
Křepela, František ; Dostál, Lukáš (referee) ; Kaser, Jakub (advisor)
The bachelor´s thesis deals with AFDD, a device that protects the low voltage electrical installations against fire caused by a serial or parallel arc fault. Although MCB and RCD can mostly disconnect the circuit when the parallel arc appears, only AFDD can detect the series arc fault. AFDD can be used only as additional protection. The theoretical part of this thesis describes the creation of electric arc, causes of house fires, and explains the principle of the Arc Fault Detection Device. The purpose of the practical part is to create real malfunctions that cause a series arc in the circuit and to test the function of AFDD. The next purpose is to repair the arc generator and to verify the function of AFDD using different materials of electrodes.
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Topology And Breaking Process Of Hybrid Dc Circuit Breaker
Kaser, Jakub
This study is focused on a general function of hybrid direct current circuit breakers. Theone of topics is design topology of these circuit breakers with all necessary branches. Mainly, thestudy deal with their principles of interruption of fault direct current. The description of issue is ingeneral and then for the specific interesting proposals. The main purpose of these protections iscontinuous reducing the fault current to the current-zero outside the mechanical breaker contactswhich conduct solely the nominal current.
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The measurement of bimetal for a switching device
Bartek, Zbyněk ; Bušov, Bohuslav (referee) ; Kaser, Jakub (advisor)
This bachelor thesis deals with the thermal trigger of bimetallic-based safety devices. The theoretical part describes the principle of the function of bimetal, materials and production of bimetal, and important parametres of bimetal including mathematical description. Furthermore the advantages and disadvantages of specific bimetals, types of bimetals and their practical use, and standards dealing with circuit breakers are also described. The last theoretical part of the work describe basic calculations for the design of bimetal. In the practical part were measured the free deflection of the bimetals, the results obtained were processed into graphic dependencies and compared with theoretical values.
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Mathematical model of RCCB sensitive to pulsating direct currents
Kaser, Jakub ; Dostál, Lukáš (referee) ; Valenta, Jiří (advisor)
This Thesis deals with problematics of residual current circuit breaker and its eventual operation malfunction due to DC components. There are magnetic phenomena described in details which occur inside of the apparatus. Consequently, there is proposed a mathematical model of the circuit breaker in Simulink program. The comparison of B-H curves of transformer core is composed and achieved results are incorporated into the proposed model in order to verify a correct operation of the circuit breaker and its reaction to different conditions. The verification of the symmetry of the magnetic field in residual current circuit breaker in Ansys Maxwell program is also a part of the study.
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