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Bill G. Macfarlane - One of the best experts on this subject based on the ideXlab platform.
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Transformer failure due to Circuit-breaker-induced switching transients
IEEE Transactions on Industry Applications, 2011Co-Authors: David D. Shipp, Visuth Lorch, Thomas J. Dionise, Bill G. MacfarlaneAbstract:Switching transients associated with Circuit breakers have been observed for many years. Recently, this phenomenon has been attributed to a significant number of transformer failures involving Primary Circuit-breaker switching. These transformer failures had common contributing factors such as the following: 1) Primary vacuum or SF-6 breaker; 2) short cable or bus con- nection to transformer; and 3) application involving dry-type or cast-coil transformers and some liquid-filled ones. This paper will review these recent transformer failures due to Primary Circuit- breaker switching transients to show the severity of damage caused by the voltage surge and discuss the common contributing factors. Next, switching transient simulations in the electromag- netic transients program will give case studies which illustrate how breaker characteristics of current chopping and restrike combine with critical Circuit characteristics to cause transformer failure. Design and installation considerations will be addressed, particularly the challenges of retrofitting a snubber to an exist- ing facility with limited space. Finally, several techniques and equipment that have proven to successfully mitigate the breaker switching transients will be presented, including surge arresters, surge capacitors, snubbers, and these in combination.
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transformer failure due to Circuit breaker induced switching transients
Pulp and Paper Industry Conference, 2010Co-Authors: David D. Shipp, Visuth Lorch, Thomas J. Dionise, Bill G. MacfarlaneAbstract:Switching transients associated with Circuit breakers have been observed for many years. Recently this phenomenon has been attributed to a significant number of transformer failures involving Primary Circuit breaker switching. These transformer failures had common contributing factors such as 1) Primary vacuum or SF-6 breaker, 2) short cable or bus connection to transformer, and 3) application involving dry-type or cast coil transformers and some liquid filled. This paper will review these recent transformer failures due to Primary Circuit breaker switching transients to show the severity of damage caused by the voltage surge and discuss the common contributing factors. Next, switching transient simulations in the electromagnetic transients program (EMTP) will give case studies which illustrate how breaker characteristics of current chopping and re-strike combine with critical Circuit characteristics to cause transformer failure. Design and installation considerations will be addressed, especially the challenges of retrofitting a snubber to an existing facility with limited space. Finally, several techniques and equipment that have proven to successfully mitigate the breaker switching transients will be presented including surge arresters, surge capacitors, snubbers and these in combination.
Barale Morgan - One of the best experts on this subject based on the ideXlab platform.
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Etude du comportement des particules colloïdale dans les conditions physico-chimiques du Circuit primaire des réacteurs à eau sous pression
HAL CCSD, 2006Co-Authors: Barale MorganAbstract:EDF wants to understand, model and limit Primary Circuit contamination of Pressurized Water Reactors by colloidal particles resulting from corrosion. The electrostatic behaviour of representative oxide particles (cobalt ferrite, nickel ferrite and magnetite) has been studied in Primary Circuit conditions with the influence of boric acid and lithium hydroxide. The isoelectric point (IEP) and the point of zero charge (PZC) of particles, measured between 5°C and 320°C, exhibit a minimum towards 200°C. The thermodynamic constants of the protonation equilibrium of surface sites were calculated. When boric acid is added, zeta potential and IEP decrease because of borate ions sorption. On the contrary, there is not effect of lithium ions. The modelling of these results under conditions representative of Primary Circuit shows that these oxides exhibit a negative surface charge, explaining their sorption and adhesion behaviour.Cette thèse s'inscrit dans un programme initié par EDF afin de comprendre, de modéliser et de limiter la contamination du Circuit primaire des réacteurs à eau sous pression par des particules colloïdales issues de la corrosion. Le comportement électrostatique de particules d'oxydes représentatives (ferrite de cobalt (CoFe2O4), ferrite de nickel (NiFe2O4) et la magnétite (Fe3O4)) a été étudié dans les conditions physico-chimiques du Circuit primaire : en température (jusqu'à 320°C), en présence d'acide borique B(OH)3 et de lithine LiOH. Le point isoélectrique (PIE) et le point de charge nulle (PZC), mesurés entre 5 et 320°C, présentent, comme le pKe de l'eau, un minimum vers 200°C. Les constantes thermodynamiques de protonation ont été calculées. Le potentiel zêta et le PIE diminuent en présence d'acide borique, à cause de la sorption d'ions borate. La lithine n'a pas d'effet marqué. La modélisation de ces résultats dans des conditions représentatives du Circuit primaire montre que ce type d'oxydes a une surface négative ce qui explique leurs propriétés de sorption et d'adhésion
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Etude du comportement des particules colloidales dans les conditions physico-chimiques du Circuit primaire des réacteurs à eau sous pression
2006Co-Authors: Barale Morgan, Cote GérardAbstract:Cette thèse s inscrit dans un programme initié par EDF afin de comprendre, de modéliser et de limiter la contamination du Circuit primaire des réacteurs à eau sous pression par des particules colloïdales issues de la corrosion. Le comportement électrostatique de particules d oxydes représentatives (ferrite de cobalt (CoFe2O4), ferrite de nickel (NiFe2O4) et la magnétite (Fe3O4)) a été étudié dans les conditions physico-chimiques du Circuit primaire : en température (jusqu à 320C), en présence d acide borique B(OH)3 et de lithine LiOH. Le point isoélectrique (PIE) et le point de charge nulle (PZC), mesurés entre 5 et 320C, présentent, comme le pKe de l eau, un minimum vers 200C. Les constantes thermodynamiques de protonation ont été calculées. Le potentiel zêta et le PIE diminuent en présence d acide borique, à cause de la sorption d ions borate. La lithine n a pas d effet marqué. La modélisation de ces résultats dans des conditions représentatives du Circuit primaire montre que ce type d oxydes a une surface négative ce qui explique leurs propriétés de sorption et d adhésion.EDF wants to understand, model and limit Primary Circuit contamination of Pressurized Water Reactors by colloidal particles resulting from corrosion. The electrostatic behaviour of representative oxide particles (cobalt ferrite, nickel ferrite and magnetite) has been studied in Primary Circuit conditions with the influence of boric acid and lithium hydroxide. The isoelectric point (IEP) and the point of zero charge (PZC) of particles, measured between 5C and 320C, exhibit a minimum towards 200C. The thermodynamic constants of the protonation equilibrium of surface sites were calculated. When boric acid is added, zeta potential and IEP decrease because of borate ions sorption. On the contrary, there is not effect of lithium ions. The modelling of these results under conditions representative of Primary Circuit shows that these oxides exhibit a negative surface charge, explaining their sorption and adhesion behaviour.PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF
David D. Shipp - One of the best experts on this subject based on the ideXlab platform.
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Transformer failure due to Circuit-breaker-induced switching transients
IEEE Transactions on Industry Applications, 2011Co-Authors: David D. Shipp, Visuth Lorch, Thomas J. Dionise, Bill G. MacfarlaneAbstract:Switching transients associated with Circuit breakers have been observed for many years. Recently, this phenomenon has been attributed to a significant number of transformer failures involving Primary Circuit-breaker switching. These transformer failures had common contributing factors such as the following: 1) Primary vacuum or SF-6 breaker; 2) short cable or bus con- nection to transformer; and 3) application involving dry-type or cast-coil transformers and some liquid-filled ones. This paper will review these recent transformer failures due to Primary Circuit- breaker switching transients to show the severity of damage caused by the voltage surge and discuss the common contributing factors. Next, switching transient simulations in the electromag- netic transients program will give case studies which illustrate how breaker characteristics of current chopping and restrike combine with critical Circuit characteristics to cause transformer failure. Design and installation considerations will be addressed, particularly the challenges of retrofitting a snubber to an exist- ing facility with limited space. Finally, several techniques and equipment that have proven to successfully mitigate the breaker switching transients will be presented, including surge arresters, surge capacitors, snubbers, and these in combination.
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transformer failure due to Circuit breaker induced switching transients
Pulp and Paper Industry Conference, 2010Co-Authors: David D. Shipp, Visuth Lorch, Thomas J. Dionise, Bill G. MacfarlaneAbstract:Switching transients associated with Circuit breakers have been observed for many years. Recently this phenomenon has been attributed to a significant number of transformer failures involving Primary Circuit breaker switching. These transformer failures had common contributing factors such as 1) Primary vacuum or SF-6 breaker, 2) short cable or bus connection to transformer, and 3) application involving dry-type or cast coil transformers and some liquid filled. This paper will review these recent transformer failures due to Primary Circuit breaker switching transients to show the severity of damage caused by the voltage surge and discuss the common contributing factors. Next, switching transient simulations in the electromagnetic transients program (EMTP) will give case studies which illustrate how breaker characteristics of current chopping and re-strike combine with critical Circuit characteristics to cause transformer failure. Design and installation considerations will be addressed, especially the challenges of retrofitting a snubber to an existing facility with limited space. Finally, several techniques and equipment that have proven to successfully mitigate the breaker switching transients will be presented including surge arresters, surge capacitors, snubbers and these in combination.
Kazuhiro Sawa - One of the best experts on this subject based on the ideXlab platform.
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fuel and fission gas behavior during rise to power test of the high temperature engineering test reactor httr
Journal of Nuclear Science and Technology, 2003Co-Authors: Shohei Ueta, Junya Sumita, Koichi Emori, Masashi Takahashi, Kazuhiro SawaAbstract:The rise-to-power tests of the High Temperature Engineering Test Reactor (HTTR) have been carried out successfully by the Japan Atomic Energy Research Institute (JAERI). For the safe operation of HTTR, the continuous and reliable measurement of the coolant activity is required to evaluate the fuel performance during normal operating conditions. In order to measure the Primary coolant radioactivity (PCR), the PCR instrumentation of the safety protection system, the fuel failure detection (FFD) system and the Primary coolant sampling system have been installed in the Primary Circuit. The PCR was less than 103 MBq/m3, and measured Kr and Xe isotopes were less than 0.1 MBq/m3 during the rise-to-power tests. The measured fractional releases are constant at 2x10-9 up to 60% of the reactor power, and then increase to 7x10-9 at full power operation. The prediction shows good agreement with the measured value. These results showed that the release mechanism varied from recoil to diffusion of the generated fission ...
Lei Shi - One of the best experts on this subject based on the ideXlab platform.
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analysis on blow down transient in water ingress accident of high temperature gas cooled reactor
Nuclear Engineering and Design, 2014Co-Authors: Yan Wang, Yanhua Zheng, Lei ShiAbstract:Abstract Water ingress into the Primary Circuit is generally recognized as one of the severe accidents with potential hazard to the modular high temperature gas-cooled reactor, which will cause a positive reactivity introduction with the increase of steam density in reactor core to enhance neutron slowing-down, also the chemical corrosion of graphite fuel elements and the damage of reflector structure material. The increase of the Primary pressure may result in the opening of the safety valves, consequently leading the release of radioactive isotopes and flammable water gas. The research on water ingress transient is significant for the verification of inherent safety characteristics of high temperature gas-cooled reactor. The 200 MWe high temperature gas-cooled reactor (HTR-PM), designed by the Institute of Nuclear and New Energy Technology of Tsinghua University, is exampled to be analyzed in this paper. The design basis accident (DBA) scenarios of double-ended guillotine break of single heat-exchange tube (steam generator heat-exchange tube rupture) are simulated by the thermal-hydraulic analysis code, and some key concerns which are relative to the amount of water into the reactor core during the blow-down transient are analyzed in detail. The results show that both of water mass and steam ratio of the fluid spouting from the broken heat-exchange tube are affected by break location, which will increase obviously with the broken location closing to the outlet of the heat-exchange tube. The double-ended guillotine rupture at the outlet of the heat-exchange will result more steam penetrates into the reactor core in the design basis accident of water ingress. The mass of water ingress will also be affected by the draining system. It is concluded that, with reasonable optimization on design to balance safety and economy, the total mass of water ingress into the Primary Circuit of reactor could be limited effectively to meet the safety requirements, and the pollution of radioactive isotopes releasing to the secondary Circuit during the blow-down transient will be prevented.