Calculation of the uniform breakdown field strength of SF/sub 6/ gas

Cliteur, G J; Hayashi, Yuichiro; Haginomori, Eiichi; Suzuki, Koji

doi:10.1109/94.740765

Cited by 71 publications

(59 citation statements)

References 18 publications

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“…The dielectric strength of the gas gap between the contacts is important at some ms after CZ, when the recovery voltage of the network stresses the gap. The electric field strength before breakdown of SF6 decreases strongly for temperatures above 1500K, where the dissociation of SF6 starts [25]. The size of the chosen heating volume thus mainly depends on the rated short-circuit currents, the maximum allowable temperature, and the mechanical stability of the design.…”

Section: Pressure Build-upmentioning

confidence: 99%

Application of High Current and Current Zero Simulations of High‐Voltage Circuit Breakers

Franck

Seeger

2006

Contrib. Plasma Phys.

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This paper reports on the use of computational fluid dynamic (CFD) simulations to predict the interruption behaviour of high-voltage circuit breakers (HV-CB) using the self-blast principle. Two different levels of accuracy of the arc model are proven to be sufficiently accurate for simulating the high-current phase and the period around current zero (CZ). For the high-current phase, a simplified equivalent model of the arc is implemented to predict the pressure build-up, and even more important to accurately trace the hot gas from the arcing zone into the exhausts and the heating volume. A detailed analysis of the gas mixing in the heating volume for different arcing times and current amplitudes showed the optimum geometrical design of the heating volume. For the CZ phase, a more detailed arc model is needed including the effects of ohmic heating, radiative energy transfer, and turbulent cooling fully resolved in space and time. The validation with experiments was done and shows good agreement which justifies the use of the implemented model. With it, scaling laws varying only one parameter at a time (pressure and applied current slope) were derived and confirm previously found empirical laws. This is of particular interest, as it is very difficult to derive such scaling laws from experiments where the scatter is always very large and where it is impossible to vary only one parameter at a time. The influence of the most important geometrical parameters of the nozzle on the interruption performance is shown. In addition to previous experimental indications of this, the simulation reveals that turbulent cooling on the arc edge is the main reason for the difference in interruption performance. Moreover, the exact spatio-temporal build-up of arc resistance and with it the detailed understanding of the arc interruption process is possible and shown here for the first time. These simulations enable us to predict HV-CB performance and to minimise the number of development tests and are routinely used in new development projects.

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Section: Pressure Build-upmentioning

confidence: 99%

Application of High Current and Current Zero Simulations of High‐Voltage Circuit Breakers

Franck

Seeger

2006

Contrib. Plasma Phys.

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“…Transient recovery voltages (TRVs), which are higher than operating voltage in the system, are applied to GCBs within several hundreds of microseconds after current zero, then the operating voltage (is applied) continuously. To evaluate dielectric strength, gas density and temperature are significant parameters along with electric field strength [16]- [18]. Fig.…”

Section: B Gas Flow In Exhaust Cylindermentioning

confidence: 99%

Gas-Flow Simulation With Contact Moving in GCB Considering High-Pressure and High-Temperature Transport Properties of SF<tex>$_6$</tex>Gas

Mori¹,

Kawano²,

Iwamoto³

et al. 2005

IEEE Trans. Power Delivery

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Abstract-This paper addresses a thermal gas-flow simulation in gas circuit-breaker (GCB) chambers, introducing SF 6 gas constants up to a pressure of 10 MPa and to a temperature of 30 000 K. In the simulation, moving parts, such as nozzle, movable arcing contact, and operating rod, are moved with the opening motion of GCB to see if different results are produced from the conventional simulation method, in which fixed parts in the real GCB are moved. As a result, as far as the pressure profile in the puffer chamber is concerned, it is confirmed that this simulation method can produce better results than the conventional method for the hybrid-puffer-type chamber.

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“…Figures 6 (a) and (b) show the ratio of induction electric field E f to breakdown electric field E crit as functions of temperature and pressure at imposed TRV. The breakdown electric field is determined by calculation of insulating performance of SF 6 as functions of temperature and pressure (3), (9) . When the ratio becomes less than 1, this region shows safety.…”

Section: Numerical Proceduresmentioning

confidence: 99%

“…There has been a recent problem of hot and high pressure SF 6 exhausted gas breakdown to the grounded tank due to the transient recovery high voltage, when the arc current is interrupted in a compact size of GCB for small SF 6 gas consumption and for underground substation in a big city (2) . This comes from the drastic suppression of insulation performance for hot SF 6 gas in a small tank volume for cooling hot gas flow (3), (4) . To overcome this problem it is necessary to understand the transient behavior of SF 6 gas flow inside the exhaust tube and to cool the SF 6 hot gas more effectively for transient time during current interruption.…”

Section: Introductionmentioning

confidence: 99%

Transient Response Simulation of Downstream Thermofluid Field in a Gas Circuit Breaker during Current Interruption

Nishiyama

Hamada

Uchii

et al. 2005

JSME international journal. Ser. B, Fluids and thermal engineer

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A transient response of SF 6 thermofluid field inside the exhaust tube in a Gas Circuit Breaker under high temperature, high pressure and high velocity conditions is analyzed by taking compressible effect and some realistic processes into account related to the available experimental data of GCB test facility. Furthermore, computational simulation is conducted to clarify the effective cooling process of SF 6 hot gas flow inside the exhaust tube for transient time to avoid the SF 6 hot gas breakdown near exhaust tube exit after the arc current interruption. It is found that the SF 6 hot gas flow can be effectively cooled down for the rough inside wall of exhaust tube due to the separation of SF 6 hot gas flow from the inside wall and also active mixing with upstream cold gas. The effect of roughness pattern on the real time thermofluid field of SF 6 hot gas flow and possible breakdown region are also clarified. Finally, the computed temperature in GCB shows the good agreement with the available experimental data for smooth surface of exhaust tube.

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Calculation of the uniform breakdown field strength of SF/sub 6/ gas

Cited by 71 publications

References 18 publications

Application of High Current and Current Zero Simulations of High‐Voltage Circuit Breakers

Application of High Current and Current Zero Simulations of High‐Voltage Circuit Breakers

Gas-Flow Simulation With Contact Moving in GCB Considering High-Pressure and High-Temperature Transport Properties of SF<tex>$_6$</tex>Gas

Transient Response Simulation of Downstream Thermofluid Field in a Gas Circuit Breaker during Current Interruption

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Calculation of the uniform breakdown field strength of SF/sub 6/ gas

Cited by 71 publications

References 18 publications

Application of High Current and Current Zero Simulations of High‐Voltage Circuit Breakers

Application of High Current and Current Zero Simulations of High‐Voltage Circuit Breakers

Gas-Flow Simulation With Contact Moving in GCB Considering High-Pressure and High-Temperature Transport Properties of SF&lt;tex&gt;$_6$&lt;/tex&gt;Gas

Transient Response Simulation of Downstream Thermofluid Field in a Gas Circuit Breaker during Current Interruption

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Gas-Flow Simulation With Contact Moving in GCB Considering High-Pressure and High-Temperature Transport Properties of SF<tex>$_6$</tex>Gas