• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1559-1561
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• 1994

At present, the principle of puffer action in high current interruption is adopted in almost of the EHV(Extra High Voltage) and UHV(Ultra High Voltage) GCB(Gas Circuit Breakers). The thermal interruption capability of these GCBs critically depends on the pressure rise in the puffer cylinder at current zero. The pressure rise in the puffer cylinder depends on the puffer cylinder volume, flow passage and leakage area in the interrupter, stroke curve etc. Recently commercial CFD(Computational Fluid Dynamics ) packages have been widely adopted to calculate the pressure distribution in the interrupter. However, there are still several problems with it, e.g. very expensive price, moving boundary problem, computation time, difficulty in using the package etc. Thus, the calculation of the puffer cylinder pressure in simple and relatively correct method is essential in early stage of GCB design. In these paper, the model ing technique and computed results for EHV class GCB (HICO, 145kV 40kA and 362kV 40kA GCB) are presented and compared with available measured results.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.37-39
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• 1998

This paper presents the pressure-rise of the puffer cylinder in a model gas circuit breaker and the analyzed results of thermal interruption capability in SLF(short line fault) to the diameter of the puffer cylinder. This paper can be applied to the design of the EHV interrupter.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.349-350
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• 1999

Two of the factors to be considered at the design stage of the extinction chamber have been examined numerically. one is the sectional area of puffer cylinder, another is that of nozzle throat. the variation of the sectional area of puffer cylinder allowed us to find the size optimal at the interrupting performance. it is shown that the sizes of nozzle throat influenced the pressure rise of puffer cylinder strongly.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.12
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• pp.725-731
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• 2004

In this study, the three type hybrid interrupters according to the arrangement of the thermal expansion chamber and the puffer cylinder(they are called 'serial type', 'parallel/exchanged type', and 'parallel/separated type' respectively in this work) were designed and manufactured. This paper presents the tested results of the thermal recovery characteristics on the interrupters using a simplified synthetic test facility. The 'serial type' hybrid interrupter which is to obtain more easily the pressure rise for the thermal recovery compared with the others has the best capability in the thermal recovery characteristics. In order to investigate the stress on the operating mechanism, the distortion of the stroke wave in on-load test was examined to the stroke curve in no-load test. The biggest distortion was occurred in the 'parallel/exchanged type' hybrid interrupter. Finally, the small interruption capability on the three type interrupters was estimated by a theoretical form and the 'parallel/separated type' hybrid interrupter has the advantage of the others in the view of structure.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.9
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• pp.538-544
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• 2004

This paper presents the interruption capability of serial-hybrid type GCB (gas circuit breaker) compared with that of puffer type. First a puffer type model interrupter which has the stroke length of 80 mm has been designed and manufactured. And also, a serial-hybrid type interrupter which has the same design parameters as the puffer type interrupter except the serially arranged thermal-expansion chamber and puffer cylinder has been fabricated. Using a simplified synthetic test facility, the critical interruption capabilities of the two GCBs have been estimated. The critical di/dt, the critical dV/dt of ITRV (initial transient recovery voltage) and the minimum arcing time of the puffer type model GCB were 10.7 A/${\mu}\textrm{s}$, 5.5 kV/${\mu}\textrm{s}$, and 15.0 ms respectively. In the case of serial-hybrid type model GCB, each of the values was 16.6A/${\mu}\textrm{s}$, 11.5 kV/${\mu}\textrm{s}$ and 13.0 ms. As a conclusion of this work, it has been quantitatively confirmed that the hybrid type interrupter can obtain the sufficient interruption capability at the operating force which is so low that puffer type interrupter has not the interruption capability.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.7
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• pp.362-368
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• 2006

This paper presents the results of a small capacitive current interruption test for the three types of interrupter which are called 'serial type', 'parallel/separated type' and 'puffer type' according to the arrangement of the thermal expansion chamber and the puffer cylinder. After the preconditioning test the small current interruption capability of the 'puffer type' decreased, on the contrary, that of the hybrid interrupters increased. A number of reignition have been occurred in the 'serial type' hybrid interrupter and the change of small current interruption capability after preconditioning test is mainly influenced by the structure of interrupter. Finally it has been proved that the 'parallel/separated type' hybrid interrupter has the best interruption performance through the verification tests.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.737-738
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• 2002

To develop and improve a GIS(Gas Insulated Switchgear), the prediction of the pressure in puffer cylinder and the flow between the nozzle and the moving electrode within GIS is very important.The leading companies in GIS business issue the results of the study of flow within GIS including arc plasma. In this study, the characteristics of the flow of the GIS developed by HHI(Hyundai Heavy Industries Co. Ltd.) was investigated. To simulate the compressible flow of GIS, the CFX, a commercial CFD code, was used. With moving grid method, the movement of piston and electrode was simulated. The moving grid method was superior to the method of varying the property of cells to move an obsticle, in stability and convergencce of solution. The calculated maximum pressure within the puffer cylinder was matched with experimental data within $5{\%}$ error. The oscilation of pressure in GIS after the movement of electrode was well predicted.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.9
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• pp.408-413
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• 2005

This paper presents the basic design technology on the hybrid type GCB(gas circuit breakers) through the test results. The three type hybrid interrupters according to the arrangement of the thermal expansion chamber and the puffer cylinder(they are called 'serial type', ' parallel/exchanged type ,' and ' parallel/separated type ' respectively in this work) were designed and manufactured and then the tests of operating characteristics and interrupting were performed using a simplified synthetic test facility. The interruption capability with the type and the opening speed and the pressure rise which is required to interrupt were examined. The change of pressure rise with the number of interruption was given quantitatively and therefore the pressure rise can be predicted. Finally, it was shown that the interruption capability tends to increase with the increasing of opening speed in the puffer type; however, the hybrid type interrupter has a different interruption characteristic.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1344-1346
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• 1995

The interrupting capability of gas circuit breakers(GCB) are critically dependent on the pressure rise of the puffer cylinder or the thermal expansion chamber at current zero. Therefore it's very useful for the designers to know the pressure rise there at the design stage. Much effort has been done to predict the pressure rise in the puffer cylinder or the thermal expansion chamber in no-load condition. Thus, we now calculate it with reasonable accuracy with the simple programs coded by ourselves or with the commercial CFD packages. However, it has been still difficult problem to calculate it under the existence of arc. In this paper, we propose a method which can be used to predict the pressure rise in the thermal expansion chamber of thermal expansion type GCB. The method has been applied to the 25.8kV 25kA thermal expansion type model GCB and the calculated results have been compared with those from experiment.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.475-478
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• 1995

The variations of cold gas properties such as density, pressure, temperature and velocity which are dependent each other are closely related with the dielectric recovery of an interrupter. So, the pressure-rises at no-load in the puffer cylinder and in front of fixed arcing contact of 800kV model interrupter were measured experimentally using pressure transducers of strain gage type and semiconducting type, respectively. The maximum value of pressure-rise in the puffer cylinder increased almost linearly from 7.6 bar at the minimum operated pressure to 9.7 bar at the maximum operated pressure, while the pressure-rise in front of fixed arcing contact was independent with the operated pressure. The measured values will be utilized in verifying the self-developed cold flow analysis program and as an input of commercialized CFD program package.