• Journal of Electrical Engineering and Technology
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• 제4권2호
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• pp.272-276
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• 2009

In this paper, the arc region of a gas circuit breaker (GCB) is analyzed using the fast moving least square reproducing kernel method (FMLSRKM) which can simultaneously calculate an approximated solution and its derivatives. For this problem, an axisymmetric and inhomogeneous formulation of the FMLSRKM is used and applied. The field distribution obtained by the FMLSRKM is compared to that of the finite element method. Then, a whole breaking period of a GCB is simulated, including analysis of the arc gas flow by finite volume fluid in the cell, and the electric field of the arc region using the FMLSRKM.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.516-517
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• 2011

마이크로그리드는 분산전원 또는 계통의 Sag/Swell 및 단락사고, 지락사고 등으로 인한 정전 발생 시에 사고 지점을 제외한 독립운전이 가능해야 한다. 따라서 사고 발생지점을 신속하게 분리할 수 있는 기술이 필요하다. 이러한 배경으로 본 연구에서는 신속하게 사고지점을 차단하는 고속차단 시스템(TCB :Thyristor Circuit Breaker)을 제안한다. 도통손실이 작고 경제적인 Thyristor를 이용하여 25 [kVA]급 TCB 시스템을 제작하고 사고를 모의하여 사고 발생 시의 TCB 시스템 동작특성에 대해 연구한다.

• 전기학회논문지P
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• 제60권3호
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• pp.133-137
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• 2011

The purpose of smart grid is the low $CO_2$ through expansion of renewable energy. To achieve the purpose of smart grid, typical radial power distribution system will be changed to loop power distribution system. The loop power distribution system have many advantages such as low power loss, low voltage drop, and increase of connection of renewable energy. In this paper, the algorithm for minimization of interrupted section of power distribution system is proposed through communication between circuit breaker and recloser in loop power distribution system. The proposed algorithm is proved through case studies about reliability evaluation

• 조명전기설비학회논문지
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• 제27권7호
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• pp.24-28
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• 2013

Fire-hited electrical equipment has possibility of deterioration. So its replacement is essential in terms of safety. However, the economic burden is increased. Therefore, the replacement or re-use of it is to be determined by tests. But the research of Integrity Assessment on Fire-hited electrical equipments is very rare. In this paper, we tested to determine the replacement or re-use of Fire-hited vacuum circuit breaker. And provided the data for the integrity assessment through the analysis of its deterioration.

• 대한전기학회논문지:전력기술부문A
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• 제53권1호
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• pp.31-37
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• 2004

In this paper, the analysis result of the switching surge in substation including GIS(Gas Insulated Switchgear) has been described using the EMTP(Electro Magnetic Transient Program) program. After performing the modeling of the input data, we have reviewed the energization overvoltages of GCB(Gas Circuit Breaker) without closing resistor in 345kV network, according to the conditions of simultaneously operating switch and statistically operating switch. Firstly, it can be known that the energization overvoltage of single line is higher than that of parallel energized line. Secondly, the maximum energization overvoltage obtained in statistics switch is higher than one in simultaneous switch. From these results, it can be known that the phase-to-earth energization overvoltages of $\alpha$-$\beta$ section are less than 2.2 p.u when closing resistor is eliminated. Therefore, it is possible to consider the circuit breaker eliminated the closing resistor in $\alpha$-$\beta$ section.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권2호
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• pp.76-82
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• 2005

In this paper, a method for analyzing the thermal recovery characteristics of the nozzle of gas circuit breaker was described. In order to obtain thermal recovery characteristics, the transient simulation of SF6 arc plasma within the nozzle was carried out. In particular, the nozzle ablation was taken into account by simultaneously solving the PTFE concentration equation with the governing equations such as continuity, momentum and energy equation. After that, post arc current calculation was performed with the rate of rise of recovery voltage changed. From the calculated post arc current, it was possible to suggest the thermal recovery characteristics of the nozzle of gas circuit breaker.

• Journal of Electrical Engineering and Technology
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• 제1권1호
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• pp.92-97
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• 2006

This paper presents the characteristic analysis and the optimal design of a permanent magnetic actuator (PMA) for a vacuum circuit breaker (VCB) using a two-dimensional finite element analysis. The purpose of this research about a PMA is to minimize the breaking time and the volume of the permanent magnet within the limits of the holding force and maximum current in the coil. The conjugate gradient method is used as an optimization algorithm. The node moving technique is iteratively implemented until the design variables of the PMA are optimized. In this paper, the optimal design of a PMA is accomplished to improve the conventional design methods.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.812-815
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• 1997

A dynamic model of air circuit breaker with a spring-actuated linkage is derived, and its validation for analysis and design, particularly appropriateness for an analysis of high-speed motion behavior are checked through experiments. The dynamic model is developed through the modeling process based on ADAMS and Pro/Engineer. The simulation results of derived dynamic models for the rapid closing and opening operations are compared with actual responses using a high-speed camera and investigated to validate their usefulness.

• 한국정밀공학회지
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• 제19권10호
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• pp.163-170
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• 2002

The dynamic model of a high-speed vacuum circuit breaker mechanism with spring-actuated cam and linkage is derived to simulate the high-speed closing and opening operations. Its validation for an analysis of high-speed motion behavior is checked through experiments. The characteristics of the friction on the camshaft are investigated using the nonlinear pendulum experiment. The parameters of the friction model are estimated using the optimization technique. The analysis exhibits that the friction of the pendulum depends on stick-slip, Stribeck effect and viscous damping. Comparing simulation results with actual responses using a high-speed camera, the appropriateness of derived dynamic models for the rapid closing and opening operations is shown. The spring motion, which has much influence on the closing responses, is observed.

• 한국전기전자재료학회논문지
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• 제29권5호
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• pp.307-311
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• 2016

Although there are existing Residual Current Protective Device (RCD) including detect electric leakage and elements such as short circuit and surge, the occurrence of incidents caused by electric faults, including fire, are still constant. The purpose of this study is to analyze the causes of accidents through the electric field distribution in the interpretation of the fault contact breaker. Simulation results by the arc fault has shown the convergence of temperature and electric field to the defect. Through their simulation results, the main cause of erosion phenomena in circuit breaker bar is the electric arc by concentration of electric field not due to dissolve by temperature.