• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.1
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• pp.18-23
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• 1991

Recently SLAMECKA suggested the mathematical dynamic arc model of the SF6 gas circuit breaker [1]. The author applied the above dynamic arc model to the E.H.V. transmission line and investigated the interrupting capability of the SF6 gas circuit breaker. In particular the Runge-Kutta-England numerical method suitable for the use in systems that involve nonlinear dynamic arc and traveling wave was used by converting the current source into the voltage source in the DOMMEL's method [2]. The successful computer resultls were obtained and it was found that the arc time constant and the second derivative of the arc conductance are closely related to the interrupting capability of the SF6 gas circuit breaker.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.204-210
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• 1997

The paper deals with the design and evaluation of a new static-exciter for generator excitation systems to improve the steady-state and transient stabilities. It increases or maintains the generator field current by boosting the field voltage in the case of an input AC line voltage drop during and immediately after a fault. The validity of the proposed excitation system is verified with computer simulation. The simulation results of the stability analysis on the generator with the proposed exciter is better than that of a conventional static exciter and a conventional AC exciter. Also, this proposed exciter can be simply implemented and controlled by modern power electronics technology.

• Journal of the Korean Society of Groundwater Environment
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• v.6 no.1
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• pp.1-7
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• 1999

This study deals with linear flow pattern in steady-state or transient dual-porosity media with a vertical geologic structure such as fault, fracture zone, etc. A pumping well is located in the vertical structure of infinitesimal or finite width with high hydraulic conductivity and negligible specific storage. Selected type curves on a pumping well and observation wells in the fractured system and the matrix block are provided. The type curves on the pumping well considers both wellhole and well-loss effects.

• Journal of Energy Engineering
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• v.13 no.1
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• pp.68-74
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• 2004

This paper presents the design of DSTATCOM (Distribution Static Synchronous Compensator) controller. The results are verified by using PSCAD/EMTDC package. The state equation derived by decomposition analysis of DSTATCOM current component is applied to load model and the combined model which considered constraint condition. In case of single line to ground fault, the conventional method of Pl control is compared with LQR control technique. LQR control is shown to be superior in terms of response profile and composition of voltage sag.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.1 no.1
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• pp.65-74
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• 1995

There is no line of demarcation between the shoulder and elbow regions. Pain In the arm may originate at the shoulder with reference downwards or less often at the elbow with reference upwards. Most pains indicated by the patient at the elbow or forearm have a local origin, since at the more distal part of the upper limb the capacity for correct localization is good. Once it is clear that the elbow region is at fault, the joint and the muscles about it are tested by ten movements. 1. Four. Passive extension, flexion, pronation, supination-full range, LOM, painful, painless. 2. Four. Resisted extension, flexion, pronation, supination-strong, weak, painful, painless. 3. Two. Resisted flexion, extension at the wrist-painful, painless. The muscles that perform theses two movements arise from the humeral epicondyles and a lesion in either often causes pain felt at the elbow although the tissuse affected is not functionally a part of the elbow (i. e. Tennis elbow and Golfer's elbow).

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.971-972
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• 2011

초전도 저항형 한류기는 계통에서 발생하는 대규모의 사고 전류를 매우 빠른 시간 안에 효과적으로 제한할 수 있어 주목받고 있는 초전도 전력기기이다. 저항형 한류기를 제작할 때 사용되는 초전도 선재의 총 길이는 저항형 한류기의 전체 설계에 있어서 가장 핵심적인 변수중 하나로 기존의 허용전기장을 이용한 방법으로 도출될 수 있다. 하지만 기존의 방법에서는 계통의 라인 저항을 고려하지 않는 가정을 도입 했기 때문에 이를 이용하여 설계할 경우 실제로 시스템에서 요구하는 설계 변수와 큰 차이를 보일 수 있다. 본 논문에서는 라인저항의 영향을 고려한 허용 전기장을 도출하고, 새로 계산된 선재의 길이와 기존의 방법을 이용하여 계산된 선재의 길이를 비교해 봄으로써 보다 정확한 설계의 가능성을 제시한다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.320-321
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• 2011

As the scale of industries expands, the facilities of the industrial customer become larger and more complex. When a fault occurs in the system, the circuit breakers play an important role in minimizing causalitites by quickly tripping the faulted line. Since the capacity of the receiving-end has increased in size, an examination is needed to be performed between the industrial customers and the conventional circuit breakers. The transient recovery voltage, which is the initial transient characteristics of the voltage across the breaker when tripped, is an important factor in determining the circuit breaker's performance. In this paper, a TRV analysis on the large-scale industrial customer is being performed utilizing PSCAD/EMTDC.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.376-377
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• 2011

DTS(Dispatcher Training Simulator)는 EMS(Energy management System) 전력계통 모델을 기반으로 off-line 환경에서 운영되는 급전원 훈련용 시뮬레이터이다. 급전원들은 DTS를 활용하여 다양한 상황별 시나리오를 반복 훈련함으로써 실제 전력계통 운영 및 유사시 대응능력을 배양할 수 있다. 본 논문은 전력거래소 중앙급전소에서 급전원 훈련용으로 사용되는 DTS의 다양한 기능 및 구조, 활용실적과 실시간 계통운영 적용 사례를 소개하고자 한다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.3
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• pp.506-514
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• 2010

Defense systems are needed to prevent catastrophic failures of a power grid due to cascaded events. Cascaded events can be occurred by power flow overload. Especially, it is the most dangerous problem that overload line is outage, because it can make the power system face danger of cascaded. In this paper, vulnerability evaluation for monitoring wide are outage is proposed using by configuration information of transmission systems. This method of vulnerability evaluation is considered direct effect and indirect effect of power flow, especially overload. What is more, it can be used when the configuration of power system changes, as simple fault occurs or maintenance of facility. In the case studies, the estimation and simulation network have been testified and analysed in PSSE and C programming.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.4
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• pp.718-724
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• 2009

Recently, Increase of energy consumption is continued accordingly because economy is constant growth. so we need long term of energy supply stability and develop new energy source. The effort of environmental improvement is necessary and our country has to educe conservatory gas in these situation, our energy policy is summarized that minimizes energy consumption and uses kinds of energy source. This paper studied some effort of stability that distributed generation put in electric system through line fault, sudden load change. And then this paper calculated penetrated level of distributed generation in system transient stability.