• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.11a
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• pp.522-525
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• 2011

3상 4선식 배선 라인에서 중성선이 탈락할 경우 부하측의 중선선에 연결된 일부의 부하측 전압은 급상승하게 되고 이로 인한 피해가 많으므로 본 연구에서는 배전라인의 점검시 또는 접촉 불량에 의하여 발생할 수 있는 중성선의 탈락을 순간 감지하고 이를 보상하여 별도로 중성선을 생성하여 새로운 중성선을 순간 제공함으로서 중성선 탈락에 의한 피해를 최대한 억제하고자 하는 것이다. 이로 인하여 부하측의 전압상승에 의한 전기적 재해를 사전에 미리 예방이 가능한 효과도 있게 된다.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.1
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• pp.15-22
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• 2001

In this paper, a VSC(Voltage Sag Corrector) is discussed for the purpose of power quality enhancement. A fast detecting technique of voltage sag is accomplished through the detection of instantaneous value on synchronous reference frame. A robust characteristic against the noise is available by inserting the first order low pass filter in the detection circuit. The formula and the filter design process is described properly with the mathematical equations. Because the VSC system supply the active power to load, it is required to design the proper size of the energy storage system, In this paper, the capacitor bank is used as an energy storage system, and the size of the capacitor is designed from the point of view of input/output energy as the output power rating and the amplitude and duration time of the voltage sag. The simulation is accomplished by PSCAD/EMTDC.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.289-291
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• 2001

This paper represents the application of the Static Var Compensator (SVC) on the electric railway power supply system to compensate for the voltage drop. The high reactance of line and a heavy train load consume a significant amount of the reactive power which results the voltage drop. This paper shows that the SVC is necessary for voltage compensation in the railway power supply system and verify effectiveness of the SVC through the simulation by using PSCAD/EMTDC. In this paper, the case studies were performed with the various line length and train loads.

• Proceedings of the KIEE Conference
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• 1997.07c
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• pp.1097-1099
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• 1997

The implementation of Static Var Compensator(SVC) provides opportunites to maintain voltage profile and improve voltage stability in large scale power system. Under Load Tap Changing(ULTC) transformer has been used to control the voltage. It is necessary that Coordinated control of SVC and ULTC for the better performance. This paper shows that the characteristic of Voltage control using SVC or ULTC and the condition of the coordinated control considering dynamic voltage stability.

• Journal of the Optical Society of Korea
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• v.9 no.1
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• pp.6-12
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• 2005

The perturbation approach is applied to solve the nonlinear Schrodinger equation, and its valid range has been determined by comparing with the results of the split-step Fourier method over a wide range of parameter values. With γ= 2㎞/sup -1/mW/sup -1/, the critical distance for the first order perturbation approach is estimated to be(equation omitted). The critical distance, Z/sub c/, is defined as the distance at which the normalized square deviation compared to the split-step Fourier method reaches 10/sup -3/. Including the second order perturbation will increase Z/sub c/ more than a factor of two, but the increased computation load makes the perturbation approach less attractive. In addition, it is shown mathematically that the perturbation approach is equivalent to the Volterra series approach, which can be used to design a nonlinear equalizer (or compensator). Finally, the perturbation approach is applied to obtain the sinusoidal response of the fiber, and its range of validity has been studied.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.4
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• pp.523-528
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• 2015

A new algorithm for a coordinative control method is proposed with respect to voltage control and system stabilization of local substations. This is accomplished using control cooperation between a static synchronous compensator (STATCOM) and the existing voltage compensation equipment in the steady state and emergency state of a power system. A real-time system analysis was developed by combining a system analysis program with InTouch, which has primarily been used in factory automation for verification. PSS/E was used for the load flow calculation software, Python for language, Intouch as an HMI program, and MS SQL for the database. To test this system, the system in the vicinity of the Migeum and the Migeum substations was modeled and simulated.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.11
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• pp.1947-1954
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• 2007

This paper describes the development of a high-performance single-phase line-interactive Dynamic voltage Restorer, which is composed of an H-bridge inverter and super-capacitors. The operational feasibility was verified through computer simulations with PSCAD/EMTDC software, and experimental works with 3kVA prototype. The developed system can compensates the input voltage sag and interruption within 2ms, in which the maximum allowable duration of voltage interruption is 1.5 seconds. It can be effectively used to compensate the voltage interruption in the sensitive load, such as computer, communication equipment, automation equipment, and medical equipment. The developed system has a simple structure to be easily implemented with commercially available components and to be highly reliable in operation.

• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.1
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• pp.41-47
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• 2012

This paper proposes a calculation of compensation current using phase shift to eliminate ripple components of instantaneous active power under unbalanced or non-linear loads condition. The proposed phase shift method instead of existing method(LPF; Low Pass Filter) to remove ripple components and this proposed method improves performances of transient and steady state response. To compare proposed method with existing method, experiments have been done for calculating an average active power at load side. Their results show that transient response and steady state response of proposed method is improved.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.237-240
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• 2003

유도전동기는 기동시 전류가 정격전류의 6배$\sim$8배에 이르기 때문에 경부하로 운전하는 경우에는 역률을 떨어뜨릴뿐만 아니라 과다한 기동전류로 인해 계통전원에 순간전압 강하를 유발시켜 선로의 전력품질(Power Quality) 저하가 심각하게 대두되고 있다. 본 논문에서는 PSCAD/EMTDC 패키지를 이용하여 IEEE에서 제시한 배전 계통 13버스 모형 모델 및 유도기 부하를 모델링하여 사고모의 및 DSTATCOM의 보상 효과를 시뮬레이션을 통하여 보였다.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.29B no.3
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• pp.25-34
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• 1992

This paper proposes a Self-Tuning control algorithm for tracking the reference trajectory by measuring the end-point of robot manipulator whose links are light and flexible, and the performance of it is tested through the computer simulation. As an object of system, a flexible robot manipulator with two-links is considered and an assumed mode shape method including gravity force is adopted to analyze the vibration modes for each links and dynamics equation is derived. The controller is designed as a combined form which consists of dynamic feedforward compensator and self-tuning feedback controller. The one supplies nominal torque and the other supplies variational torque to manipulator. Apart from the, K-incremental predictor is also proposed in order to eliminate the offset error. and it shows that the result of simulation adapted well to load change and rapid velocity.