• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.12
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• pp.80-86
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• 2012

The high-voltage pulse generator is consist of transformers of fundamental wave and harmonic waves, and shunt capacitances. The pulse has the fundamental wave and the harmonic waves that have been increased as a series circuit by the transformers to make high voltage pulse. This paper shows the high-voltage pulse generator simulation using a circuit program with experiment data. In the equivalent circuit, magnetized inductances and loss resistances which affect output voltage, have been obtained. The output capacitor circuits have characteristics of band pass. The output voltages of the pulse width 50% and 25%(PWM) were obtained. The output of the high-voltage pulse generator is 2.5kHz, 1.8kV.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.147-149
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• 2000

This paper describes a power flow method for distribution systems, applying the method of symmetrical component to back/forward sweep method. The proposed algorithm is effective for unbalanced radial distribution system, with process of distributed resource(PQ & PV node), AVR(Auto Voltage Regulator), shunt capacitor. This proposed method compared conventional back/forward sweep method with the using three phase unbalanced distribution systems with 34 nodes.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.181-182
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• 2006

GPS(Global Positioning System)을 기반으로 한 PMU(Phasor measurement Unit) 장치는 계통의 여러 가지 동특성 정보를 내포하고 있는 페이저 정보를 제공한다. 이러한 PMU 정보를 이용하여 계통의 전압 안정도를 판단, 감시하여 보다 신뢰성이 높게 계통을 안정적으로 운영을 할 수 있고, 계통보호를 위한 Shunt Capacitor 투입 시 적절한 시기와 양을 결정할 수 있도록 도와준다. 본 논문에서는 기존의 저전압 계전기를 이용한 저전압 현상과 실시간 지역정보를 이용한 전압 안정도 지수를 함께 고려함으로써 보다 신속하고 신뢰성 높은 계통 보호방안을 모색하고, 이를 실시간 디지털 시뮬레이터인 HYPERSIM을 활용하여 순시치 환경에서 모의하였다.

• Proceedings of the KIEE Conference
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• summer
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• pp.224-226
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• 2004

Flexible AC Transmission System (FACTS) can greatly reinforce power systems through improvement of power transmission capacity and utilization of equipment under the circumstance of continuous load growth and deregulation SVC and STATCOM are shunt FACT devices that have similar static characteristics with Mwhuical Swikhed Capacitor (MSC). The main issue of this paper is the analysis of different dynamic characteristics when STATCOM is solely adopted and when STATCOM is adopted with combination of other reactive power compensator such as SVC and M5C. Furthermore, better application of reactive power compensators can be clarified through analysis of dynamic characteristics of various combinations of reactive power compensators.

• Proceedings of the KIEE Conference
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• 2004.07e
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• pp.27-29
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• 2004

This paper presents improved teaching and learning Gill for easily analysis tool of load flow of power system. This GUI includes not only contingency analysis function, but also calculating power loss from transmission line flow. The Gill is friendly for study for power system operation and control because picture provide a better visualizing of relationships between input parameters and effect than a tabula type result. This Gill enables topology and the output data of load flow for line outages to be shown on same picture page. Users can input the system data for power flow on the the picture and can easily see the the result diagram of bus voltage, bus power, line flow. It is also observe the effects of different types of variation of tap, shunt capacitor, loads level, line outages. Proposed Gill has been studied on the Ward-Hale 6-Bus system.

• Journal of electromagnetic engineering and science
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• v.13 no.3
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• pp.189-191
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• 2013

This letter presents a compact metamaterial-based tunable zeroth-order resonant antenna. It is based on the double-negative unit cell with a function of tunable inductance realized by a varactor and impedance convertor in the shunt branch. The resonant frequency of the designed antenna ranges from 2.31 to 3.08 GHz, depending on the capacitance of the used varactor. Its size is very compact ($0.05{\lambda}_0{\times}0.2{\lambda}_0$) with a relatively wide tunable range of 29.1%. The impedance bandwidth of the antenna is from 20 to 50 MHz for the resonant center frequency. The measured maximum total realized gain is from -0.68 dBi (2.43 GHz) to 1.69 dBi (2.97 GHz). The EM-simulated and measured results are in good agreement.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.167-168
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• 2008

이 논문은 변전소 환경에서 LTC, S.C, FACTS 간의 협조제어를 통한 전압 profile 개선을 논한다. 변전소 자체 내의 전압-무효전력 제어기기인 LTC, S.C 이외에도 현재에는 더 나은 전력전송과 전압안정을 위해 FACTS를 설치하는 경우가 늘고 있기 때문에 위의 3가지기기에 대한 협조제어 알고리즘에 대한 필요성은 점차 증대된다고 할 수 있다. 이러한 3가지 기기들의 협조제어를 통해서 전압 profile 개선에 관하여 연구하였으며 그러한 연구들은 Hypersim(real-time simulator) 기반에서 수행하였다.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.401-403
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• 2001

This paper describes a power flow method for distribution systems, applying the method of symmetrical component to back/forward sweep method. The proposed algorithm is effective for unbalanced radial distribution system, with process of AVR(Auto Voltage Regulator), shunt capacitor. The proposed method was compared with the conventional Back/forward sweep method by using three phase unbalanced distribution systems of 123 nodes.

• Journal of Power Electronics
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• v.11 no.6
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• pp.931-937
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• 2011

This paper presents a method for the performance improvement of a shunt active power filter (SAPF) using the indirect current control (ICC) scheme. Compared to the conventional direct current control (DCC) scheme, the ICC gives better performance with a lower number of sensors. A simplified and efficient control algorithm using a low cost Intel 80C196KC microcontroller is implemented using only two current sensors for the source current and one voltage sensor for the DC-link voltage of the SAPF circuit. The objective is to eliminate harmonics and to compensate the reactive power produced by non-linear loads such as an uncontrolled rectifier feeding an inductive load. The APF is realized using a three phase voltage source inverter (VSI) with a dc bus capacitor. Experimental results are presented to prove the better performance of the ICC method over the DCC one.

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.571-573
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• 1995

This paper presents a method for optimal dispatch which minimizes transmission losses and improves voltage profile of power systems using genetic algorithm based on the mechanism of natural genetics and natural selection. The constraints are VAR sources(transformer tap, generator voltage magnitude and shunt capacitor/reactor), load bus voltages and generator reactive power. Real variable-based genetic algorithms which can save coding times and maintain the accuracy are applied for optimal dispatch of reactive power. The genes of genetic algorithm consisted of integers for considering discrete VAR sources. A efficient operator for crossover is proposed to consider the effect of close genes. The algorithm proposed can apply to problems for large scale power systems with multi-variables and complex nonlinear functions efficiently. The proposed method is applied to IEEE 30 buses model system to show its effectiveness.