• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 A
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• pp.374-376
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• 2001

FACTS technology is developed into the sophisticated system technology which combines conventional power system technology with power electronics, micro-process control, and information technology. Its objectives are achieving enhancement of the power system flexibility and maximum utilization of the power transfer capability through improvements of the system reliability, controllability, and efficiency[1]. As a series and shunt compensator, UPFC consists of two inverters with common dc link capacitor bank. It controls the magnitude of shunt bus voltage and real and reactive power flow of transmission line[2]. In this paper, we present the design and control algorithm of UPFC simulator for KERI simulator. As a control algorithm is implemented by digital controller, we consider sample-and-hold of signals In this simulation, we use EMTDC/PSCAD V3.0 software which can simulate instantaneous voltage and current.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 F
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• pp.2067-2069
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• 1998

A prototype semiconductor switch for the command resonant charging system has been developed for a line type modulator, which charges parallel pulse forming network(PFN) up to voltage of 5 kV at repetition rates of 60 Hz. A phase controlled power supply provides charging of the 4.7 ${\mu}s$ filter capacitor bank to voltage up to 5 kV. A solid state module of series stack array of sixe matched SCRs(1.6 kV, 50 A) is used as a command charging switch to initiate the resonant charging cycle. Both resistive and RC snubber network are used across each stage of the switch assembly in order to ensure proper voltage division during both steady state and transient condition. A master trigger signal is generated to trigger circuits which are transmitted through pulse transformer to each of the 6 series switch stages. A pulse transformer is required for high voltage trigger or power isolation. This paper will discuss trigger method, protection scheme, circuit simulation, and test result.

• 조명전기설비학회논문지
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• 제20권3호
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• pp.6-11
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• 2006

본 논문은 전력품질 향상을 목적으로 VSC의 새로운 제어 기법의 디자인에 대하여 기술하였다. 전압강하의 빠른 검출 기술은 동기 회전 d q-기준축에서 순시값의 검출을 통해서 구현되었다. 1차 디지털 필터는 노이즈에 대하여 둔감한 특성을 막을 수 있는 검출 알고리즘을 부가하였다. 필터의 전체 검출과 컷오프 주파수 사이에서 관계에 대하여 기술하였다. 에너지 저장 요소로서 사용되는 캐패시터 뱅크의 사이즈는 회로 해석으로서 입 출력 에너지의 관점에서 디자인 되었다. 마지막으로, 제안된 기법의 유효성은 모의실험을 통하여 증명되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.2113-2115
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• 2000

It is necessary to install the arc generation facility in order to obtain the important technology for the design of breakers and switches, and for the improvement of their performance and reliability. With this facility, it is possible, to study the characteristics of Arc in air/gas/vacuum insulation environment. The facility briefly consists of capacitor bank which can charge enormous energy, an air-core reactor, experimental arc-chamber, and several measurement equipments. This facility can simulates the arc phenomena in breakers and switches by means of generating high currents. In order to study the arc phenomena in SF6 gas and vacuum and to test the quenching performance of the extinguishing chambers which are developing. we made experimental $SF_6$gas/vacuum chambers and measured several parameter's of chambers. And besides we visualized arc ignition and arc movement by means of high speed camera.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 C
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• pp.1840-1842
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• 2003

This paper describes an experiment of detecting a temperature and components of arc plasma of electrical circuit breaker with a spectroscopic system. The system includes an optical fiber, a monochromator which has three gratings from low to high resolution and ICCD of which time resolution is 50 ns. This system enables measuring a temperature and components of arc plasma of a circuit breaker which is generated and extinguished in a few ms. We use a Planck's law and Boltzmann Plot method for calculating a temperature of arc plasma. A Xenon lamp is used for calibrating the system and this is very important for calculating a temperature of arc plasma. In this study, Arc plasma of Ag and Cu contact was investigated and these represent the contact of low voltage and extra-ultra high voltage circuit breaker, respectively. 8 $kA_{rms}$ test current was applied with a capacitor bank.

• Journal of Power Electronics
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• 제7권2호
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• pp.97-108
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• 2007

This paper describes simple control structures for a vector controlled stand-alone induction generator (IG) for use under variable speeds. Different control principles, indirect vector control and deadbeat current control, are developed for a voltage source PWM converter and the three-phase variable speed squirrel-cage IG to regulate DC-link and generator voltages with a newly designed phase locked loop circuit. The required reactive power for the variable speed IG is supplied by means of a PWM converter and a capacitor bank to buildup the voltage of the IG without the need for a battery, to reduce the rating of the PWM converter while using only three sensors and to eliminate the harmonics generated by the PWM converter. These proposed schemes can be used efficiently for variable speed wind energy conversion systems. The measurements of the IG systems at various speeds and loads are given and show that these systems are capable of good AC and DC voltage regulation.

• 한국정밀공학회지
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• 제7권2호
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• pp.14-27
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• 1990

Electromagnetic Pulse Forming is the one of the high velocity forming method. When the electric energy which is charged in the capacitor bank is suddenly discharged into the electromagnetic coil, the high magnetic field occurs at the airgap between the electromagnetic coil and workpiece. Thus we can obtain the high electromagnetic pressure, which is proportional to the square of magnetic flux density. This is the basic principle of the electromagnetic pulse forming. In this paper, the equivalent L-R-C circuit is derived by computing the magnetic field and its loss of the total system. Thus, the values of the magnetic flux density and pressure can be obtained from the equation of this circuit. As a result, the computed and measured values of the maximum magnetic flux density and pressure are compared and the characteristics of the tapered field shaper are further discussed as follows; 1) The strength of magnetic flux density and pressure can be controlled by the charged energy and the size of the airgap between the inner field shaper and the workpiece. 2) During the design of the tapered field shaper, the penetration of the magnetic flux through the sharp edge should be considered.

• 전자공학회논문지
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• 제54권8호
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• pp.107-114
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• 2017

본 논문에서는 3상 4선식 전력계통에서 새로운 전압제어 방식의 역률보상시스템을 제안한다. 제안하는 전압제어 방식의 역률보상시스템은 슬라이닥을 이용하여 가변되는 출력전압을 커패시터에 인가하는 것으로 보상에 필요한 무효전력을 생성한다. 기존의 커패시터 뱅크 방법을 이용하는 역률보상시스템은 선택 가능한 커패시터 용량이 한정되어 있어 부하 상황에 따라 역률보상 오차가 발생하지만, 제안 시스템은 변화하는 부하를 추종하여 오차 없이 역률을 100%까지 보상할 수 있다. 본 논문에서는 3상 4선식 전력계통에서 전압제어 방식의 역률보상시스템과 제어 알고리즘을 개발하였고 모의실험과 실험을 통해 성능을 확인한다. 제안 시스템을 수용가에 설치할 경우 역률 개선을 통한 전기료 감소, 선로손실 감소, 부하 용량 증대 효과가 기대된다. 특히 발전 사업가 측에서는 역률 보상 성능의 향상으로 송전 여유 용량 확보와 발전량 절감이 가능하다.

• 대한전자공학회논문지SD
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• 제43권9호
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• pp.17-22
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• 2006

본 논문에서는 IEEE 802.11a/b/g 무선 랜을 위하여 고속 AFC 기법이 적용된 CMOS LC VCO의 설계를 다룬다. 1.8V $0.18{\mu}m$ CMOS 공정을 사용하였으며, 현재 국제적으로 표준화가 진행된 모든 무선 랜 응용에 적합하도록 인덕터 및 캐패시터를 스위칭하는 방법으로 5.8GHz 대역, 5.2GHz 대역 및 2.4GHz 대역에서 동작하도록 설계하였다. 또한 주파수-전압 특성을 선형화하기 위하여 최적화된 버랙터 바이어싱 기법을 사용하였으며, 필요로 하는 모든 대역에서 저잡음 특성을 유지하기 위하여 4비트 캐패시터 뱅크를 사용하고, 광대역 디지털 주파수 검출기를 이용한 고속 AFC 기법을 구현하여 그 동작을 확인하였다.

• 전기학회논문지
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• 제67권7호
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• pp.809-815
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• 2018

Distributed generations (DGs) using renewable energy resources in power systems have been widely integrated, and many of these DGs have intermittency. DGs can significantly affect the overall voltage profile of the system through the reactive power control for a voltage support. Therefore, in the planning stage of the optimal operation and dispatch of voltage regulation devices, DGs' hosting capacity with the reactive power control scheme should be considered. In this paper, we model the IEEE 34-bus test feeder, including all essential equipment. An optimization method is utilized to determine the optimal siting and operation of the voltage regulation devices in the presence of DGs with reactive power control scheme. Finally, we compare the optimal results of the each case to analyze the relationship among the hosting capacity of the DGs and voltage regulation devices operation.