• The Transactions of the Korean Institute of Electrical Engineers
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• v.32 no.3
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• pp.76-83
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• 1983

This paper describes the method of operating the phase controlled rectifier by controlling the firing angle in III, IV quadrant to absorb the lrading reactive power and of improving the waveform of ac current by driving dual converter. The system is intended to compensate the reactive power for any lagging load. Also, by the above method this paper enables us to improve the power factor and waveform referred to the source current and the dc output voltage in the converter.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.1103-1106
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• 2002

This paper presents SVC which use PAM method and eliminate harmonics. Inverter is connected directly so that SVC improve output voltage waveform into 24 steps. Inverter output waveform THD is reduced to 6.89%. Leading control of reactive power generated in power system is possible. Snubber is added to reduce switching loss.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2481-2483
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• 1999

This paper proposed the p-q-r coordinate system where the instantaneous active power p, and the two instantaneous reactive powers $q_{q}$, $q_{r}$ were defined. The three power components are linearly independent, so the compensation for the two instantaneous reactive powers leads to control the two components of the current space vector. With the theory, the neutral current of a three-phase four-wire system can be eliminated by only compensating the instantaneous reactive power using no energy storage element.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.688-692
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• 1988

The active filter system for harmonic current compensation is presented in this paper. The active filter, composed of a three-phase voltage-type PWM inverter and the capacitor, compensates both the harmonic currents and the reactive power by injecting the PWM current to the ac line. This paper describes the principle of harmonic current compensation, the calculation circuits for the harmonic currents to be injected, the several compensation characteristics. Also the experimental results are shown to verify the theory proposed in this paper.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.11
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• pp.1183-1190
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• 1990

In this paper, instantaneous reactive power compensation algorithm is proposed and analyzed. The static Var generator developed in this paper is the current source PWM converter using hysteresis comparator method, which compensates the reactive power by detecting each instantaneous phase voltage and line current, independently. Some aspects on the static Var compensator-such as inductance, capacitance, hysteresis width, and switching frequency, etc.-are discussed. The dynamic performances are examined through digital simulation and experimental test.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.6
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• pp.869-876
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• 1994

This paper presents an efficient method to calculate voltage collapse point and to avoid voltage instability. To evaluate voltage stability in power systems, it is necessary to get critical loading points. For this purpose, this paper uses linear programming to calculate efficiently voltage collapse point. Also, if index value becomes larger than given threshold value, voltage stability is improved by compensation of reactive power at selected bus. This algorithm is verified by simulation on the IEEE 14-bus sample system.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.767-769
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• 1993

A multilevel PWM voltage source inverter, especially five-level one, is introduced to obtain a static var compensator(SVC) as a large scale power, source. In this paper, the three phase SVC is modeled using circuit DQ transformation and completely analyzed. Finally, through the experimental results from 5-kVA SVC, the validity of the analyses and the feasibility of the SVC system are shown for high power applications.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.131-133
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• 1998

This paper, proposed the p-q-r coordinate system where the instantaneous active power p, and the two instantaneous reactive powers $q_{q}$, $q_{r}$ were defined. The three power components are linearly independent, so the compensation for the two instantaneous reactive powers leads to control the two components of the current space vector. With the theory, the neutral current of the three-phase four-wire system can be eliminated by only compensating the instantaneous reactive power using no energy storage element.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.442-443
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• 2006

본 논문에서는 현재 전류원 HVDC로 연계되어있는 제주-해남 전력계통을 전압원 HVDC로 대체하였을 경우 동특성을 분석한 내용에 대해 기술하고 있다. 동적특성분석을 위해 EMTDC를 이용한 시뮬레이션모델을 개발하고 전압원 HVDC가 일정조류제어와 주파수제어를 수행할 때 유무효전력의 제어특성을 분석하였다. 전압원 HVDC 시스템은 전류원 HVDC와는 달리 컨버터 자체로 유무효전력을 독립적으로 제어할 수 있어 동기조상기와 캐패시터뱅크 같은 무효전력보상설비를 필요로 하지 않는다. 본 연구결과는 향후 전압원 HVDC 시스템의 설치를 검토할 때 활용 가능할 것으로 보인다.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.478-479
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• 2018

본 논문에서는 무정전 CTTS 시스템에 적합한 영전력 투입과 영전류 차단이 가능한 알고리즘을 제안한다. 제안된 알고리즘은 이종전원에 크기와 위상차를 고정도로 검출하기 위해 이종전원의 차를 검출하였고 이를 통해 CTTS 투입 시 돌입전류를 감소시킬 수 있었다. 또한 순시 유무효전력 제어로 CTTS 차단 시 UPS 출력전류를 영전류로 제어하여 무아크 및 계통 안정화를 이룰 수 있었다. 또한 본 시스템은 UPS 동작뿐만 아니라 무효전력 보상기인 조상기로 사용 가능하며 특히 계통 전압안정화용으로 사용가능함을 확인하였다.