• Journal of Power Electronics
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• 제9권3호
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• pp.365-376
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• 2009

In this paper, the implementation of a three-phase shunt active power filter is presented. The filter is essentially three independent single-phase current-controlled voltage source inverters (CC-VSI) with a common DC bus. The CC- VSI is operated to directly control the AC grid current to be sinusoidal and in phase with the grid voltage without detecting the load currents. The APF consists of a current control loop, which shapes the grid currents to be sinusoidal and a voltage control loop, which regulates the active power balance of the system. The experimental results indicate that the active filter is able to handle predominantly the harmonics, as well as the unbalance and reactive power, so that the grid currents are sinusoidal, in phase with the grid voltages and symmetrical.

• Journal of Power Electronics
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• 제9권3호
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• pp.386-395
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• 2009

In this paper, a new control algorithm for the dynamic voltage restorer (DVR) is proposed to regulate the load terminal voltage during various power quality problems that include sag, swell, harmonics and unbalance in the voltage at the point of common coupling (PCC). The proposed control strategy is an Adaline (Adaptive linear element) Artificial Neural Network (ANN) and is used to control a capacitor supported DVR for power quality improvement. A capacitor supported DVR does not need any active power during steady state because the voltage injected is in quadrature with the feeder current. The control of the DVR is implemented through derived reference load terminal voltages. The proposed control strategy is validated through extensive simulation studies using the MATLAB software with its Simulink and SimPower System (SPS) toolboxes. The DVR is found suitable to support its dc bus voltage through the control under various disturbances.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.285-288
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• 2000

This paper presents a technique for contingency ranting using line capacity calculation method and outage distribution factors(LODF) which are established by generation shift distribution factors from DC load flow solutions. By using the LODF, the line flow can be calculated a ccording to the modification of base load flow if the contingency occur. To obtain contingency ranting, maximum power tansferred to the load is obtained when load impedance $Z_r$ equal to line impedance $Z_s$. ( $Z_r$/ $Z_s$=1) The proposed algorithm has been validated in tests on a 6-bus test system.

• Journal of Power Electronics
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• 제10권1호
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• pp.91-96
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• 2010

In this paper, a simplified control algorithm for a three-phase, four-wire unified power quality conditioner (UPQC) is presented to compensate for supply voltage distortions/unbalance, supply current harmonics, the supply neutral current, the reactive power and the load unbalance as well as to maintain zero voltage regulation (ZVR) at the point of common coupling (PCC). The UPQC is realized by the integration of series and shunt active filters (AFs) sharing a common dc bus capacitor. The shunt AF is realized using a three-phase, four leg voltage source inverter (VSI) and the series AF is realized using a three-phase, three leg VSI. A dynamic model of the UPQC is developed in the MATLAB/SIMULINK environment and the simulation results demonstrating the power quality improvement in the system are presented for different supply and load conditions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 학술대회 논문집 전문대학교육위원
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• pp.95-98
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• 2000

This paper presents a technique for contingency ranking using line capacity calculation method and outage distribution factors (LODF) which are established by generation shift distribution factors from DC load flow solutions. By using the LODF, the line flow can be calculated a ccording to the modification of base load flow if the contingency occur. To obtain contingency ranking, maximum power tansferred to the load is obtained when load impedance $Z_r$ equal to line impedance $Z_s$. The proposed algorithm has been validated in tests on a 6-bus test system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 F
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• pp.2798-2800
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• 1999

A new circuit, modified valley fill (MVF) combined with resonant inductor of the self-excited resonant inverter and charge pump capacitors(CPCs), is presented to achieve high PF electronic ballast providing sufficient preheat current to lamp filaments for soft start maintaining low DC bus voltage. The MVF can adjust the valley voltage higher than half the peak line voltage. The CPCs draw the current from the input line to make up the current waveform during the valley interval. The measured PF and THD are 0.99 and 12%, respectively. The lamp current CF is also acceptable in the proposed circuit. The proposed circuit is suitable for implementing cost-effective electronic ballast.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.57.3-57
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• 2001

This paper introduces a system which offers the possibility to access remote CAN devices over the Internet as if they were local. The system consists of a local computer and the DSP server. The DSP is connected to a CAN bus with a DC motor and to a Internet simultaneously. The DSP board consists of a LAN controller and a CAN controller. It can convert to a protocol between CAN and Internet. The DSP board is not based on a personal computer. This board is profited a small and light system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.538-539
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• 2008

전력 산업은 대규모 투자가 필수적인 산업이라 자연 독점으로 남아 있게 되는 경우가 다반사이다. 그래서 사용 요금은 시장의 규칙에 의해서가 아니라 규제자에 의해 많은 부수적인 방법을 통해 회수하고 있다. 본 논문에서는 모선 간 전력량을 고려한 전력망 사용요금 산정법을 제안하고자 한다. Equivalent Bilateral Exchange(EBE)와 Relative Electrical Path Width(REPW)를 각각 정의한 후 EBE와 REPW를 이용하여 전력 이동량을 계산하고 모선 간 전력 이동량을 바탕으로 DC 조류 계산을 이용하여 전력망 사용량을 할당하는 방법을 제안하였다. 제안된 방법을 검증하기 위해 2기 4모선을 테스트 시스템으로 선정해 기존의 방법과 비교를 해 보았다.

• 대한전기학회논문지:전력기술부문A
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• 제49권7호
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• pp.323-331
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• 2000

Recently Advanced Static Var Compensators(ASVC) or STATic Synchronous COMpesator(STATCOM) has been considered as a next generation reactive power controller. The STATCOM is a voltage source inverter(VSI) based on the static VAr compensator with only small capacitors on the dc side. The main function of the STATCOM is to keep the bus voltage magnitude at the desired value. This paper compared the PAM STATCOM with the PWM STATCOM. The characteristics and the control method of each model is analyzed. And the simulation of STATCOMs based on the above two methods is presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 C
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• pp.1044-1047
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• 1999

This paper deals with the dynamic property of ground overvoltage relay in large turbine generator. Relay operation is based on detecting the fundamental voltages originating from the generator. Calculations of fault voltage and current are reviewed for the neutral ground resistance. The frequency, ampitude and waveform of individual harmonics were measured using power quality analyzer and memory hi-corder at the secondary side of ground potential transformer. The ac and dc high-potential tests were applied to evaluate the condition of generator, main and auxiliary transformer, isolated phase bus, potential transformer, surge capacitor and arrester.