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

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2008년도 하계학술대회 논문집
• /
• pp.69-71
• /
• 2008

Recently, the interest on power quality has been hot issue because the equipments cause voltage disturbance and become more sensitive to the voltage disturbance. The DVR(Dynamic Voltage Restorer) is one of the Custom Power Device that can compensate the voltage. DVR operates as a series connected compensator whose output voltage can be controlled system voltage. And the magnitude of compensation voltage is limited by the characteristics of system and load. Compensation capability of DVR was simulated by EMTDC under several condition. This paper analyzed effect of DVR's compensation at power quality test center which has SSFG(Sag, swell, and Flicker Generator, CPDs(SSTS, DVR, DSTATCOM), and loads.

• 조명전기설비학회논문지
• /
• 제17권6호
• /
• pp.95-104
• /
• 2003

전기 철도계통은 기존 전력계통과 달리 단상, 대용량 부하로 필연적으로 전압강하, 전압불평형 및 고조파 왜곡 등의 전력품질의 문제가 발생한다. 이러한 문제점 중 상시전압강하는 전력품질의 가중 중요한 요소로서 SVC(Static Var Compensator) 또는 STACOM(Static Compensator)를 설치하여 전압강하를 보상하는 연구가 수행되었다. 또한 순시전압강하는 고속으로 운전중인 철도차량의 제어 및 안전에 상당한 영향을 미칠것으로 예상된다. 따라서 본 논문에서는 AT(Auto Transformer)급전계통에 적용되는 순간전압강하 보상장치에 관한 연구를 수행하였다. 순간전압강하에 의한 철도차량의 과도해석을 위해 전원, 철도급전변압기, AT, 철도선로 및 철도 차량부하를 모델링 하였다. 또한 순간전압강하 발생시 철도차량부하의 과도특성을 분석하였고 이를 보상하기위한 순간전압강하 보상장치 (DVR:Dynamic Voltage Restorer)를 제안하였다. 순간전압강하 보상 시뮬레이션 결과, 순간전압강하 보상장치의 철도급전계통의 적용은 상당히 유용함을 알수있었다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2002년도 하계학술대회 논문집 B
• /
• pp.1081-1083
• /
• 2002

Voltage sag is discussed a important problem of power quality in transmission sys-tem. So recently The study on the compensatio-n for voltage sag is made good progress, Especially a compensation in unbalance sources system is difficult. In this paper, we proposed a series voltage compensator and a rejection of voltage ripple from synchronous frame in unbal-anced sources

• Journal of Power Electronics
• /
• 제4권3호
• /
• pp.180-187
• /
• 2004

This paper proposes a new control strategy for the dynamic voltage restorer (DVR). It is based on a synchronous PI decoupling control strategy which features fast response time and low steady state error. Therefore, the proposed control strategy produces faster action time against voltage sag and guarantees more than enough compensation for reduced supply voltage. Experimental results, implemented with the TMS320C3${\times}$DSP control unit, are shown to validate the effectiveness of the proposed control strategy.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2007년도 학술대회 논문집 전문대학교육위원
• /
• pp.108-111
• /
• 2007

A novel voltage sag compensator with hi-directional DC/DC converter of Electric double layer capacitor is proposed. Recently, the double-layer capacitor which is drawn attention as a new energy storage element has a lot of advantage such as no maintenance, long lifetime and quick charge/discharge characteristics with large current. This DC/DC converter is used to control the charging current to the double-layer capacitor and also used to keep the DC link voltage constant for discharge of the double-layer capacitor. Therefore, the proposed DC/DC converter has the high-efficiency controller, dynamic compensator of voltage sag is driven by this converter. Finally, experimental results show the validity of the control scheme and the ability of the dynamic voltage compensator.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2008년도 하계학술대회 논문집
• /
• pp.458-461
• /
• 2008

This paper deals with a single-phase impedance-source dynamic voltage restorer (Impedance-DVR) to mitigate voltage sag/swell for the critical loads. The proposed system is composed of passive filter and impedance-source topology inverter. As an ESS(Energy Storage System) of the proposed system is employed the Proton Exchange Membrane Fuel Cells (PEMFC). To calculate and control the compensation voltage, single-phase $^id-^iq$ theory in dq rotating reference frame and PI controller are used. Simulation results under voltage sag and swell are presented to show the performance.

• Journal of Electrical Engineering and Technology
• /
• 제11권6호
• /
• pp.1645-1655
• /
• 2016

A Dynamic Voltage Restorer (DVR) model is proposed to eliminate the short-term voltage disturbances that occur in the grid-connected mode, the switching between grid-connected mode and the stand-alone mode of a Microgrid. The proposed DVR structure is based on a conventional cascaded H-bridge multilevel inverter (MLI) topology; a novel composite control strategy is presented, which could ensure the compensation ability of voltage sag by the DVR. Moreover, the compensation to specified order of harmonic is added to implement effects that zero-steady error compensation to harmonic voltage in specified order of the presented control strategy; utilizing wind turbines-batteries units as DC energy storage components in the Microgrid, the operation cost of the DVR is reduced. When the Microgrid operates under stand-alone mode, the DVR can operate on microsource mode, which could ease the power supply from the main grid (distribution network) and consequently be favorable for energy saving and emission reduction. Simulation results validate the robustness and effective of the proposed DVR system.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
• /
• 제5B권4호
• /
• pp.374-381
• /
• 2005

The ability to provide quality power has become a significant issue in power systems. The main causes of poor power quality are harmonic currents, poor power factor, supply-voltage variations, etc. A technique of achieving both active current distortion compensation, power factor correction and also mitigating the supply-voltage variation (sag or swell) at the load side is presented in this paper. The operation and rating issues of the proposed Single-phase Unified Power Quality Conditioner are also highlighted. To reduce the total cost while simultaneously increasing the performance, the system is fully digitally controlled using the fixed-point TMS320F240 digital signal processor. The performances of the UPQC, which is composed by shunt and series PWM controlled-converters, have been verified on a laboratory prototype.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 하계학술대회 논문집 A
• /
• pp.283-286
• /
• 2003

The electric traction load is quite differ from general power system load which is single-phase, high-speed heavy load receiving power from 3-phase power system and also has variable load characteristics over time and space. Therefore, there are inevitably power quality problems such as steady state or transient voltage drop, voltage imbalance and harmonic distortion. In addition, it is expected that transient voltage sag could affect the safety of feeding system. Thus, in this paper transient analysis and voltage sag compensation of AT(Auto Transformer) feeding system are studied. The fault study of traction network is analysed by using PSCAD/SMTDC simulation tool. In addition, application of DVR in electric traction system is proposed to compensate the voltage sag of traction network which is occurred by the fault of utility source. The results of fault study will be a useful research works for operation and setting of electric traction relay. Also, it can be shown that application of the DVR in electric system is very useful to compensate the voltage sag from the result of related simulated work. The results of study will be a useful research works for management and planning of power quality in electric traction system.