• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 A
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• pp.289-291
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• 2001

This paper represents the application of the Static Var Compensator (SVC) on the electric railway power supply system to compensate for the voltage drop. The high reactance of line and a heavy train load consume a significant amount of the reactive power which results the voltage drop. This paper shows that the SVC is necessary for voltage compensation in the railway power supply system and verify effectiveness of the SVC through the simulation by using PSCAD/EMTDC. In this paper, the case studies were performed with the various line length and train loads.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 F
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• pp.2054-2056
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• 1998

A conventional UPS can supply the clean power to the load. However, it may generate input current harmonics and the input power factor can be very poor. Therefore, the UPS itself may be a power interruption. This paper provides multifunctional converter of using single phase UPS. The proposed UPS can supply the clean power to the load without polluting the mains power system. The multi-functional converter provides battery charging, var compensation and harmonic suppression simultaneously. It was simulated to verify this work.

• 조명전기설비학회논문지
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• 제25권6호
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• pp.82-89
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• 2011

Reactive power support is considered to be necessary for dealing with a voltage stability issue with wind turbine system employing squirrel-cage induction generator(SCIG). This paper analyses steady-state characteristics of the SCIG wind turbine system by simulating torque-slip characteristics of SCIG with respect to variations of interconnecting network strength and generator terminal voltage. It also presents dynamics analysis of SCIG wind turbine system on Simulink to investigate the impact of static var compensator(SVC) and static synchronous compensator(STATCOM) on transient stability enhancement. It analysed transient stability with varying fault duration times and compared the transient stability characteristics with varying rated capacities of SVC and STATCOM. It is shown that the STATCOM has a better performance and reactive power support compared to SVC.

• 전력전자학회논문지
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• 제20권3호
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• pp.290-295
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• 2015

Analysis and verification of reactive power compensator (RPC) for ITER pulsed power electric network (PPEN) are described in this paper. The RPC system is rated for a nominal power of 250 Mvar necessary to comply with the allowable reactive power limit value from the grid 200 Mvar. This system is currently under construction and is based on static var compensation technology with a thyristor-controlled reactor and a harmonic filter. The RPC minimizes reactive power from grid using prediction of reactive power consumption of AC-DC converters. The feasibility of the reactive power compensation was verified by assembling a real controller and implementing ITER PPEN in the real time digital simulator for the hardware-in-loop facility. When maximum reactive power is reached, grid voltage is stabilized and maximum reactive power decreased from 120 Mvar to 40 Mvar via the reactive power prediction method.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1997년도 전력전자학술대회 논문집
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• pp.299-302
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• 1997

This paper describes a dynamic var compensator to compensate the line reactance for power transmission and distribution system. The compensator consists of a voltage source inverter with dc capacitor, coupling transformers, and control circuit. The operation of compensator was verified by computer simulations with EMPT and experimental works with a scaled hardware model. The advantage of the proposed system is rapid and continuous regulation of the reactive power.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.304-305
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• 2015

본 논문에서는 국내 기존 제련 공장의 무효전력을 보상하기 위한 SVC(Static Var Compensator)의 구성과 제어기에 대하여 소개하고자 한다. 본 SVC는 제련 공장의 22.9kV 계통에 적용하는 보상장치로써 TCR(Thyristor controlled reactor), Air-core Reactor, 2,3,4,5차 고조파 필터, 제어반 등으로 구성된다. 이는 Hybrid SVC을 적용한 사례이다. 역율 제어와 전압 제어를 적용하여 전력 품질 확보를 기하고자 설계 되어졌으며 SVC의 용량 ${\pm}100MVar$가 적용되어졌다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2015년도 전력전자학술대회 논문집
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• pp.423-424
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• 2015

전압 안정도를 향상 시키고 무효전력을 보상하는 방법 중 하나로 정지형 무효전력보상설비(SVC, Static Var Compensator)를 사용한다. 특히, 전기로(EAF, Electric Arc Furnace) 등 비선형 부하가 주를 이루는 철강 민수 사업자의 부하는 단시간 내에 전류 변화가 급격히 일어나며 큰 전압 변동을 일으키므로 무효전력 보상설비를 적용하여 안정적인 전력을 공급하고 전력 품질을 확보해야 할 필요가 있다. 본 논문에서는 LS-Nikko 동제련 온산 공장에 역률 보상을 목적으로 무효전력을 제어하기 위한 ${\pm}100[MVar]$ SVC 시스템 모델을 소개하고, 그 특성에 대한 이해를 돕고자 한다.

• 한국산림과학회지
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• 제95권5호
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• pp.614-620
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• 2006

To study the chlorophyll contents and photosynthetic characteristics of 4 tree species of deciduous hardwoods; Betula platyphylla var. japonica, Zelkova serrata, Acer mono and Prunus sargentii were treated in 3 stages of shading; the full sun treatment, the medium shade treatment with 30% of transmittance comparing to full sun, the intense shade treatment with 8% of transmittance and their changes in chlorophyll contents and photosynthetic characteristics were examined and analyzed. Most hardwoods showed differences in the total chlorophyll contents in the order of May < September < July, however, that in Prunus sargentii increased progressively along with the lapse of time. Concerning the degree of shading, total chlorophyll contents increased in proportion to the level of shading. Betula platyphylla var. japonica and Prunus sargentii showed more than 2-3 times difference between the full sun treatment and the intense shade treatment. The changes in photosynthetic characteristics, the range of the light saturation point of the trees was $1,000{\sim}1,100{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ in May, before the shading was applied, and the intensity was shown in the order of Betula platyphylla var. japonica > Zelkova serrata > Acer mono > Prunus sargentii. The photosynthetic rate was $6.4{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}{\sim}27.1{\mu}mol{\cdot}CO_2{\cdot}m^{-2}{\cdot}s^{-1}$ in the order of Betula platyphylla var. japonica > Prunus sargentii > Acer mono > Zelkova serrata that there were differences between species. Concerning the changes in light saturation point in each growth period after shading treatment, the light saturation point in the full sun treatment was found in the range of $560{\sim}1,100{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ and the level of intensity was shown in the order of May > July > September. The light saturation point decreased as the level of shading intensified and the level of changes in light compensation point in the full sun treatment for Betula platyphylla var. japonica and Prunus sargentii was shown in the range of $2.9{\sim}27.1{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ in the order of May > July > September, however, for Zelkova serrata and Acer mono was shown in the range of $3.9{\sim}11.7{\mu}mol{\cdot}CO_2{\cdot}m^{-2}{\cdot}s^{-1}$ in the order of July > May > September that there were differences between species.

• 한국산림과학회지
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• 제107권3호
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• pp.316-323
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• 2018

본 연구는 고사리, 곰취, 산마늘 등 주요 산채류에 대한 재배공정을 조사하여 소득분석을 실시함으로써 향후 임산물에 대한 손실보상 기준 및 임업경영진단 등에 필요한 기초자료를 제공하기 위하여 실시하였다. 조사결과 품목별 재배형태는 크게 노지재배와 산지재배로 구분되었다. 품목별 단위면적당($3.3m^2$) 연간 평균소득은 고사리 노지재배는 6.5천원, 고사리 산지재배는 3.2천원, 곰취 노지재배는 20.4천원, 산마늘 노지재배는 20.9천원, 산마늘 산지재배는 7.3천원 등으로 나타났다. 특히, 최근 소비자 수요가 크게 증가하고 있는 산마늘과 곰취의 노지재배 단위면적당($3.3m^2$) 연간 평균소득은 고사리에 비해서 매우 높은 것으로 분석되었다. 이러한 원인은 고사리 재배 시 경영비(토지임차료, 고용노동비)의 투입비중이 타 품목에 비해 매우 높기 때문이다. 연간 평균소득이 높은 곰취와 산마늘의 경우 종묘 및 종근 구입 등 초기 투자비용이 경영비의 평균 40% 이상을 차지하고 있어 향후 농산촌지역의 소득원 및 재배 활성화를 위해서는 이에 대한 정부의 적절한 지원이 필요할 것으로 판단된다.

• Journal of Electrical Engineering and Technology
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• 제5권1호
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• pp.116-128
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• 2010

Modeling of the three phase electric arc furnace and its voltage flicker mitigation are the purposes of this paper. For modeling of the electric arc furnace, at first, the arc is modeled by using current-voltage characteristic of a real arc. Then, the arc random characteristic has been taken into account by modulating the ac voltage via a band limited white noise. The electric arc furnace compensation with static VAr compensator, Thyristor Controlled Reactor combined with a Fixed Capacitor bank (TCR/FC), is discussed for closed loop control of the compensator. Instantaneous flicker sensation curves, before and after accomplishing compensation, are measured based on IEC standard. A new method for controlling TCR/FC compensator is proposed. This method is based on applying a predictive approach with closed loop control of the TCR/FC. In this method, by using the previous samples of the load reactive power, the future values of the load reactive power are predicted in order to consider the time delay in the compensator control. Also, in closed loop control, two different approaches are considered. The former is based on voltage regulation at the point of common coupling (PCC) and the later is based on enhancement of power factor at PCC. Finally, in order to show the effectiveness of the proposed methodology, the simulation results are provided.