• 대한전기학회논문지:전력기술부문A
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• 제51권2호
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• pp.93-101
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• 2002

This paper describes a new method for determining the permissible operating range of DG(Distributed Generation) when DG is introduced into power distribution systems of which the voltage is controlled by LDC(Line Drop Compensator). Much of the DG installed during the next millennium will be accomplished through the reconstruction of the electric power industry. But in that case, it is difficult to properly maintain the terminal voltage of low voltage customers by using only LDC. This paper presents a method for determining the permissible operating range of DG for proper voltage regulation of power distribution systems with LDC. Proposed method has been applied to a 22.9 kV model and practical distribution systems, and its result is almost identical with the simulation result.

• 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.

• 전기학회논문지
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• 제63권2호
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• pp.224-229
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• 2014

This paper presents the novel voltage control method in power distribution system with distributed generators. The voltage in distribution systems is regulated by Under Load Tap Changer(ULTC) of substation and pole transformer of primary feeders. Recently, Step Voltage Regulator(SVR) is getting located at distribution feeders to regulate effectively voltage of primary feeders. But the effectiveness of SVR decreases due to independent operation between SVR and ULTC, and also the existing Line Drop Compensator(LDC) method considering the distributed generators may be not able to regulate the proper voltage in a permissible range. Thus, this paper presents a optimal voltage control algorithm of SVR by using the secondary voltage data of main transformer in substation.

• 조명전기설비학회논문지
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• 제16권5호
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• pp.53-60
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• 2002

본 논문에서는 정전류 부하모델 교류 전기철도 AT 급전시스템을 회로망 해석법(Loop Equation Method)을 이용하여 실제 급전시스템과 유사하게 제약조건을 두고 여러 경우를 가정하여 모델링 하였다. 이 방법을 통해 앞으로 건설될 고속 전기철도 급전시스템의 전력품질에 영향을 줄 수 있는 전압강하에 주안점을 두고 정상급전의 경우뿐만 아니라 연장급전의 경우를 새롭게 확대 해석하였으며 이 결과를 동적 시뮬레이션 프로그램인 PSCAD /EMTDC를 이용하여 그 정확성과 실용성을 검증하였다. 또한 사례연구를 통해 전압 보상기를 설치하지 않는 경우와 STATCOM을 설치한 경우의 전압강하 보상효과를 PSCAD/EMTDC로 시뮬레이션 하여 검증하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(2)
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• pp.896-899
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• 2003

The electric railway has been widely used as a transportation all over the world. It also was opened in 1973 in korea and it has been steadily proceeded in making electric railway network for a big city and building Keongbu high speed , electric railway. That's why the system of electric railway is able to solve the environmental pollution and operate the useful energy in environmental ways, it helps to increase the ability of transportation and to decrease the cost. Because of the advantage of making the economic situation better, the system of electric railway is trying to do their best in developing technique of electric railway. Because of the increasing of transportation and the high speed operation, cars with regenerative braking system was adapted. Therefore, unbalanced voltage and current of three phase system and the drop and rise of voltage of feeding circuit is expected. Now that building the substation, newly spends lots of costs and time, it is a very difficult situation to solve the problem. We can guess that electric railway line can't receive power from the power system of bigger size in building newly electric railway. In this paper, it was proved that series voltage compensator was suitable as a solution according to voltage drop and voltage fluctuating through computer simulation.

• 대한전기학회논문지:전력기술부문A
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• 제48권6호
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• pp.699-703
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• 1999

It is known that the LDC(Line-Drop Compensator) becomes to lose the function of proper voltage regulation for its load currents due to the real and reactive power generated by DGS(Dispersed Generation System), when DGS is introduced into the power distribution system of which the voltage is controlled by LDC. Therefore, in that case, it is very difficult to regulate the distribution line voltage properly by using LDC. One possible solution for this problem is the real-time voltage regulation method which is to optimally regulate the sending-end voltage in real-time by collecting the real-time load data of each load data of each load section between measuring points and by calculating the optimal seding-end voltage value from them. For this, we must know the real-time load data of each load section. In this paper, a modeling method of representing a load section on high voltage line with DGSs as an equivalent lumped load is proposed for gaining the real-time load data. In addition a method of locating the measuring points is proposed. Then, these proposed methods are evaluated through computer simulations.

• 조명전기설비학회논문지
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• 제23권2호
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• pp.53-61
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• 2009

현재의 배전계통의 전압은 변전소에서 단방향 조류를 고려하여 LCD에 의한 전압조정방법으로 ULTC 변압기의 탭을 변환하여 공급전압을 적정범위 내에서 유지되도록 운전하고 있다. 그러나 현재의 배전계통 운용은 소용량에서 대규모 용량에 이르기까지 다양한 용량의 PV 시스템이 배전계통에 연계되어 운전되는 것을 반영하지 못하고 있는 실정이다. 때문에 다수의 PV 시스템이 계통에 연계되어 양방향 조류가 발생하고 이로 인해 연계점의 전압변동이 발생하여도 이를 효과적으로 조정하지 못하여 계통의 전압이 적정범위 내에서 운용되지 못하는 경우가 발생할 수 있다. 따라서 본 논문에서는 다수 PV 시스템의 연계에 따른 양방향 조류의 발생을 고려하고 연계점의 전압변동에 따른 계통의 전압을 효과적으로 제어할 수 있도록 실시간 감시가 이루어지는 PV 시스템의 특징을 이용하고 기존의 LDC 전압조정방법을 개선하여 PV 시스템 연계 시에도 변전소에서 계통의 전압을 적정범위 내에서 조정할 수 있는 개선된 전압조정방법을 제안하였다.

• 전자공학회논문지 IE
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• 제43권1호
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• pp.32-38
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• 2006

유도전동기는 기동 시 전류가 정격전류의 6$\sim$8배에 이르기 때문에 경 부하로 운전하는 경우에는 역률을 떨어뜨릴 뿐만 아니라 과다한 기동전류로 인해 계통전원에 순간전압 강하를 유발시켜 선로의 전력품질저하가 심각하게 대두되고 있다. 본 논문에서는 PSCAD/EMTDC 패키지를 이용하여 IEEE에서 제시한 배전 계통 13버스 모형 모델 및 유도기 부하를 모델링 하여 사고모의 및 DSTATCOM의 보상효과를 시뮬레이션을 통하여 보였다.

• 대한전기학회논문지:전력기술부문A
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• 제48권6호
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• pp.692-698
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• 1999

This paper analyzes the effect of DGS(Dispersed Generation System) on the voltage regulation of the traditional distribution system of which the voltage is controlled by the bank LDC(Line Drop Compensator). Through the simulation results for 22.9kV class distribution system with DGSs, some general relationships among the operating power factor and introduction limit of DGS, and the sending-end reference voltage determined by internal setting coefficients of the LDC are derived. Those relationships are that the introduction limit of DGS increases as the power factor of DGS goes from lagging to leading and also as the allowance of the sending-end reference voltage increases. From the relationships, a operation method of the power distribution system integrated with DGSs is proposed from the view point of the operating power factor of DGS and new voltage regulation method.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 춘계학술대회 논문집
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• pp.241-244
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• 2008

Recently, the concern of PV systems has increased because of an environmental problem and limitation of fossil fuel. In this paper, we assume and simulate the cases that the voltage of distribution system exceed the bound of voltage regulation because of the connected PV system. Also, we compare the typical method, LDC(Line Drop Compensator), with the suggested method and verify propriety of suggested method.