• 디지털산업정보학회논문지
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• 제15권4호
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• pp.19-29
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• 2019

Recently, with the rise of environmental issues and the change of government policy (Renewable Energy 3020 Implementation Plan), a large amount of renewable energy such as solar and wind power is connected to the power system, and most of the renewable energy is concentrated in the power distribution network. This causes many problems with the voltage management and the protection coordination of the grid due to the its intermittent power generation. In order to effectively operate the distribution network, it is necessary to deploy more intelligent terminal devices in the field to measure the status of the distribution network and develop various operation functions such as visualization and big data analysis to support the power distribution system operators. In addition, the failover technology must be supported for the non-stop operation of the power distribution system. This paper proposes the system architecture of new power distribution management system to cope with high penetration of renewable energy. To verify the proposed system architecture, the functional unit test and performance measurement were performed.

• 한국전자통신학회논문지
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• 제9권6호
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• pp.641-647
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• 2014

독립형 태양광발전시스템은 배전선로와 계통 연계되지 않고 독립적으로 운영된다는 장점이 있어 시공설비가 간단하고 비용이 적게 드는 장점이 있지만 MPPT를 포함한 컨버터와 생산된 에너지를 배터리에 저장하기 위한 충전회로 및 배터리 매니징 회로가 요구된다. 기존의 대체에너지분야의 이용은 복합발전의 형태보다는 하나의 발전 형태를 주로 채택하고 있으나 태양광/풍력 복합발전시스템을 최적설계하고 배터리능력을 향상시켜 설치가격을 합리화 할 수 있는 통합형 제어시스템이 필요하다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.384-386
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• 2003

Striking in change that present our country is much by electricity industry reform and the Korea Electric Power Corporation is deciding power distribution system reliability indices every year but power distribution system for reliability evaluation and establishment of investment program are consisting punily. If consider efficient inflection of resources and hereafter power distribution division that is limited for target achievement of schedule level service evaluation and reliability side in operation of the power distribution system, can expect efficient practical use of the power distribution property if gains in electrical side about these change and most suitable investment way consist because there is necessity of electric power plan establishment of area electric power distribution place of business unit. This paper consider proper reliability level and maximum effect through quantitative analysis to gain electrical gains of the power distribution system in reliability side depending on trend DB(Data Base) of data of electric power system composition appliance in this treatise and apply data administration and reliability rate analysis that serve to decide most suitable investment precedence to supply of electric power property to power distribution system present investment algorithm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.399-402
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• 2003

In this paper, the on line volt/var control algorithms of the food Load Tap Changer (LTC) transformer and Shunt Capacitor(SC) are proposed for distribution volt/var regulation. In the existing volt/var control of the distribution substation, the voltage of feeders and var of distribution systems is mainly controlled by the LTC transformer tap position and on/off status of the shunt capacitor. The LTC and shunt capacitor bank has discrete operation characteristics and therefore it is very difficult to control volt/var at the distribution networks within the satisfactory levels. Also there is limitation of the operation times of the LTC and shunt capacitor bank because it is affects on their functional lifetime. The proposed volt/var control algorithm determine an optimal tap position of LTC and on/off status of shunt capacitors at a distribution network with the multiple feeders. The mathematical equations of the proposed method are introduced. Simple case study was performed to verify the effectiveness of the proposed method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.558-560
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• 2003

The effects of surge arresters for protection of transmission systems against direct lightning strokes have already been investigated using the digital simulation program EMTP. Distribution lines are spanned on a much large area as compared to transmission lines, and therefore, are more often susceptible to lightning strokes. This paper analyzes the overvoltages on underground cable system against direct lightning strokes to the overhead ground wire using the digital simulation. The effects of lightning protection methods, such as lowering the grounding resistance and installing the surge arrester, for preventing overvoltages on underground cable system caused by direct lightning strokes to the overhead ground wire is investigated. Several schemes have been proposed to protect underground cables. This paper summarizes the main results of a study aimed at analysis of lightning overvoltages in variety underground feeders protected by metal-oxide arresters. This study will provide insulation coordination methods for reasonable system design in 22.9kV underground cable system.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.300-300
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• 2008

우리나라의 전기에너지 수요가 지속적으로 증가함에 따라 새로운 송배전 선로의 구축이 필요하다. 하지만 현재 도심지의 전력구에는 더 이상의 지중선의 증설은 불가능하며 가공선 설치의 경우 환경 민원의 부담을 떠안게 된다. 그래서 기존 동도체의 회선당 송전 한계를 극복하고 대용량 송전 및 손실을 크게 줄일 수 있는 초전도 케이블의 연구가 세계적으로 활발히 진행되고 있다. 한국전력 전력연구원은 신 전력시스템으로서의 22.9 kV급 초전도케이블 시스템을 고창전력시험센터에 설치하고 운영 및 유지 보수 과정을 통하여 실제 계통 적용을 위한 최적 운전조건을 연구하고 있다. 이 논문에서는 실제 부하 상황을 모의하기 위하여 초전도케이블의 장기 부하변동 시험에 따른 케이블 송전 능력 확인 및 냉각시스템의 반응성을 살펴보고 부하변동 시험 후 초전도케이블 도체 열화 여부를 확인하기 위하여 직류 임계전류를 측정하였다. 그 결과 부하변동 시험 전의 임계전류 값과의 변화율이 삼상 모두 ${\pm}1$% 내외로서 오차범위를 벗어나지 않으므로 건전한 것으로 판단되었다.

• 전기학회논문지
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• 제59권2호
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• pp.298-305
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• 2010

In this paper, a new algorithm of optimal Volt/Var Control is proposed using Volt/Var control for the Distribution Automation System (DAS) with Distributed Generation (DG) based on the modeling of the distributed load and the distributed current. In the proposed, algorithm based on the modeling of the distributed load and the distributed current are estimated from constants of four terminals using the measurement of the current and power factor from a Feeder Remote Terminal Unit (FRTU) and DG data from RTU for DG. For the optimal Volt/Var Control, the gradient method is applied to find optimal solution for tap, capacity and power control of OLTC (On-Load Tap Changers), SVR (Step Voltage Regulator), PC (Power Condenser) and DG (Distributed Generation). In the case studies, the estimation and control of the voltages have been testified in a radial distribution system with DG using matlab program.

• 전기학회논문지
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• 제60권1호
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• pp.26-31
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• 2011

In this paper, we focused on the loop distribution system to solve the international issues of energy depletion and global warming. The conventional method of reconfiguration of distribution system was moving open points of switches from an actual switch position to another, while an appropriate switch must be opened to preserve the radial structure and this procedure is continued til there is no further loss reduction. However, the loop distribution system is the best optimization method to minimize loss than the other methods which is preserving radial structure. So we analyzed 3 types of loop distribution system upgraded from radial distribution system by changing normally open switch to normally closed switch. The simple 3 types of model system for simulation were composed, and each types of loop system were simulated in accordance with varying parameters. As a result of simulations, the loss reduction was different for each types of loop distribution system and each loop types have constraints for composing loop distribution system. The algorithms propose the method how to construct loop distribution system regarding constraints. Type I that needs least requirements get least loss reduction and Type III that needs most requirements get maximum loss reduction. On the other hand, Type I was most feasible distribution system to be realized.

• 전기학회논문지
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• 제60권1호
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• pp.20-25
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• 2011

This paper analyzed the application of Superconducting Fault Current Limiter (SFCL) on 22.9 [kV] bus tie in a power distribution system. Commonly, the parallel operations of power main transformers offer a lot of merits. However, when a fault occurs in the parallel operation of power main transformer, the fault currents might exceed the interruption capacity of existing protective devices. To resolve this problem, thus, the SFCL has been studied as the fascinating device. In case that, Particularly, the SFCL could be installed to parallel operation of various power main transformers in power distribution system of the Korea Electric Power Corporation (KEPCO) on 22.9 [kV] bus tie, the effect of the resistance of SFCL could reduce the increased fault currents and meet the interruption capacity of existing protective devices by them. Therefore, we analyzed the effect of application and proposed the proper impedance of the R-type SFCL on 22.9 [kV] bus tie in a power distribution system using PSCAD/EMTDC.

• 전기학회논문지
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• 제63권6호
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• pp.738-745
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• 2014

Recently, various measures have been discussed for overcoming depletion of fossil fuels and environmental pollution. One of the measures is electric vehicles. But electric vehicles has some limitations from high cost of battery and low efficiency, so operation distance of electric cars is limited. Also there are difficulties that charging lines should be connected by an electric car whenever it charges. Thus, many studies have been conducted to overcome the limitation using conventional batteries of electric vehicles. As a result, the OLEV(On-Line Electric Vehicle) was developed. But the OLEV system is some limitations. The OLEV system causes power quality problems when it charges. Power quality problem cannot be ignored because OLEV systems are closely connected by distribution grids. In this paper, the OLEV system is designed by using PSCAD/EMTDC, and the power quality is measured and evaluated. Power quality is divided by two cases; harmonics and high-frequency. Harmonics were evaluated according to IEEE Std. 519-1992. But the evaluation of High-frequency could not take it because there was no standard. For this reason, the data measured by OLEV system was compared with the EN50065 regulation.