신경회로망을 이용한 UPFC가 연계된 송전선로의 거리계전기에 관한 연구

이준경,박정호,이승혁,김진오,Lee, Jun-Kyong,Park, Jeong-Ho,Lee, Seung-Hyuk,Kim, Jin-O 한국조명전기설비학회 2004 조명·전기설비학회논문지 Vol.18 No.6

전력계통분야의 복합 대형화에 유연한 대처와 전력조류의 최적화 도모를 위해 사용되는 FACTS(Flexible AC Transmission System)기기 중 가장 유용한 UPFC(Unified Power Flow Controller)는 선로의 전압을 임의의 크기와 위상을 갖도록 제어하여 선로로 전송되는 유ㆍ무효전력을 총체적으로 보상하는 기능을 갖는다. 이런 UPEC가 계통에 연계되어 운영된다면 송전선로 매개변수가 변하기 때문에 계통의 영향을 많이 받는 거리계전기는 불필요한 오동작이 발생하게 된다. 즉 거리계전기에서 바라본 임피던스 영역(Impedance Zone)이 송전선로에 UPFC 연계시 각각의 보상 값에 의해 상당한 변화를 보임으로, 기존의 방식으로 정정된 Relay Setting Zone과 Adaptive Setting Zone은 현저한 오차가 발생하게 된다. 그러므로 계통에 연계된 UPFC의 운전 조건을 고려한 거리계전기 보호구간의 재설정이 필요하게 된다. 따라서 본 논문의 목적은 학습이 가능한 신경회로망(ANN)을 이용하여 거리계전기 동작의 신속성(Speed)을 기본으로 전력계통의 다양한 환경에 대해 거리계전기 응동 특성을 향상시키는데 있다. 학습 방법으로는 정적 및 동적인 비선형 시스템의 인식과 다변수 시스템에 적용 가능한 역전파 알고리즘(Back-propagation Algorithm)을 사용했다. This paper represents a new approach for the protective relay of power transmission lines using a Artificial Neural Network(ANN). A different fault m transmission lines need to be detected classified and located accurately and cleared as fast as possible. However, The protection range of the distance relay is always designed on the basis of fixed settings, and unfortunately these approach do not have the ability to adapt dynamically to the system operating condition. ANN is suitable for the adaptive relaying and the detection of complex faults. The backpropagation algerian based multi-layer protection is utilized for the teaming process. It allows to make control to various protection functions. As expected, the simulation result demonstrate that this approach is useful and satisfactory.

전동차 사무소의 전압불평형 보상을 위한 SVC 적용에 관한 연구

이준경,이승혁,김진오,Lee, Jun-Kyong,Lee, Seung-Hyuk,Kim, Jin-O 한국조명전기설비학회 2004 조명·전기설비학회논문지 Vol.18 No.3

본 논문에서는 전동차 사무소에서 FACTS 설비 중 전기철도시스템에 일반적으로 많이 사용되고 있는 SVC 적용에 대해 검토하였다. 전기철도 급전계통 중 전동차 사무소의 비상용 철도부하와 일반부하에 따른 전압변동, 전압강하, 전압불평형의 보상에 관해 SVC(Static Var Compensator)의 적용이 적절한 가에 대한 검토에 대한 연구가 필요하다. 이에 따라 SVC 도입 검토를 위해 이미 적용된 설계사양을 기본으로 PSCAD/EMTDC 시뮬레이션을 이용하여 전동차 사무소에 SVC를 적용하였을 경우 전압변동, 전압강하 및 전압불평형 각 항목의 결과를 도출하고, 이를 SVC 제작사의 성능시험과 비교하였다. AC electric railroad system receives its power from 3-phase transmission system. Since trainloads are moving continuously, the voltages for the single load fluctuate in the train garage, and moreover, the fluctuating voltages generate high-order harmonics. This means the difficulty in maintaining power quality in the power system. Therefore, in this paper, the adequacy of SVC application is investigated for the train garage in KNR(Korean National Railroad). Voltage drop, voltage regulation, and unbalanced voltages are assessed in the train garage for the condition of power system both with svc and without SVC. In this paper, PSCAD/EMTDC is used for the above assessment items, and the results are compared with ones which was already designed in the field in practice for the train garage. As a result, the train garage using SVC improves power quality.

인천 국제공항청사 경전철 도입에 따른 고조파 영향 분석

이준경(Jun-Kyong Lee),이승혁(Seung-Hyuk Lee),김진오(Jin-O Kim),정현수(Hyun-Soo Jung) 대한전기학회 2005 대한전기학회 학술대회 논문집 Vol.2005 No.7

STATCOM을 이용한 고속전철 부하가 연계된 계통의 안정도 향상에 관한 연구

李埈敬(Jun-Kyong Lee),吳栽炅(Jae-Kyoung Oh),金鎭吾(Jin-O Kim) 대한전기학회 2003 전기학회논문지A Vol.52 No.11

인천 국제공항청사 경전철 도입에 따른 고조파 영향 분석

이준경(Lee Jun-Kyong),이승혁(Lee Seung-Hyuk),김진오(Kim Jin-O),정현수(Jung Hyun-Soo) 한국철도학회 2005 한국철도학회 학술발표대회논문집 Vol.- No.-

This paper presents harmonic evaluation of an IAT(Intra Airport Transit) system in Incheon International Airport. It will be used electric vehicles with 80 kW per car that are produced Mitsubishi Heavy Industries Ltd, and one car is constructed with SIV(Static Inverter), VVVF(Variable Voltage and Variable Frequency) and two induction motor. The operated vehicles in the IAT system are rapidly changing DC load, and at a feeding substation, 3-phase electric power is transferred to DC 750 V by rectifier. Since, vehicles are also changing continuously, the voltages for the DC load fluctuate in the IAT system, and moreover, the fluctuating voltages generate high-order harmonics. This means that there is the difficulty in maintaining power quality in KEPCO systems" side. Therefore, the power quality of the IAT system in Incheon International Airport is evaluated using PSCAD/EMTDC simulator in the paper. The THD(Total Harmonic Distortion) of voltages and TDD(Total Demand Distortion) of currents, indices are calculated for the IAT system using the results of PSCAD/EMTDC dynamic simulation.

모멘트 정합 방법(Moments Matching Method)을 이용한 전기철도 급전시스템의 고조파 평가

李埈敬(Jun-Kyong Lee),李丞爀(Seung-Hyuk Lee),金鎭吾(Jin-O Kim) 대한전기학회 2007 전기학회논문지 Vol.56 No.1

Generally, an electric railroad feeding system has many problems due to the different characteristics in contrast with a load of general three-phase AC electric power system. One of them is harmonics problem caused by the switching device existing in the feeding system, and moreover, the time-varying dynamic loads of rail way is inherently another cause to increase this harmonics problem. In Korea power systems, the electric railroad feeding system is directly supplied from the substation of KEPCO. Therefore, if voltages fluctuation or unbalanced voltages are created by the voltage and current distortion or voltage drop during operation, it affects directly the source of supply. The trainloads of electric railway system have non-periodic but iterative harmonic characteristics as operating condition, because the electric characteristic of the electric railroad feeding system is changed by physical conditions of the each trainload. According to the traditional study, the estimation of harmonics has been performed by deterministic way using the steady state data at the specific time. This method is easy to analyze harmonics, but it has limits in some cases which needs an assessment of dynamic load and reliability. Therefore, this paper proposes the probabilistic estimation method, moments matching method(MMM) in order to overcome the drawback of deterministic method. In this paper, distributions for each harmonics are convolved to obtain the moments and cumulants of TDD(Total Demand Distortion), and this can be generalized for any number of trains. For the case study, the electric railway system of IAT(Intra Airport Transit) in Incheon International Airport is modeled using PSCAD/EMTDC dynamic simulator. The raw data of harmonics for the momets matching method is acquired from simulation of the IAT model.

전동차 사무소의 SVC 적용에 따른 고조파 발생에 관한 연구

이승혁,이준경,김진오,Lee, Seung-Hyuk,Lee, Jun-Kyong,Kim, Jin-O 한국조명전기설비학회 2004 조명·전기설비학회논문지 Vol.18 No.3

교류 전기철도 시스템은 3상 전원으로부터 전력을 수전 받지만, 철도부하는 단상이므로 열차가 운행될 경우 3상 전원 측에 전압불평형을 유발시키게 된다. 전기철도 시스템 중 전동차 사무소의 경우도 일반 3상부하와 비상용 철도 부하가 운영되므로 전압불평형 및 전압강하 현상이 발생하게 된다. 이러한 전압불평형이나 전압강하는 고조파 발생의 주원인이 되고, 고조파는 전동차 사무소의 정밀한 기기들의 오동작을 초래할 수 있다. 따라서, 전동차 사무소의 이러한 문제를 해결하기 위하여 본 논문에서는 SVC의 사용을 제안하였다. 또한 SVC를 이용하여 전동차 사무소의 전압불평형 및 전압강하를 보상할 경우 발생할 수 있는 고조파에 대해 PSCAD/EMTDC를 이용하여 분석하였다. 결과적으로, 전동차 사무소의 전압강하 및 전압불평형 보상을 위한 SVC는 전력품질을 향상시킨다는 것을 본 노문에서 확인하였다. AC electric railroad system receives its power from 3-phase transmission system, Since, trainloads are changing continuously, the voltages for the single-phase load fluctuate in the train garage, and moreover, the fluctuating voltages generate high-order harmonics. This means that there is the difficulty in maintaining power quality in the power system. Therefore, a Static Var Compensator(SVC), which in general compensates the reactive power, is used in order to balance the trainload. In this paper, PSCAD/EMTDC is used for the analysis of harmonic generation in the train garage using SVC. The Total Harmonic Distortion(THD) of voltages is calculated using PSCAD/EMTDC dynamic simulation. As a result, the train garage using SVC improves power quality.

Quasi-renewal 이론을 이용한 발전설비의 불완전한 유지보수 예방정비 계획

金亨埈(Hyung-Jun Kim),卞隆泰(Yoong-Tae Byun),金鎭吾(Jin-O Kim),李埈敬(Jun-Kyong Lee) 대한전기학회 2008 전기학회논문지 Vol.57 No.5

Recently, the research of PM (Preventive Maintenance) method on the RCM(Reliability-Centered Maintenance) of the system equipment is being actively advanced for a few years. For the most of the current power equipment maintenance, the state of the equipment after maintenance is assumed to be becoming 'as good as new ones' state. However, the state of the power equipment is maintained like the states of the between 'as good as new ones' and 'as bad as old ones' by imperfect maintenance that implies the life decrease of the equipment by frequent breakdown, the error of maintenance process, and so on. So, the Maintenance method considering the real case has to reflect Imperfect maintenance than perfect maintenance. This paper suggests the Preventive Maintenance method by using Quasi - Renewal Theory for the gas turbine equipment as deliberating the imperfect maintenance for the real cases.

철도급전시스템의 고조파 평가를 위한 확률론적 방법

李丞爀(Seung-Hyuk Lee),宋學宣(Hak-Seon Song),李埈敬(Jun-Kyong Lee),金鎭吾(Jin-O Kim) 대한전기학회 2006 전기학회논문지A Vol.55 No.9

The harmonic currents generated along with the operating speed of electrical railroad traction are very difficult to analyze because of its nonlinear characteristics. This paper therefore presents probabilistic approach for the evaluation of harmonic currents about the operating speed of the arbitrary single traction. To use probabilistic method for railroad system, PDF (Probability Density Function) using measuring data based on the realistic harmonic currents per operating speed is calculated. Measuring data of harmonic current per operating speed is obtained using the result data of PSCAD/EMTDC dynamic simulation based on an IAT(Intra Airport Transit) in Incheon International Airport. The means(expected values) and variances of harmonic currents of single traction also are obtained by the PDF of the operating traction speed and harmonic currents. The uncertainty of harmonic currents can be calculated through the mean and variance of PDF. The probability of harmonic currents generated with the operating of arbitrary many tractions is calculated by the convolution of functions. The harmonics of different number of tractions are systematically investigated to assess the TDD(Total Demand Distortion) for the railroad system. The calculation of TDD was carried out using Monte-Carlo Simulations(MSCs) and the results of TDD evaluation of the power quality in the IAT power feeding system.

2회선 송전선로에서 상호임피던스와 고장저항을 고려한 거리계전기의 동작 특성 연구

이원석(Won-Seok Lee),정창호(Chang-Ho Jung),이준경(Jun-kyong Lee),김진오(Jin-O Kim) 대한전기학회 2003 대한전기학회 학술대회 논문집 Vol.2003 No.7