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현장 측정에 근거한 열병합 발전 시스템의 제어, 보호 해석용 EMTDC 모델 수립
김학만,신명철,Kim, Hak-Man,Shin, Myong-Chul 한국조명전기설비학회 2006 조명·전기설비학회논문지 Vol.20 No.5
열병합 발전 시스템이 급속히 보급되고 있으며, 대부분 계통 연계형으로 운전될 것으로 예상되며 안정된 계통의 운용을 위해서 연계 계통과의 보호, 제어 해석을 위한 모델이 요구된다. 본 논문에서는 열병합 발전 시스템의 제어, 보호 해석용 EMTDC 모델을 현장 계측에 근거하여 수립하였다. 그리고 특성 시험을 통하여 모델의 파라미터 정정을 하였으며 수립한 EMTDC 모델을 실 현장 시스템에 적용하여 계통 고장에 대해서 제어, 보호 등의 동특성 해석을 수행하였다. 그리고 시뮬레이션 결과를 검토하여 제시한 모델의 타당성을 보였다. Co-generation systems have been spreading rapidly over the past 10 years in Korea and most of these systems are interconnected with electric power systems. However, better control and protection models are still needed for analysis of these systems to ensure stable operation with the grid. This paper proposes improved EMTDC models for control fad protection analysis of grid-connected co-generation systems. Through on-site characteristic testing, the models were developed and the model parameters were determined. The models were applied to a field co-generation system, and analysis of control and protection was performed showing a good match to the simulation results.
Prospection of Power IT networks
김학만(Hak-Man Kim),강동주(Dong-Joo Kang) 대한전기학회 2007 대한전기학회 학술대회 논문집 Vol.2007 No.11
The importance of security is increased in power industry. Recently Power IT networks are attacked in cyber space and demage of attack become increased. For solving the problems, many research studies for network security enhancement are globally carried out in the world. In this paper, we introduce recent cyber attack cases, efforts for enhancing cyber safeness and put into perspective of potential security areas for power IT areas.
Security Issues in SCADA Network
김학만(Hak-Man Kim),강동주(Dong-Joo Kang) 대한전기학회 2007 대한전기학회 학술대회 논문집 Vol.2007 No.11
SCADA (Supervisory Control and Data Acquisition) system has been used for remote measurement and control on the critical infrastructures as well as modem industrial facilities. As cyber attacks increase on communication networks, SCADA network has been also exposed to cyber security problems. Especially, SCADA systems of energy industry such as electric power, gas and oil are vulnerable to targeted cyber attack and terrorism. Recently, many research efforts to solve the problems have made progress on SCADA network security. In this paper, we introduce recent security issue of SCADA network and propose the application of encryption method to Korea SCADA network.
BGA형 반도체 패키지의 위치정렬용 영상처리기법 오차의 통계적 분석 방법
김학만(Hak-Man Kim),성상만(Sang Man Seong),강기호(Kiho Kang) 제어로봇시스템학회 2013 제어·로봇·시스템학회 논문지 Vol.19 No.11
Pick and placement systems need high speeds and reliability for the position alignment process of semiconductor packages in picking up and placing them on placement trays. Image processing is usually adopted for position aligning where finding out the most suitable method is considered most important aspect of the process. This paper proposes a method for judging the performance of different image processing algorithms based on the PCI (Process Capability Index). The PCI is an index which represents the error distribution acquired from many experimental data. The bigger the index, the more reliable the results or the lower the deviation. Two compared and candidate methods are Hough Transform and PCA (Principal Component Analysis), both of which are very suitable for oblong or rectangular type packages such as BGA’s. Comparing the two approaches through a CPI with enough experimental results leads to the conclusion that the PCA is much better than the Hough Transform in not only reliability, but also processing speed.
부하특성이 지역간 계통의 저주파 진동 모드 해석에 미치는 영향 분석
金學萬(Hak-Man Kim) 대한전기학회 2008 전기학회논문지 Vol.57 No.10
Low frequency oscillation of inter-area system is important problem in power system areas because the operation conditions of power system depend on it. Generally, the analysis of the problem is used by small signal stability. Especially, the analysis results are affected by decision of load models. In this paper, the effect of the analysis results was studied according to load component characteristics. ZIP model, popular in large-scaled power system analysis, was used as the load model. Many cases were studied according to the component combination of ZIP model in inter-area system.