• Proceedings of the KIEE Conference
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• 2004.07e
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• pp.27-29
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• 2004

This paper presents improved teaching and learning Gill for easily analysis tool of load flow of power system. This GUI includes not only contingency analysis function, but also calculating power loss from transmission line flow. The Gill is friendly for study for power system operation and control because picture provide a better visualizing of relationships between input parameters and effect than a tabula type result. This Gill enables topology and the output data of load flow for line outages to be shown on same picture page. Users can input the system data for power flow on the the picture and can easily see the the result diagram of bus voltage, bus power, line flow. It is also observe the effects of different types of variation of tap, shunt capacitor, loads level, line outages. Proposed Gill has been studied on the Ward-Hale 6-Bus system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.7
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• pp.1187-1193
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• 2010

This paper provides the methods for enhancing the stability with normal or emergency operating conditions in real power systems and copes with the unbalance of demand of reactive power due to the loss of facility, such as 765kV transmission line. In this paper, we focused on the maximum allowable transmission power(hereafter, MAXTP) in the metropolitan area. In order to increase the MAXTP, the application of reactive power compensators, SVC, and Shunt compensator and reactor, is analyzed as an enhancing method of stability and MAXTP. Particularly, the f-V analysis was performed for the postulated contingency, in order to evaluate the effects on SVC. Conclusively, the stability of power systems could be enhanced and the MAXTP is increased effectively with Dongseoul SVC which has the capacity 200MVAr.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.899-901
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• 1998

Continuation power flow is a tool that can trace the path of the solution from the base stable solution. However, the base stable solution cannot be calculated when the initial system load is too large to operate at a stable operating point. This case is called as unsolvable case. This paper presents implementation of the optimal load shedding algorithm on continuation power flow. It performs steady-state analysis of power systems at unsolvable case that can occur in contingency analysis. Numerical simulation on 20-bus test system demonstrates that the continuation power flow applying the optimal load shedding algorithm is robust at solvable and unsolvable cases.

• Journal of Korea Technology Innovation Society
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• v.7 no.3
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• pp.479-505
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• 2004

The purpose of this study is to investigate between CEO's Entrepreneurship in Venture Business and Organizational Effectiveness. CEO's Entrepreneurship variable consist of Innovativeness, Risk-taking and Proactiveness. Organizational effectiveness concept composed of system approach and the contingency theory and it's variable consisted of job satisfaction and organizational commitment. Statistical methods are adapted Frequency, Factor Analysis and CFA(Confirmatory Factor Analysis) of LISREL.8 program. Refined Survey data are 412/Major findings are as follows; Only Proactiveness variable of CEO's entrepreneurship have significant relation to Organizational Effectiveness(job satisfaction and organizational involvement). Innovativeness and Risk taking variables are partially supported to influence to Organizational Effectiveness.

• Journal of the Korean Society of Safety
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• v.12 no.2
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• pp.70-79
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• 1997

This paper presents a study on the fuzzy linguistic variable based approach for safety assessment of human body in ELF electromagnetic field considering power system states. To cope with the demand in modern industry, the power system becomes larger in scale, higher in voltage. The advent of high voltage system has increased the relative importance of field effects. The analysis of ELF electromagnetic field based on Quasi-Static Method is introduced while the power system is included to model the expected and/or unexpected uncertainty caused by the load fluctuation and parameter changes. In order to analyze the power system, Monte Carlo simulation method and contingency analysis method are adopted in normal state and alert state, respectively. In the safety assessment of human body, the approach based on fuzzy linguistic variable is employed to overcome the shortcomings resulting from a crisp set concept. The suggested scheme is applied to a sample system(modified IEEE 14 bus system) to validate the usefulness.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.134-136
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• 2014

차세대 에너지 관리시스템에서 계통 해석 프로그램은 집중원격감시 시스템으로부터 취득된 데이터를 이용해 토폴로지, 상태추정, 조류계산, 상정사고, 고장해석 등의 해석 정보를 계통 운영자에게 전달한다. 지속적으로 증가하는 전력수요에 신속하게 대처하기 위해서 계통 해석 프로그램은 대규모 계통의 계획과 운영을 빠르고 정확하게 분석하여 대책을 수립할 수 있어야 한다. 본 논문에서는 계통 해석 프로그램들 중 특히 많은 시간이 소요되는 상정사고 해석 프로그램의 특성을 분석하고 성능 개선 방안을 제안한다.

• Journal of Technology Innovation
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• v.13 no.3
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• pp.175-196
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• 2005

This Paper examines analytic studies of the evaluation system used for evaluating government-supported R&D Institutes (GSRIs), and designs a new model for analyzing the evaluation system's effectiveness. The analytic models in existing studies use the meta evaluation and balanced scorecard (BSC) models. However, theses studies focused on the structure and elements of the evaluation system for examples, the appropriateness of the elements within the evaluation system and the balance of the evaluation index. Accordingly, the effectiveness of the GSRI evaluation system, that is, the evaluation's influence on GSRI performance improvement was not analyzed. This study uses the institution theory and contingency theory perspectives as related to government organization management to develop an analytical model of GSRI evaluation system effectiveness. The new model proposes an analytical approach for improving the effectiveness of the GSRI evaluation system in an institutionalized environment.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.5
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• pp.185-190
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• 2006

The security analysis relates to the ability of the electric systems to survive sudden disturbances such as electric short circuits or unanticipated loss of system elements. It is composed of both steady state and dynamic security analyses, which are not two separate issues but should be considered together. In steady state security analysis including voltage security analysis, the analysis checks that the system is operated within security limits by OPF (optimal power flow) after the transition of a new operating point. On the other hand, dynamic security analysis deals that the transition will lead to an acceptable operating condition. Transient stability, which is the ability of power systems to maintain synchronism when subjected to a large disturbance, is a principal component in dynamic security analysis. Usually any loss of synchronism will cause additional outages. They make the present steady state analysis of the post-contingency condition inadequate for unstable cases. This is the reason of the need for dynamics of systems. Probabilistic criterion can be used to recognize the probabilistic nature of system components and shows the possibility of system security. A comprehensive conceptual framework for probabilistic static and dynamic assessment is presented in this paper. The simulation results of the Western System Coordinating Council (WSCC) system compare an analytical method with Monte-Carlo simulation (MCS). Also, a case study of the extended IEEE Reliability Test System (RTS) shows the efficiency of this approach.

• The Korean Journal of Ecology
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• v.9 no.3
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• pp.135-147
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• 1986

The simplification and the searching trends of complex data which assumed relationship between predictor variables and object variables are one of primary objective of ecological research. This study was aimed to apply cononical analysis consisting of canonical correlation analysis and canonical variate analysis related to lichen vegetation and several environmental variables which are elevation, height on grond, exposure side and cover values. Data collected from the Duckyoo National Park in August 1985. Lichen species was ranked by eqivocation information theory with cover values. Canonical correlation analysis was applied to one data set both set both environmental variables and lichem family. In order to make two sets of data matrix the scale of position vector ordination was calculated from the vector scalar product for lichen species. Canonical variate analysis was applied to rearranged data which was made by interval class code for environmental variables. The sharpness values was calculated in frequency of cotingency tables and the dispersion profiles of each species in classes of environmental variables was designed to extract component values based on the decomposition of expected frequencies in contingency table. The results of canonical correlation analysis revealed canonical first correlation value 0.815(89%), and second correlation value 0.083(11%). Significance test showed that the hypothesis of joint mutuallity of canonical correlation is accepted (P>0.05). The relation between canonical score of vegetation variables and that of environmental variable indicated linear tendency.

• Journal of Electrical Engineering and Technology
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• v.6 no.2
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• pp.147-153
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• 2011

This paper proposes a methodology using a tool based on the branch-parameter continuation power flow (BCPF) in order to restore the power flow solvability in unsolvable contingencies. A specified contingency from a set of transmission line contingencies is modeled, considering the transient analysis and practice in the Korean power system. This tool traces a solution path that satisfies the power flow equations with respect to the variation of the branch parameter. At a critical point, in which the branch parameter can move on to a maximum value, a sensitivity analysis with a normal vector is performed to identify the most effective compensation. With the sensitivity information, the location of the reactive power compensation is determined and the effectiveness of the sensitivity information is verified to restore the solvability. In the simulation, the proposed framework is then applied to the Korean power system.