• 무역상무연구
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• 제17권
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• pp.93-125
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• 2002

This paper aims to find a reasonable solvency margin system in non-life insurance industry and also to evaluate the appropriateness of the current solvency margin regulation system in Korea. The current solvency margin system in Korea, based on EU's solvency margin model, was introduced during the 1997 financial crisis. The solvency requirement is not based on non-life insurer's risk, but simply on written premiums. The current solvency margin for general insurance, such as fire, marine, and automobile insurance, is determined by the greater between a premium-based amount and a claim-based amount, where the premium-based solvency margin is calculated by multiplying the net written premium for the preceding year by the premium based solvency margin ratio. Also, the amount of solvency margin for long term insurance is set at 4% of the policy reserve of the long term insurance. Still, there exist many differences between the current solvency margin regulation system in Korea and EU's model. This paper focuses on the rationality of the solvency margin regulation system, and compares the current system in Korea with EU's model and the RBC(Risk Based Capital) system in U.S. and Japan. Finally, this paper suggests a more specific and reasonable solvency margin system to be developed in Korea.

• 전기학회논문지
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• 제63권10호
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• pp.1328-1336
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• 2014

This paper proposes Power System Health Index(PSHI) newly. The paper describes several kind of power system health indices based on two main categories, which are adequacy and security. In adequacy, four kinds of health indices of Frequency, Voltage, Reserve(Operating Reserve Power and Frequency Regulation Reserve Power) and Overload of lines and transformers are proposed. In security, four kinds of health indices of Voltage(154kV, 345kV and 765kV), Overload of lines and transformers, Power flow constraint among areas and SPS are proposed. All indices are mapped with three domains, which are indicated as Health, Margin and Risk, defined with expert interview. While domains of health, margin and risk is defined similar with the conventional well being analysis of power system. The criterion of the domains is proposed using an interview with expert operators and practical reliability codes in Korea. The several kinds of health index functions, which are linear ratio, piecewise linear ration and reverse ratio function etc. are developed in this paper. It will be expected that the developed health indices can help operators to control power system more successfully and also prevent power system from accident as like as black out in future because operator can make a decision immediately based on more easily visual information of system conditions from too much indices acquisition of complex power system.

• KIEE International Transactions on Power Engineering
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• 제11A권4호
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• pp.27-32
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• 2001

This paper presents a concept of reactive reserve based contingency constrained optimal power flow (RCCOPF). RCCOPF for enhancement of interface flow limit is composed of two modules, which are the modified continuation power flow (MCPF) and reactive optimal power flow (ROPF). In RCCOPF, two modules are repeatedly performed to increase interface flow margins of selected contingent states until satisfying the required enhancement of interface flow limit. In numerical simulation, a simple example with New England 39-bus test system is shown.

• KIEE International Transactions on Power Engineering
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• 제11권X00호
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• pp.27-32
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• 2001

This paper presents a concept of reactive reserve based contingency constrained optimal power flow (RCCOPF). RCCOPF for enhancement of interface flow limit is composed of two modules, which are the modified continuation power flow (MCPF) and reactive optimal power flow (ROPF). In RCCOPF, two modules are repeatedly performed to increase interface flow margins of selected contingent states until satisfying the required enhancement of interface flow limit. In numerical simulation, a simple example with New England 39-bus test system is shown.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(I)
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• pp.644-647
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• 1987

• 전기학회논문지P
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• 제66권1호
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• pp.7-14
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• 2017

Recently, the power consumption of industrial consumer has increased rapidly, causing problems such as lack of power reserve margin in summer and winter, and therefore there is a growing need for maximum demand power management to consumers. In this paper, we studied small microgrid system consisting of battery ESS and photovoltaic power system, applied to small and medium sized factories to reduce the maximum demand power of daily industrial power load. To verify the validity of the study, we simulated a small microgrid system using Matlab/Simulink software. As a result of applying the simulation to small and medium sized plants that consume a lot of power, it is confirmed that there is a 13% reduction in demand compared to the existing maximum demand power. This result is expected to contribute to the improvement of the power reserve margin.

• 대한전기학회논문지:전력기술부문A
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• 제53권3호
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• pp.129-134
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• 2004

The Available Transfer Capability (ATC) is defined as the measure of the transfer capability remaining in the physical transmission network for further commercial activity above already committed uses. The ATC determination s related with Total Transfer Capability (TTC) and two reliability margins-Transmission Reliability Capability (TRM) and Capacity Benefit Margin(CBM) The TRM is the component of ATC that accounts for uncertainties and safety margins. Also the TRM is the amount of transmission capability necessary to ensure that the interconnected network is secure under a reasonable range of uncertainties in system conditions. The CBM is the translation of generator capacity reserve margin determined by the Load Serving Entities. This paper describes a method for determining the TTC and TRM to calculate the ATC in the Bulk power system (HL II). TTC and TRM are calculated using Power Transfer Distribution Factor (PTDF). PTDF is implemented to find generation quantifies without violating system security and to identify the most limiting facilities in determining the network’s TTC. Reactive power is also considered to more accurate TTC calculation. TRM is calculated by alternative cases. CBM is calculated by LOLE. This paper compares ATC and TRM using suggested PTDF with using CPF. The method is illustrated using the IEEE 24 bus RTS (MRTS) in case study.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.581-583
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• 2003

일반적으로, 전력시장은 가격기능을 통하여 공급과 수요의 균형을 이룬다. 경쟁적 전력시장은 가격신호를 통하여 공급측에는 투자 유인을 북돋우고 수요측에는 수요 감소 등의 반응을 유도한다. 이와 같은 전력시장의 특성상 본질적으로 가격 변동성과 신뢰도 유지 및 확보 문제가 수반된다. 본 연구에서는 에너지 단독시장에서의 가격신호를 보완해주는 효과를 지닌 용량의무 mechanism을 선택한 PJM 시장을 중심으로 분석함으로서 해외 전력시장에서의 적정 설비공급 메커니즘을 분석하고자 한다. 따라서, 본 연구의 결과는 향후 우리의 전력시장 설계 및 운영에 일조하리라 믿는다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.339-342
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• 2006

The power outputs of renewable energy such as wind turbines and solar energy powers depend on natural sources. Accordingly, the power outputs of renewable energy is different from capacity rate at the time of peak load. Because of this gap, long term electricity power plan can have over-estimated reserve margin. So, this paper suggests the chronological approach to calculate the reliability assessment of renewable energy.

• Journal of Electrical Engineering and Technology
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• 제10권5호
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• pp.1950-1957
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• 2015

Modern wind generators (WGs) are forced or encouraged to participate in frequency control in the form of inertial and/or primary control to improve the frequency stability of power systems. To participate in primary control, WGs should perform deloaded operation that maintains reserve power using speed and/or pitch-angle control. This paper proposes an optimization formulation that allocates the required reserve to WGs to maximize the kinetic energy (KE) stored in a wind power plant (WPP). The proposed optimization formulation considers the rotor speed margin of each WG to the maximum speed limit, which is different from each other because of the wake effects in a WPP. As a result, the proposed formulation allows a WG with a lower rotor speed to retain more KE in the WPP. The performance of the proposed formulation was investigated in a 100-MW WPP consisting of 20 units of 5-MW permanent magnet synchronous generators using an EMTP-RV simulator. The results show that the proposed formulation retains the maximum amount of KE with the same reserve and successfully increases the frequency nadir in a power system by releasing the stored KE in a WPP in the case of a disturbance.