• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.4
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• pp.711-716
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• 2011

This paper defines a generator reactive reserve considering power system network. Conventional generator reserve is calculated by the difference between the maximum reactive power output of generator and the current reactive power of generator. However, all generators could not affect on the whole power system. Thus, the effective generators should be selected by sensitivity analysis. The sensitivity depends on network configuration is the relation between generator reactive power outputs and reactive power loads. Using the sensitivity, the effective generator reactive reserve can be calculated.

• Journal of Electrical Engineering and Technology
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• v.12 no.5
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• pp.1689-1696
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• 2017

In recent academic and industrial circles of the Republic of Korea, the securement of available reactive power reserve against the line faults is at issue. Thus, simulations have been performed for the securing of effective reactive power reserve (effective Q) to prepare for the line faults and improve reactive power monitoring and control methods. That is, a research has been conducted for the fast-decoupled Newton-Raphson method. In this study, a method that distinguishes source and sink regions to carry out faster provision of information in the event of line fault has been proposed. This method can perform quantification with the formula that calculates voltage variations in the line flow. The line flow and voltage changes can be easily induced by the power flow calculation performed every second in the operation system. It is expected that the proposed method will be able to contribute to securement of power system stability by securing efficient reactive power. Also, the proposed method will be able to contribute to prepare against contingencies effectively. It is not easy to prepare quickly for the situation where voltage drops rapidly due to the exhaustion of reactive power source by observing voltage information only. This paper's simulation was performed on the large scale Korean power system in steady state.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.3
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• pp.279-284
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• 2020

This paper presents the conceptual design of a cooperative control with Energy Management System (EMS) and Distribution Management System (DMS). This control enables insufficient reactive power reserve in a power transmission system to be supplemented by surplus reactive power in a power distribution system on the basis of the amount of the needed reactive power reserve calculated by the EMS. This can be achieved, because increased numbers of microgrids with distributed energy resources will be installed in the distribution system. Furthermore, the DMS with smart control strategy by using surplus reactive power in the distribution system of the area has been gradually installed in the system as well. Therefore, a kind of hierarchical voltage control and cooperative control scheme could be considered for the effective use of energy resources. A quantitative index to evaluate the current reactive power reserve of the transmission system is also required. In the paper, the algorithm for the whole cooperative control system, including Area-Q Indicator (AQI) as the index for the current reactive power reserve of a voltage control area, is devised and presented. Finally, the performance of the proposed system is proven by several simulation studies.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.3
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• pp.731-740
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• 2021

This research aims to investigate the determinants of real effective exchange rate in emerging ASEAN countries, including Indonesia, Malaysia, Philippines, Thailand, and Vietnam. The research was conducted by using quarterly time series data set from 1980Q1 to 2020Q3. Cointegration and the error correction model (ECM) methods were applied to test the long run and short run relationship of the real effective exchange rate and its determinants. The results indicate that the ratio of foreign direct investment to GDP and the government spending have significantly positive impact on real effective exchange rate in the Emerging ASEAN countries. The trade opening had influencing real effective exchange rate in most the Emerging ASEAN countries, except Vietnam. In addition, the international reserve (INR) had significant long-run impacts variables on real effective exchange rate in Malaysia, Thailand and Vietnam. In the short run equilibrium, the error collection term suggest that Indonesia and Malaysia are the fastest speed adjustment to equilibrium. In addition, the term of trade influence the real effective exchange rate in Indonesia, Malaysia, and the Philippines but it is not in Thailand and Vietnam. However, FDI is a major factor of the real effective exchange rate in Vietnam, but not for other countries.

• Journal of Electrical Engineering and Technology
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• v.11 no.5
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• pp.1108-1115
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• 2016

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.199_200
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• 2009

전통적인 발전기 무효전력 예비력은 발전기가 출력할 수 있는 최대 무효전력 출력에서 현재 운전 중인 발전기의 무효전력 출력의 차이로 계산된다. 그러나 모든 발전기가 계통에 동일한 영향을 미치는 것은 아니기 때문에 이를 개선하기 위한 방안이 필요하다. 계통 제어에 민감한 발전기들을 선정하고 보다 효용성 있는 무효전력 예비력을 산출한다. 따라서 본 논문에서는 전력 조류 방정식을 Q와 V의 관계식으로 선형화하여 발전기의 감도를 도출한다. 도출된 감도는 부하의 무효전력 변화에 대한 발전기의 무효전력 출력의 변화를 나타내는 값으로 감도를 각 발전기별 가중치로 적용해서 효용 무효전력 예비력을 계산한다.