• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.10
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• pp.1733-1740
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• 2010

KPX(Korea Power Exchange) predicts that summer peak load will be 70,700MW and system overload will be 150% from contingency analysis. This paper presents a method to operate power system at 2010 summer peak. about equipment variation, power system variation, analysis results of voltage stability, and the method to relief overload by comparing 2009 and 2010. Especially, transmission constraints to prevent global contingency in Korea power system and the role of SPS(Special Protection System) to prevent voltage collapse when fault occurs are introduced.

• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.152-155
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• 1991

The analysis and forecast of summer cooling load is one of the major concerns of utility company(KEPCO). In this paper, various methodologies to assess the weather sensitive load are introduced and the cause of remarkable growth of the summer cooling load in the last years are analized. To establish the effective measures to migrate the peak building by the summer cooling, a number of practical institutional policies are offered for future implementation.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.55 no.1
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• pp.35-40
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• 2006

Heat-pump system has a special feature that provides heating operation in winter season and cooling operation in summer season with a single system. It also has a merit that absorbs and makes use of wastewater heat, terrestrial heat, and heat energy from the air. Because heat-pump system uses midnight electric power, it decreases power peak load and is very economical as a result. By using the property that energy source is converted to low temperature when losing the heat, high temperature energy source is used to provide heating water and low temperature energy source is used to provide cooling water simultaneously in summer season. This study made up a heat-pump system with 4 air heat sources and a water heat source and implemented the optimal operation algorithm that works with numbers of heat pumps to operate them efficiently. With the heat-pump system, we applied it to cooling and heating operation in summer season operation mode in a real building.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.4
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• pp.482-488
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• 2013

Load forecasting is essential to the economical and the stable power system operations. In general, the forecasting days can be classified into weekdays, weekends, special days and special light-load periods in short-term load forecast. Special light-load periods are the consecutive holidays such as Lunar New Years holidays, Korean Thanksgiving holidays and summer special light-load period. For the weekdays and the weekends forecast, the conventional methods based on the statistics are mainly used and show excellent results for the most part. The forecast algorithms for special days yield good results also but its forecast error is relatively high than the results of the weekdays and the weekends forecast methods. For summer special light-load period, none of the previous studies have been performed ever before so if the conventional methods are applied to this period, forecasting errors of the conventional methods are considerably high. Therefore, short-term load forecast for summer special light-load period have mainly relied on the experience of power system operation experts. In this study, the trends of load profiles during summer special light-load period are classified into three patterns and new forecast algorithms for each pattern are suggested. The proposed method was tested with the last ten years' summer special light-load periods. The simulation results show the excellent average forecast error near 2%.

• Journal of Astronomy and Space Sciences
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• v.35 no.2
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• pp.83-92
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• 2018

The summer polar lower thermosphere (90-100 km) has an interesting connection to meteors, adjacent to the mesopause region attaining the lowest temperature in summer. Meteors supply condensation nuclei for charged ice particles causing polar mesospheric summer echoes (PMSE). We report the observation of meteor trail with nearly horizontal transit at high speed (20-50 km/s), and at last with re-enhanced echo power followed by diffusive echoes. Changes in phase difference between radar receivers aligned in meridional and zonal directions are used to determine variations in horizontal displacements and speeds with respect to time by taking advantage of radar interferometric analysis. The actual transit of echo target is observed along the straight pathway vertically and horizontally extended as much as a distance of at least 24 km and at most 29 km. The meteor trail initially has a signature similar to 'head echoes', with travel speeds from 20 - 50 km/s. It subsequently transforms into a different type of echo target including specular echo and then finally the power reenhanced. The reenhancement of echo power is followed by fume-like diffusive echoes, indicating sudden release of plasma as like explosive process probably involved. We discuss a possible role of meteor-triggered secondary plasma trail, such as fireball embedded with electrical discharge that continuously varies the power and transit speed.

• Journal of the Korea Society of Computer and Information
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• v.29 no.11
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• pp.31-40
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• 2024

In the summer, when the cooling load rises due to high temperatures, the hourly demand increases during the day and is relatively less at night compared to the day. These characteristics are considered important information in predicting summer electricity demand. However, if time information is simply expressed as a dummy variable, the model simply recognizes differences between time zones rather than learning changes in time. In this study, we would like to approach this problem by using a time variable using the Fourier transform. Time variables using the Fourier transform will be able to effectively learn differences between times. As a result of evaluating the type of time variable in the summer electricity demand forecast for 2022 and 2023 using the BiGRU model, the model using the time variable using Fourier transform showed the best performance with MAPE of 2.01% and 2.04% confirmed. The results of this study are expected to improve prediction accuracy in the summer when power usage increases and prevent problems such as large-scale power outages.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.427-428
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• 2007

This paper presents a study for the Korea power system at yearly peak load time in 2007 summer period. The power system become more complex due to the gradual increment of power demand. We analyze various problems in power system operation, by the use of PSS/E(power flow, fault and transient stability study) and VSAT for voltage stability. The results of power system operating plans and countermeasures are described.

• The Korean Journal of Ecology
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• v.14 no.4
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• pp.469-479
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• 1991

The abundance and local distribution of birds around the three atomic power plants were studied during summer in 1998 and winter 1989. It was particularly pointed out how to determine species diversity indices, rarefaction model appeared and habitat use. During the study over 2,200 birds were censused; black-tailed gull, terek sandpipper, asian wandering tattler and australian curlew accountedfor over 76% of the observed birds in summer. Black-tailed gull, black-headed gull, mallard, ancient murrelet and tree sparrow accounted for 76% of the observed birds in winter. overall, 53 species were occurred ; 23 have been observed on yonggwang-gun, 16 used on ulchin-gun, 12 used on kyungju-gun in summer. 18 on yonggwang-gun,,14 on ulchin-gun,12 on kyungju-gun in winter respectively. These three habitats in terms of their of species richness were computed as follows; yonggwang-gun has the highest richness with an expected species number of 17.5 as the same as two season. Kyungju-gun has the lowest with an expected species number of 8.2 in summer and 11.5 in winter.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.85-86
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• 2006

This Paper Presents a study for the Korea power system at yearly peak load time in 2006 summer period. The power system become more complex due to the gradual increment of power demand. We analyze the problems in power system operation, by the use of PSS/E(power flow, fault and transient stability study) and VSAT for voltage stability The results of establishment of power system operating plan and countermeasure are described.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.282-283
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• 2008

This paper presents a overall study results for the Korea power system at yearly peak load time in 2008 summer period. The power system become more complex due to the gradual increase of power demand. We analyze the problems in power system operation, by the use of PSS/E(power flow, fault and transient stability study) and VSAT for voltage stability. The results of establishment of power system operating plan and countermeasure are described.