• Journal of the Earthquake Engineering Society of Korea
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• v.22 no.3
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• pp.149-160
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• 2018

This study experimentally and analytically examines the seismic vulnerability of steel rack storage frames subjected to Korea earthquakes (2016 Gyeongju earthquake and 2017 Pohang earthquake). To achieve this aim, this study selects a three-story, one-bay steel rack frame with a typical configuration of rack frame in Korea. Firstly, the local behavior for frame components is examined by performing monotonic and/or cyclic load tests and the global response and dynamic characteristics of the subject rack frame are investigated by conducting a shaking table test. The analytical model of the rack frame is then created based on the experimental results and is used to perform nonlinear time history analyses with recorded Korea earthquakes. The seismic demand of the rack frame is considerably affected by the spectral acceleration response, instead of peak ground accelerations (peak floor accelerations). Moreover, the collapse fragility curve of the rack frame is developed using incremental dynamic analyses for the Gyeongju and Pohang earthquakes. Fragility results indicate that the ground motion characteristics of these earthquakes do not significantly affect the frame vulnerability at the collapse state.

• Journal of Advanced Marine Engineering and Technology
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• v.14 no.4
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• pp.57-66
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• 1990

In the design of an electric power plant, the capacity to meet the peak load demand is one of the important factors to be considered. This peak load usually occurs when the most of the cooling air conditioning systems are being operated during daytime in summer season, which inevitably entails the construction of an additional electric power plant. This study is aimed to carry out a basic experiment for the development of a cooling air conditioning system using the ice energy by the surplus electric power during the night-time. The experimental apparatus consists of four major parts; (1) the heating section consisting of the air duct and I.D. fan, (2) the cold section with the ice chamber, (3) the bundle of heat pipes made in a form of the staggered arrangement with ${C_y}/{d_o}$=2.0 and ${C_x}/{d_o}$=1.73, (4) the refrigerator system to cool down the ice chamber. This study involves an intensive experiment concerning the convective heat transfer of the air flow surrounding the bundle of heat pipes. This major experimental parameters are the amount of working fluid, the velocity of air and the working temperature. The major findings of the present study are as follows; (1) The optimum amount of the working fluid necessary for the horizontal heat pipes is much more than that for the vertical type. (2) The convective heat transfer coefficients of the air are coincided with the empirical equations of Grimson and ${\breve{Z}ukauskas}$. (3) The equation of the mean heat transfer coefficient obtained in the present study is ${N_um}=0.32 {Re_max^{0.63}}$.

• Journal of IKEEE
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• v.18 no.4
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• pp.442-446
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• 2014

A method for applying emergency ratings to improve the reliability of power supply in ACSR overhead transmission lines is described in this paper. Due to re-regulate power industry, most power companies worldwide as well KEPCO have been searching for only economical strategies without new investment. Power demand was rapidly increasing, however, generation amount did not follow sufficiently. Hence in order to increase the transmission capacity for the existing transmission lines in case of peak load, or contingency in transmission lines, an application method of emergency ratings such as short or long term rating is proposed. If applying long term emergency rating instead of static line rating for the period of a peak load, power transmission can be increased to 10 % or more. Furthermore, it was shown that emergency rating can be effectively used in the contingency of double-circuit transmission lines and/or overload cases.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.9
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• pp.55-61
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• 2008

Because of the high increasing rate of load demand these days the necessity of deciding what optimum reserve level is appropriate to most stably supply electricity is being emphasized. This research studies the downward tendency of reserve ratio by analyzing the trend of change of the network scale, reserve, and reserve ratio while optimum reserve has been increased as the network system scale grow up. This means, at this moment 6,000[MW] is optimum level for short term prospect of power supply and demand. And also, it has been analyzed that, as the annual peak load exceeded 50,000[MW], confirming the amount of optimum reserve level is more stable than keeping 10 to 12[%] reserve ratio.

• KEPCO Journal on Electric Power and Energy
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• v.7 no.2
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• pp.329-333
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• 2021

V2G (Vehicle to Grid) technology for an EV (Electric Vehicle) has been assumed as so promising in a near future for its useful energy resource concept but still yet to be developed around the world for specific service purposes through various R&BD projects. Basically, V2G returns power stored in vehicle at a cheaper or unused time to the grid at more expensive or highly peaked time, and is accordingly supposed to provide such roles like peak shaving or load levelling according to customer load curve, frequency regulation or ancillary reserves, and balancing power fluctuation to grid from the weather-sensitive renewable sources like wind or solar generations. However, it has recently been debated over its prominent usage as diffusing EVs and the required charging/discharging infrastructure, partially for its addition of EV ownership costs with more frequent charging/discharging events and user inconvenience with a relative long-time participation in the previously engaged V2G program. This study suggests that a Korean DR (Demand Response) service integrated V2G system especially based upon a dynamic charge/pause/discharge scheme newly proposed to ISO/IEC 15118 rev. 2 can deal with these concerns with more profitable business model, while fully making up for the additional component (ex. battery) and service costs. It also indicates that the optimum economic, environmental, and grid impacts can be simulated for this V2G-DR service particularly designed for EV aggregators (V2G service providers) by proposing a specific V2G engagement program for the mediated DR service providers and the distributed EV owners.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.461-462
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• 2016

본 논문은 100kW 급 비상발전용 ESS 상용화 개발을 제안한다. 비상발전기란 전력계통이 정지되었을 때 발전장치를 구동시켜 전력을 생산하는 자가발전설비를 말한다. 제안하는 시스템은 2Level 전압형 100kW 급 비상발전용 ESS 로써 정상 시 계통 전원과 동기 운전을 수행하는 계통 연계형 전력변환장치이다. 수배전 수용가에 설치되어 운영이 가능하며 일반적인 ESS PCS 기능인 주파수 조정 (Frequency Regulation), 출력 안정화, 첨두부하 저감 (Peak Shaving), 부하평준화 (Load Leveling), 수요반응 (Demand Response)에 추가하여, 자가발전 (Black Start), 무효전력제어 등의 기능을 적용 하였다. 제안된 100kW 급 비상발전기용 ESS PCS 는 시뮬레이션 및 프로토 타입을 이용하여 성능을 검증하였다.

• 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.

• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.760-762
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• 1998

Due to the reinforcement of government's DSM(Demand Side Management) policy. Solid State Meter was introduced in Korea since 1993 and it is applied to the high voltage customer exceeding 100kW in order to equalize daily load curve. In recent days, KEPCO has a Plan to use the Solid State Meter which has a data recording and remote meter-reading function for low voltage customer to introduce the real-time pricing system and reduce peak power in the near future. So, this paper suggests the specification and function of Solid State Meter.

• International Journal of High-Rise Buildings
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• v.6 no.2
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• pp.197-205
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• 2017

The conflict between indoor environmental quality and energy consumption has become an unneglectable problem for highrise office buildings, where occupants' productivity is highly affected by their working environment. An effective Façade, therefore, should play the role of an active building skin by adapting to the ever-changing external environment and internal requirements. This paper explores the energy-saving and indoor environment-improving potential of a phase-change material (PCM) integrated Façade. Building performance simulations, combined with parametric study and sensitivity analysis, are adopted in this research. The result quantifies the potential of a PCM-integrated Façade with different configurations and PCM properties, taking as an example a south-oriented typical office room in Shanghai. It is found that a melting temperature of around $22^{\circ}C$ for the PCM layer is optimal. Compared to a conventional Façade, a PCM-integrated Façade effectively reduces total energy use, peak heating/cooling load, and operative temperature fluctuation during the periods of May-July and November-December.