• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.3
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• pp.485-491
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• 2010

Total Transfer Capability (TTC) should be pre-determined in order to estimate Available Transfer Capability (ATC). Typically, TTC is determined by considering three categories; voltage, stability and thermal limits. Among these, thermal limits are treated mainly in this paper on the evaluation of TTC due to the relatively short transmission line length of Korea Electric Power Corporation (KEPCO) system. This paper presents a new approach to evaluate the TTC using the Dynamic Line Rating (DLR) for the thermal limit. Since the approach includes not only traditional electrical constraints but also real-time environmental constraints, this paper obtains more cost-effective and exact results. A case study using KEPCO system confirms that the proposed method is useful for real-time operation and the planning of the electricity market.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.57-58
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• 2006

As the power density and switching frequency increase, thermal analysis of power electronics system becomes imperative. The analysis provides valuable information on the semiconductor rating, long-term reliability. In this paper, thermal distribution of the Non Punchthrough(NPT) Insulated Gate Bipolar Transistor has been studied. For analysis of thermal distribution, we obtained results by using finite element simulator, Ansys and thermal distributions form experiments.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.30 no.4
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• pp.159-166
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• 2018

The Korean fenestration energy consumption efficiency rating system only considers thermal performance of the heat transfer coefficient (U-value) and airtightness excluding optical characteristics of the solar heat gain coefficient (SHGC). This study analyzed annual heating and cooling energy requirements on the middle floor of apartment by optical and thermal performance of windows to evaluate the suitability of the rating system. One hundred and twenty-eight windows were analyzed using THERM and WINDOW 7.4, and energy simulation for a reference model of an apartment house facing south was performed using TRNSYS 17. The results showed that window performance was the main factor in the heating and cooling load. The heating load of the reference model was 539 kWh to 2,022 kW, and the cooling load was 376 kWh to 1,443 kWh. The coefficient of determination ($R^2$) of the heating and cooling loads driven from the SHGC were 0.7437 and 0.9869, which are more compatible than those from the U-value, 0.0558 and 0.4781. Therefore, it is not reasonable to evaluate the energy performance of windows using only the U-value, and the Korean fenestration energy consumption efficiency rating system requires a new evaluation standard, including SHGC.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.2
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• pp.89-95
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• 2017

This study aimed to compare the primary heating energy consumption of regional apartment houses based on the enhanced thermal insulation performance of building envelope standards. The difference of the heating energy consumption based on the enhanced thermal insulation performance of building envelope standards in the southern region, the largest regional difference in primary heating energy consumption, is $10.3kWh/(m^2{\cdot}year)$. The difference of the heating energy consumption based on the enhanced thermal insulation performance of building envelope standards in the central region is $8.0{\sim}8.5kWh/(m^2{\cdot}year)$ and that of the Jeju region is $0.5kWh/(m^2{\cdot}year)$. These energy consumption differences do not result in building energy efficiency ratings changing. The building energy efficiency ratings have the possibility to be changed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.1
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• pp.7-15
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• 2017

Ambient Adjusted line Rating(AAR) method for overhead transmission lines considering Risk Tolerance(RT) was proposed in this paper. AAR is suitable for system operators to plan their operation strategy and maintenance schedule because this can be designed as a seasonal line rating. Several candidate transmission lines are chosen to apply the proposed method in the paper. As a result, it is shown that system reliability was significantly enhanced through maximizing transfer capability, solving the system constraints.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.4
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• pp.313-320
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• 2007

In this paper, the experimental study has been carried out to investigate the reliability lifetime of two bearing units based on the oil temperature. Measurements for the oil temperature as well as the bearing temperature during normal operation were performed to study the effects of oil viscosity and oil submergence percentages in the two bearing units. The optimal lubrication condition to increase the lifetime of the bearing unit A was found that its viscosity and submergence percentage were VG32 and 25%, respectively. For the bearing unit B, when the oil viscosity and submergence percent were VG32 and 75%, the lubrication condition was the most efficient. Finally, the adjusted rating times of both the bearing units were calculated to be over 28,000 h, which is greater than the minimum adjusted rating times of 25,000 h. Therefore, they satisfied the regulated lifetime of API 610.

• The Journal of Korean Obstetrics and Gynecology
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• v.28 no.4
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• pp.57-64
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• 2015

Objectives : To study correlation between Digital Infrared Thermal Imaging, Kupperman’s Index (KI) and Menopause Rating Scale (MRS) of Postmenopausal Women Methods : We analyzed 114 patients visiting Pohang Oriental Hospital from 1 ^st January 2014 to 30 ^th September 2015. The evaluating indexed of this trial were Age, DITI, KI, MRS. Temperature and different of temperature, such as In-dang (HN3), dan-Jung (CV17), gwan-won (CV4), hyup-back (LU4), no-gung (PC8), bock-to (ST31), and tae-chung (LR3). Results : Age was no correlation with DITI, KI, and MRS. There were positive correlation with KI and MRS significantly. DITI was not correlated with Age, KI and MRS, while ⊿T1 (LU4-PC8) was correlated with ⊿T2 (ST31-LR3) and ⊿T3 (CV17-CV4). Conclusions : There were non-significant correlation between DITI and Menopausal scale, but significant correlation in DITI themselves, Menopausal themselves. The More studies ar needed for the more accurate oriental medical diagnosis

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.446-447
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• 2008

In this paper, a calculation method of the short-time emergency by considering a initial load level and overload time is presented. short-time emergency analyze transient thermal rating and Long-time emergency analyze steady-state thermal rating. Using the suggested method in the paper, increasing the short-term allowable current.

• KIEAE Journal
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• v.15 no.5
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• pp.75-82
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• 2015

Purpose: The first grade of Korea's Building Energy Efficiency Rating System(BEERS) is required for new government office buildings as a mandatory measure to reduce greenhouse gas emission. However, there is no specific criteria about performance that which level should apply to energy-saving design element for obtaining Building Energy Efficiency Rating 1st grade. Therefore, Certification status should be analyzed firstly, about the office building which is certificated. Certification analysis for office buildings acquired certification therefore should be done first. Method: In this study, Certification status(Office buildings acquired Building Energy Efficiency Rating Certification)was analyzed by classified year, region, specific scale etc. And we analyzed statistically by eliciting an average value of each element influencing to the amount of energy. Result: Energy demands were gradually decreased due to revision of thermal insulation standards for enhanced u-value. Energy consumptions were different from the kind of equipment and yearly trends applied depending on the size of the building. Total primary energy consumptions were influenced by heat source types and the primary energy scale factors.

• Journal of Information Processing Systems
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• v.14 no.5
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• pp.1136-1149
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• 2018

With the increasing of urban electricity demand, making the most use of the power cable carrying capacity has become an important task in power grid system. Contrary to the rated ampacity obtained under extremely conservative conditions, this paper presents the various steady value of cable ampacity by using the changing surrounding parameters under operation, which is based on cable ampacity calculation equation under the IEC-60287 standard. To some degree, the cable ampacity analysis of actual surroundings improves the transmission capacity of cables. This paper reveals the factors that influence cable ampacity such as insulating layer thickness, allowable long-term conductor temperature, the ambient temperature, soil thermal resistance coefficient, and so on, then gives the class of the influence of these parameters on the ampacity, which plays a great role in accurately calculating the real-time ampacity and improving the utilization rate of cable in the complex external environment condition. Furthermore, the transient thermal rating of the cable is analyzed in this paper, and temperature variation of the conductor under different overload conditions is discussed, which provides effective information for the operation and control of the system.