• KIEAE Journal
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• v.16 no.2
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• pp.33-41
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• 2016

Purpose: The window energy rating system was developed in early 1990's and various kind of rating system has been implemented in advanced country such as Europe, Australia, Canada and the US since 2000. In Korea, the Energy Consumption Efficiency Rating Indication System has been implemented to promote supply of high efficiency window since July 2012. Normally, the window energy rating system based on heat balance which considers both thermal losses and solar heat gain is used and applied only to residential buildings. However, the system used nationally only considers thermal losses and is applied to every building regardless of its usage. Therefore, in this study, we indicated problems of domestic window energy rating system and looked for improvements. Method: We analyzed thermal performance of various windows through dynamic simulation applied to detached house and compared results with those of domestic and foreign rating system. Result : Thermal performance of south windows is more affected by SHGC than U-value, and that of north windows is also affected by SHGC a lot. The difference between the results of our study and current system is statistically significant. As a result, appropriate evaluation criteria which considers solar heat gain is required.

• Journal of Information Processing Systems
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• v.15 no.4
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• pp.724-736
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• 2019

Dynamic thermal rating technology can effectively improve the thermal load capacity of transmission lines. However, its availability is limited by the quantity and high cost of the hardware facilities. This paper proposes a new dynamic thermal rating technology based on global/regional assimilation and prediction system (GRAPES) and geographic information system (GIS). The paper will also explore the method of obtaining any point meteorological data along the transmission line by using GRAPES and GIS, and provide the strategy of extracting and decoding meteorological data. In this paper, the accuracy of numerical weather prediction was verified from the perspective of time and space. Also, the 750-kV transmission line in Shaanxi Province is considered as an example to analyze. The results of the study indicate that dynamic thermal rating based on GRAPES and GIS can fully excavate the line power potential without additional cost on hardware, which saves a lot of investment.

• Journal of IKEEE
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• v.16 no.1
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• pp.1-6
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• 2012

Thermal rating or lifetime evaluation for aged overhead transmission line becomes more important concerns with respect to keeping power delivery stable having proper capability. Both load rating and dip/clearance are essential factors to determine transmission capacity. In order to evaluate thermal rating and conductor lifetime for domestic transmission lines with double-circuit, the dip/ground clearance standards as well as the electrical equipment technical standard are examined. Conductor temperature and dip are calculated under the assumption of a contingency, and then, a method to up-rate load capacity is searched. As thermal rating and limit dip for aged conductor are properly evaluated, an improved strategy in order to guarantee the existing power system reliability is presented in this paper.

• Journal of Information Processing Systems
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• v.15 no.2
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• pp.386-398
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• 2019

The transmission capacity of transmission lines is affected by environmental parameters such as ambient temperature, wind speed, wind direction and so on. The environmental parameters can be measured by the installed measuring devices. However, it is impossible to install the environmental measuring devices throughout the line, especially considering economic cost of power grid. Taking into account the limited number of measuring devices and the distribution characteristics of environment parameters and transmission lines, this paper first studies the environmental parameter estimating method of inverse distance weighted interpolation and ordinary Kriging interpolation. Dynamic thermal rating of transmission lines based on IEEE standard and CIGRE standard thermal equivalent equation is researched and the key parameters that affect the load capacity of overhead lines is identified. Finally, the distributed thermal rating of transmission line is realized by using the data obtained from China meteorological data network. The cost of the environmental measurement device is reduced, and the accuracy of dynamic rating is improved.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.5
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• pp.738-744
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• 2016

Current rating of a power cable can be calculated by the maximum allowable temperature in an insulating material considering the heat transfer from cable conductor. Therefore, it is very important to calculate the current rating using electrical equivalent circuit by calculated cable thermal circuit parameters but, it has not been fully investigated yet. In this paper, in order to determine the current rating of power cable, conventional calculation method has been reviewed considering the conductor resistance, loss factor of sheath, dielectric losses and thermal resistances based on the maximum allowable temperature of 345 kV $2500mm^2$ XLPE cable. To confirm the calculation result of the current rating, the conductor temperature should be examined whether it reaches the maximum allowable temperature by the thermal equivalent circuit of the cable. Then, utilizing EMTP (Electro-Magnetic Transient Program) which is a conventional program for electrical circuit, the thermal equivalent circuit was transformed to an electric equivalent circuit using an analogous relationship between thermal circuit and electrical circuit, and temperature condition including cable conductor, sheath, cable jacket could be calculated by the current rating of 345 kV $2500mm^2$ XLPE cable.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.7
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• pp.273-280
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• 2006

This paper suggests the method that forecasts Dynamic Line Rating (DLR). Thermal Overload Risk Probability (TORP) of the next time is forecasted based on the present weather conditions and DLR value by Monte Carlo Simulation (MCS). To model weather elements of transmission line for MCS process, this paper will propose the use of statistical weather models that time series is applied. Also, through the case study, it is confirmed that the forecasted TORP can be utilized as a criterion that decides DLR of next time. In short, proposed method may be used usefully to keep security and reliability of transmission line by forecasting transmission capacity of the next time.

• Journal of Information Processing Systems
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• v.15 no.3
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• pp.464-477
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• 2019

With the sustained and rapid development of new energy sources, the demand for electric energy is increasing day by day. However, China's energy distribution is not balanced, and the construction of transmission lines is in a serious lag behind the improvement of generating capacity. So there is an urgent need to increase the utilization of transmission capacity. The transmission capacity is mainly limited by the maximum allowable operating temperature of conductor. At present, the evaluation of transmission capacity mostly adopts the static thermal rating (STR) method under severe environment. Dynamic thermal rating (DTR) technique can improve the utilization of transmission capacity to a certain extent. In this paper, the meteorological parameters affecting the conductor temperature are analyzed with the IEEE standard thermal equivalent equation of overhead transmission lines, and the real load capacity of 220 kV transmission line is calculated with 7-year actual meteorological data in Weihai. Finally, the thermal load capacity of DTR relative to STR under given confidence is analyzed. By identifying the key parameters that affect the thermal rating and analyzing the relevant environmental parameters that affect the conductor temperature, this paper provides a theoretical basis for the wind power grid integration and grid intelligence. The results show that the thermal load potential of transmission lines can be effectively excavated by DTR, which provides a theoretical basis for improving the absorptive capacity of power grid.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.706-711
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• 2009

Energy shortage and environmental pollution caused by fossil fuels are very serious problem. Especially buildings have consumed more and more energy, and buildings are spend up to 25% of total energy consumption. So we should prepare alternatives to save energy in buildings. In apartment houses, The efficiency of thermal insulators and window glasses is very important to curtail heating energy. In this study, the energy rating of Apartment building is evaluated by applying various thermal insulators and window glasses.

• Journal of Electrical Engineering and Technology
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• v.12 no.2
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• pp.576-585
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• 2017

Dynamic thermal rating (DTR) of overhead transmission lines can provide a significant increase in transmission capacity compared to the static thermal rating. However, the DTR are usually estimated by the traditional thermal model of overhead conductor that is highly dependent on the solar, wind speed and wind direction data. Consequently, the estimated DTR would be unreliable and the safety of transmission lines would be reduced when the solar and wind sensors are out of function. To address this issue, this study proposed a novel thermal model of overhead conductor based on the thermal-electric analogy theory and Markov chain. Using this thermal model, the random variation of conductor temperature can be simulated with any specific current level and ambient temperature, even if the solar and wind sensors are out of function or uninstalled. On this basis, an estimation method was proposed to determine the DTR in the form of probability. The laboratory experiments prove that the proposed method can estimate the DTR reliably without measured solar and wind data.

• KIEAE Journal
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• v.7 no.5
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• pp.65-71
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• 2007

The purpose of this study was to analyze the difference of thermal sensation by radiant floor heating as ecological design element. The experimental investigations were carried out in climate chamber, and subjects were 34 college-age females in good health. The experimental variable was radiant heat by floor heating, and experimental controlled conditions were indoor temperature, relative humidity, and air velocity in climate chamber and clothing value and activity of subjects. The results are as follows. (1) Indoor temperature($21{\pm}0.5^{\circ}C$) in climate chamber were maintained as controlling. Clothing values of the subjects were controlled as average 0.73 clo. In the floor heating-off, globe temperature was average $23.2^{\circ}C$(22.4~24.1), but in the floor heating-on, globe temperature was average $24.8^{\circ}C$(23.0~25.5). (2) In the floor heating-off, thermal sensation rating was average -1.03(slightly cool), in the floor heating-on, thermal sensation rating was average +1.03(slightly warm). (3) There were the differences of thermal sensation by radiant floor heating although indoor temperatures were maintained in an equal state. (4) The thermal sensation rating was tending upward according as the globe temperature was getting higher.