• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.10
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• pp.123-129
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• 2010

During the past 2 decades, many electric power companies have been searching various solutions in order to supply power with economical and more efficiency in the present transmission utilities. Most interesting method to increase the line capacity of overhead transmission lines without constructing any new line might be to adapt Dynamic Line Rating(DLR). Specified rating is normally determined by any current level, not by conductor temperature. Although specified rating is essential to design transmission line, dip may be the most important factor in limiting transmission capacity. Transmission lines built by the oldest dip criterion among the 3 different design criteria for conductor dip are nearly over one-half of all Kepco's transmission lines. This paper describes an up-rating method for those transmission lines in order to apply DLR technique. Based on limit dip conductor temperature and current of the transmission lines, limitation performance and effectiveness in applying DLR with weather model are analyzed. As a result of analysis, it can be shown that an improved method could be effectively used for increasing the line rating of old transmission line which was built by the design criterion with low dip margin.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.7
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• pp.72-77
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• 2011

Dynamic Line Rating (DLR) techniques have been greatly worthy of notice for efficiently increasing transmission capacity as well as controlling load-flow in overhead transmission lines, in comparison with the existing power system operating with Static Line Rating (SLR). This paper describes an utilization method to implement DLR control system for old transmission lines built in the first stage using the ground clearance design standard with lower dips. The suggested DLR system is focused on designing as temperature control system rather than current/load control system. Based on several performance for conductor temperatures, it is shown that DLR system with efficiency can be implemented.

• 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.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.10
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• pp.426-432
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• 2006

This paper describes the concepts of Static Line Rating (SLR) and Dynamic Line Rating (DLR) and the computational methods to demonstrate them. Calculation of the line capacity needs the heat balance equation which is also used for computing the reduced tension in terms of line aging. SLR is calculated with the data from the worst condition of weather throughout the year. Even now, the utilization ratio is obtained from this SLR data in Korea. DLR is the improved method compared to SLR. A process for DLR reveals not only improved line ratings but also more accurate allowed line ratings based on line aging and real time conditions of weather. In order to reflect overhead transmission line aging in DLR, this paper proposes the method that considers the amount of decreased tension since the lines have been installed. Therefore, the continuous allowed temperature for remaining life time is newly acquired. In order to forecast DLR, this paper uses weather forecast models, and applies the concept of Thermal Overload Risk Probability (TORP). Then, the new concept of Dynamic Utilization Ratio (DUR) is defined, replacing Static Utilization Ratio (SUR). For the case study, the two main transmission lines which are responsible for the north bound power flow in the Seoul metropolitan area are chosen for computing line rating and utilization ratio. And then line rating and utilization ratio are analyzed for each transmission line, so that comparison of the present and estimated utilization ratios becomes available. Finally, this paper proves the validity of predictive DUR as the objective index, with simulations of emergency state caused by system outages, overload and so on.

• 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 the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.5
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• pp.189-197
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• 2004

The thermal rating of an overhead conductor, which is the maximum allowable current, is generally calculated on the basis of heat balance equation found in IEEE P738 standard. This is given as a function of the weather conditions such as air temperature, wind speed, wind direction, and sun heat. Wind speed among such weather parameters is strongly affected on determining the line rating when it appears very low level. Therefore there may occur inaccuracy since most anemometers used in line rating monitor systems may show low resolutions and stall speed performance. In this paper, we introduce a new methodology for determining the dynamic line rating in overhead transmission lines, without using my anemometer. It was shown that wind speed can be estimated by the temperatures of 2 indirect conductors, and through experimental study, the dynamic line rating obtained by the estimated wind speed was very closely that of weather model.

• 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.

• Journal of Information Processing Systems
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• v.13 no.5
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• pp.1358-1371
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• 2017

Dynamic thermal rating (DTR) system is an effective method to improve the capacity of existing overhead line. According to the methodology based on CIGRE (International Council on Large Electric systems) standard, ampacity values under steady-state heating balance can be calculated from ambient environmental conditions. In this study, simulation analysis of relations between parameters and ampacity is described as functional dependence, which can provide an effective basis for the design and research of overhead transmission lines. The simulation of ampacity variation in different rating scales is described in this paper, which are determined from real-time meteorological data and conductor state parameters. To test the performance of DTR in different rating scales, capacity improvement and risk level are presented. And the experimental results show that the capacity of transmission line by using DTR has significant improvement, with low probability of risk. The information of this study has an important reference value to the operation management of power grid.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.6
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• pp.158-169
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• 2004

A method for predicting the short-term dynamic line ratings in overhead transmission lines using real-time weather forecast data is proposed in this paper. Through some inspections for the 3-hour interval forecasting factors such as ambient temperature, wind speed grade and weather code given by KMA(Korea Meteorological Administration), correlation properties between forecast weather data and actual measured data are analyzed. To use these variable in determining the dynamic line ratings, they are changed into suitable numerical values. Furthermore adaptive neuro-fuzzy systems to improve reliabilities for wind speed and solar heat radiation ate designed It was verified that the forecast weather data can be used to predict the line rating with reliable. As a result it can be possible that the proposed predicting system can be effectively utilized by their anticipation a short-time in advance.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.1
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• pp.79-87
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• 2014

With the increase of demand for electricity power, new construction and expansion of transmission lines for transport have been required. However, it has been difficult to be realized by such opposition from environmental groups and residents. Therefore, the development of techniques for effective use of existing transmission lines is more needed. In this paper, the major variables to affect the allowable transmission capacity in an overhead transmission lines were selected and the dynamic line rating (DLR) method using artificial neural networks reflecting unique environment-heat properties was proposed. To prove the proposed method, the analyzed results using the artificial neural network were compared with the ones obtained from the existing method. The analyzed results using the proposed method showed an error of 0.9% within ${\pm}$, which was to be practicable.