• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.2
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• pp.111-120
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• 2004

This paper presents an application of Unified Modeling Language(UML) software technique for developing transmission pricing evaluation package. Also, this paper describes a transmission pricing algorithm applicable to a large-scale power system. The usage-based transmission pricing mechanism is very complex since it requires power flow analysis, fault current analysis, sensitivity evaluation of a transmission line, penalty factors calculation, transmission asset databases, and cost allocation rules, etc. For the efficient and flexible development of the transmission pricing package, a UML. approach is applied, which is composed of a use-case diagram, interaction diagram, class diagram, and package diagram using Rational Rose Unified Process(RUP). The designed transmission pricing package can be efficiently modified and reused as the market environments evolves since it is designed by Object-Oriented Programming(OOP).

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1102-1103
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• 2015

The researchers worldwide have been trying to apply high temperature superconducting wire for power system devices. High voltage direct current (HVDC) transmission system has been used for bulk and long-distance power transmission. The authors designed a laboratory-scale superconducting DC transmission line to investigate its applicability to an HVDC system. The superconducting DC transmission line was simulated in connection to a laboratory-scale HVDC system using PSCAD/EMTDC. The operating characteristics of the superconducting DC transmission line connected to HVDC system and the effects of the superconducting DC transmission line on HVDC system were analyzed and compared with the results of a conventional DC transmission line. The results of operating characteristics for the superconducting DC transmission line were discussed in detail.

• Journal of Biosystems Engineering
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• v.16 no.3
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• pp.239-247
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• 1991

This study was conducted to investigate the feasbility of continuously variable V-belt transmission(CVVT) as automatic power transmission system of combine harvesters. An experimental set-up for testing the performance of CVVT and the automatic transmission system was designed and used to analyze the power transmission characteristics of CVVT. The transmission efficiency of CVVT was increased logarithmically with increase of the load of driven shaft, but was not affected by the speed ratios of transmission. More than 80% of transmission efficiency was obtained in the 25N-m load and more of driven-shaft, and the maximum efficiency was 88~91%. When rapid speed change of the CVVT was attempted, the speed of driven shaft was stabilized within about 0.4 seconds after shift operation in both cases of increasing and decreasing of the speed.

• Transactions of The Korea Fluid Power Systems Society
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• v.1 no.2
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• pp.20-25
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• 2004

In this study, a position control characteristics of pneumatic cylinder with transmission line is analyzed. Dynamic characteristics of transmission line using compressible fluid is changed by the flowing stiles of the fluid the diameter and the length of the line. But, the effect of the change of dynamic characteristics of transmission line by the flowing states on the position control characteristics can be neglected because of the friction force of the pneumatic cylinder. So, We assume that the position control characteristics is affected by the diameter and length of the transmission line. The experimental results according to the change of parameter of the transmission line show that the relation between the parameter of the transmission line and the position control characteristics of pneumatic cylinder driving system with the transmission line.

• 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.

• KEPCO Journal on Electric Power and Energy
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• v.4 no.2
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• pp.115-123
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• 2018

Various types of robots running on power transmission lines have been developed for the purpose of line patrol monitoring. They usually have complex mechanism to run and avoid obstacles on the power line, but nevertheless did not show satisfactory performance for going over the obstacles. Moreover, they were so heavy that they could not be easily installed on the lines. To compensate these problems, flying robots have been developed and recently, multi-copter drones with flight stability have been used in the electric power industry. The drones could be remotely controlled by human operators to monitor power distribution lines. In the case of transmission line patrol, however, transmission towers are huge and their spans are very long, and thus, it is very difficult for the pilot to control the patrol drones with the naked eye from a long distance away. This means that the risk of a drone crash onto electric power facilities always resides. In addition, there exists another danger of electromagnetic interference with the drones on autopilot waypoint tracking under ultra-high voltage environments. This paper presents a patrol monitoring plan of autopilot drones for power transmission lines and its field tests. First, the magnetic field effect on an autopilot patrol drone is investigated. Then, how to build the flight path to avoid the magnetic interference is proposed and our autopilot drone system is introduced. Finally, the effectiveness of the proposed patrol plan is confirmed through its field test results in the 154 kV, 345 kV and 765 kV transmission lines in Chungcheongnam-do.

• Journal of Biosystems Engineering
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• v.36 no.6
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• pp.422-433
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• 2011

Market demand for hydro-mechanical transmission (HMT) for agricultural tractors has increased recently. To select a type of HMT satisfying design conditions, performance characteristics of 12 HMT types must be understood. This study was conducted to provide tractor engineers with a guideline to select the most appropriate HMT type for their design requirements. Characteristics on speed reduction ratio, power transmission efficiency, power regeneration, lock-up angular velocity, output torque ratio and torque ratio of planetary gear train axis of the 12 HMT types were investigated and presented as either formula or graphical forms. A guideline to select proper HMT type was also presented using 2 parameter: lock-up angular velocity (${\omega}_L$) and torque ratio of the planetary gear train axis. In addition, effect of gear ratio of the planetary gear train on the power transmission efficiency was investigated and a guideline to select the best gear ratio was also presented.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1759-1764
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• 2015

Glow corona is a kind of streamer-free corona that can suppress upward leaders in transmission lines. Thus, it has good application potential in lightning protection. This paper investigates its corona characteristics. The suppression characteristic of glow corona on streamer is studied in air gap under negative DC voltage by wrapping thin wires on the electrode. The effect of thin wire winding patterns on the gap breakdown voltage is analyzed. Results are considered to be attributed to the inception condition of glow corona. Thus an inception test of glow corona is also conducted, and the inception voltage is obtained. Results show that the inception voltage decreases with short winding pitch. Thus an investigation on the inception of glow corona influenced by thin wire is conducted, and an influential factor is proposed to evaluate the influence. The inception regular of thin wire glow corona presented in this paper has certain reference value for the application of glow corona in transmission lines.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.8
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• pp.412-417
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• 2000

TV ghost interference can be described as passive interference by the conducting part of transmission lines. In order to survey this interference from large-sized overhead EHV (extra high voltage) transmission line, TV reception quality was measured in the vicinity of that before and after construction. Instrumentation system was composed of ghost analyzer, TV received field intensity meter, VHF/UHF antennas, TV monitor and so on. The system is installed inside the vehicle. TV field intensity and PDUR (Perceived Desired wave to Undersired wave Ratio) are measured to evaluate TV ghost by using the system and vehicle. As the results, the useful data, which can be used to evaluate the effect of TV ghost interference from transmission lines could be obtained. In this paper, it is shown that the range of TV ghost interference from transmission lines can vary according to the frequency of TV electromagnetic wave, an incidence angle to the line and the other conditiions. At present, we are making efforts to establish a PDUR guideline for transmission lines.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.10
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• pp.1761-1769
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• 2010

This paper describes switching surge analysis on reclosing decision in 154kV combined transmission line with power cables. Reclosing should be operated in combined transmission line based on the technical evaluation because of insulation problem of power cable section. If the surge strikes on power cable, the breakdown can occur at week point of cable insulation. Therefore the detailed analysis is required by considering several conditions such as length ratio of power cable, arrester, fault resistance, charging rate and grounding resistance, etc.. In addition, sheath voltage on IJ(Insulated Joint) is analyzed to confirm the protective level. Simulation is performed by EMTP/ATP. Analysis results show that reclosing can be operated without any special problem by the single line-to-ground fault with fault resistance of $1\Omega$ to $50\Omega$ occurred at the overhead transmission section in 154kV combined transmission lines and trap charge of 100% and 110%.