• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.3
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• pp.106-114
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• 1998

Cogging torque is often a principal source of vibration and control difficulty in permanent magnet motors, especially at low speeds and loads. For example, reduction of cogging torque is an important specification for DC motors used for electric power stee- ring. This paper examines two motor design techniques, stator tooth notching and rotor pole skewing with magnet pole shaping, for reduction of cogging torque, and the effect of each method on the airgap flux, and the use of the Maxwell stress method and Fourier decomposition to calculate the periodic cogging torque. The analyses show that the cogging torque can be nearly eliminated by the suggested designs, with minimal scacrifice of output torque.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.498-500
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• 2000

Generally, the earth resistance of distribution lines are measured under the condition of the climbing pole. This paper proposed the design technique of a new concept type remotoe automatic measuring system without climbing electric distribution poles. The worker on the earth under pole, can measure by using the CT on the located at the top of COS operating Stick. The system is useful for safety of worker, and saving mans, times for measuring.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.692-697
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• 2010

In this paper, a design program for electric railway pole foundation was developed by applying the estimation study performed by Korean Railway. There are two kinds of shapes in the cross-section of electric railway pole foundation: rectangle and circle. In foundation designing, The rectangular foundation should be satisfied with vertical, horizontal and moment equilibrium equations. On the other hand, the circular foundation should be satisfied with horizontal and moment equilibrium equations. The design program was coded into MFC(Microsoft Foundation Class) by MS Visual C. The equation's roots in the program were obtained by Incremental Search method. Dialog and property sheet(Wizard Mode) input windows were selected for user-friendliness. The biggest advantage of this program is to find an optimum depth in a given section.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.1
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• pp.20-27
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• 2001

In this paper, we propose a method for estimating the peak load of pole-transformer in summer season considering the degree of cooling load possession in customer. The cooling load of customer is selected as the most reliable parameter of peak load in summer season. The proposed estimation method is restricted to the aspect of load management for pole-transformer. The main concept of proposed method is that the error of peak load estimation using load regression equation reduces with considering the degree of cooling load possession in customer. We propose an index for estimation of cooling load possession in each customer. The proposed index is defined as cooling load possession in customer (CLPC) and obtained from the increment of monthly electric energy. The membership function for deciding the uncertainty of cooling load possession in customer is used. The database of pole-transformer in Korea Electric Power Corporation (KEPCO) is used for case studies. Through the case studies, we verify that the proposed method reduces the error of peak load estimation than the conventional method in domestic.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.402-404
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• 2000

The FRP pole had great advantages over other material poles. Light weight, easy installing and transporting were good characteristics. The material's superior properties represented the good durability for sea weather and air pollution, good insulation for electric, and changeable colors. In those properties, usages were like a area affected by sea, downtown, the area among the mountains and a special area for the outstanding views. It was studied that pole manufacturing method, structure analysis of pole by FEM in this study. Filament winding method was selected for a new pole manufacturing method. It produced the tapered poles and mechanically strong properties.

• Journal of the Korean GEO-environmental Society
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• v.13 no.11
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• pp.5-10
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• 2012

Many electric poles in the softground have been collapsed due to external load. In this study, several tests were performed with variation of numbers and depths of anchor blocks to find effects of anchor blocks on stability of concrete electric poles through earth pressure and displacement analysis. 1.50m depth of anchor block seems appropriate among three kinds of depths. The 2.25m depth of anchor block makes larger displacement due to disturbance caused by excessive excavation. The deeper anchor block, the less earth pressure of passive zone, an active earth pressure gets larger. When two anchor blocks were installed, displacement at top pole decreased 43.8% and 55.6% at ground when 1 anchor block was installed.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2274-2276
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• 1999

In this work, temperature rise and eddy current distribution on the enclosure and conductor of 3 pole gas insulated switchgear were investigated using analytical and experimental measures. The design of the diameters of the conductors and the enclosures of a meal clad gas insulated switchgear is primarily based on the insulation requirements. It is very difficult problem to predict the temperature rise of enclosed switchgear due to the complexity of the phenomena of heat transfer and existence of eddy current loss. To overcome this situations, we focused on the eddy current distribution on the enclosure of switchgear caused by high current 3 pole conductor as a fundamental basis. The experimental results about temperature distribution of 3 pole gas insulated switchgear were reported and measurements are compared with predictions of three-dimensional thermal model for eddy current analysis. As a result, three dimensional numerical analysis found to be in close relationship with experimental results and thermal model is efficient to predict the abnormal temperature rise in switchgear.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.12
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• pp.125-132
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• 2013

This paper has done a three-dimensional FEM analysis of the PM claw pole stepping motor. As magnetization happens in the z-axis, which does not have a constant value, three-dimensional FEM analysis is necessary for characteristic analysis of PM claw pole stepping motors. Because it is a type of permanent magnet motor, the PM claw pole stepping motor naturally has a detent torque. This torque is known to show negative effects on motor performance. To improve motor performance, reducing the detent torque is very important during the motor design. This paper applied DOE for optimization of stator pole design of the motor. Also, we compared motor performance by applying a different type of rotor shape, dividing the permanent magnet. To verify the simulation results, an experiment was done.

• KEPCO Journal on Electric Power and Energy
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• v.5 no.4
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• pp.257-262
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• 2019

Lattice steel towers for overhead transmission lines have been replaced by tubular steel poles due to the visual impact of large and complex shape of truss type. Demand for tubular steel poles consisting of a single frame member continues to grow because of its advantages such as visual minimization, architectural appeal and minimal site consumptions. However, there are some constraints on the transportation and construction. As the diameter of tower base has been enlarged, it may exceed minimum height limit required to pass the tunnel in case of land transportation. Also, in a narrow place where it is not easy to secure the installation areas such as mountainous places, there might be some areas wherein it must secure a wide working space so that large vehicles and working cranes will be allowed to enter. In this paper, we presented a vertical separated tubular steel pole, which is a new type of support that can be implemented for general purpose such as mountainous areas or narrow areas to improve the issues raised by breaking away from the conventional design and fabrication methods. Technical approaches for overcoming the limit of the cross-sectional size is to separate and modularize the cross-section of the tubular steel pole designed with a size that cannot be carried or assembled, and to lighten it with a weight capable of being transported and assembled in a narrow space or mountainous area. As a result of this research, it will be possible to enter small and medium sized vehicles in locations where it is restricted to transport by large-sized vehicles. In the case of mountainous areas, it will be possible to divide it into a weight capable of being carried by a helicopter and it will be easy to adjust and fabricate it with individual modules. Furthermore, in order to break away from the traditional construction method, we proposed the equipment that can be applied to the assembly of Tubular Steel Pole without using a large crane in locations where there is no accessible road or in locations wherein large cranes cannot enter. In particular, this paper shows the movable assembling equipment and some methods that are specialized for vertical separated tubular steel pole consisting of members with reduced weight. The proposed assembly equipment is a device for assembling the body of the Tubular Steel Poles. It will be installed inside the support and the modules can be lifted by using the support itself.

• Journal of the Korean Geotechnical Society
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• v.29 no.11
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• pp.85-97
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• 2013

Electric pole foundations for overhead catenary system of railroad should be designed so that they may resist significant overturning moment but relatively small vertical forces. Also they should have proper shapes to be installed at restricted narrow areas adjacent to railroad track. In this paper the moment responses of rectangular pole foundations according to their shapes were investigated numerically. A three-dimensional finite element method was developed and verified so that the numerical behaviors of the foundation resisting the overturning moments were compared reasonably well with those from an existing real-scale load test. The influences of aspect ratio, varying section with depth and loading directions for rectangular section were investigated using the developed numerical method. From the numerical results, the optimized shapes of pole foundation for more effective and economic installation adjacent to railroad track are proposed.