• Current Optics and Photonics
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• v.2 no.4
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• pp.348-355
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• 2018

How to measure the creepage distance of an insulator quickly and accurately is a problem for the power industry at present, and the noticeable concern is that the high voltage insulation equipment cannot be measured online in the charged state. In view of this situation, we develop an on-line measurement system of creepage distance for high voltage insulators based on binocular stereo vision. We have proposed a method of generating linear structured light using a conical off-axis mirror. The feasibility and effect of two ways to solve the interference problem of strong sunlight have been discussed, one way is to use bandpass filters to enhance the contrast ratio of linear structured light in the images, and the other way is to process the images with adaptive threshold segmentation and feature point extraction. After the system is calibrated, we tested the measurement error of the on-line measurement system with a composite insulator sample. Experimental results show that the maximum relative error is 1.45% and the average relative error is 0.69%, which satisfies the task requirement of not more than 5% of the maximum relative error.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.271-274
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• 2007

Housing and insulation of electrical connectors are made of plastic resin by injection molding process. The metallic inner tube is easily deformed by high pressure during the injection process. In order to prevent deformation of the inner tube, it is desirable to simulate it by structural CAE analysis. However, it takes a long time to calculate the stress- of the part by commercially available injection molding CAE software with sufficient accuracy. In this study, structural analysis in conjunction with injection molding analysis is proposed to improve accuracy of the structural analysis. Pressure distribution on the inner tube is predicted by the injection molding CAE analysis, and then mapped onto the mesh of structural analysis by a mapping algorithm developed in this study. As a result reliable result is obtained in shorter time than the conventional method. The predicted deformation of the inner tube is compared with the actual part after experiment.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.1
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• pp.61-66
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• 2014

The evaporative cooling technology used in Wind generator stator has unique advantages. Combined with the structure of motor stator and operating conditions, this report based on the research project for the evaporative cooling sleeve of the 3.6MW wind generator, introduces the material requirements and structural characteristics of the sleeve, simulates on the stress, displacement and stability by finite analysis method, and tests the products experimentally. The research results show that the epoxy resin-glass materials have a higher strength and better insulation properties, but the evaporative cooling of the wind generator stator sleeve, because of its thin-walled, and the external pressure, so it's the less rigid. Should make full use of the motor stator core structure, increase its stiffness and improve the stability of the epoxy resin-glass sleeve, which for thin-walled the epoxy resinglass sleeve on the successful application of wind turbines has played an important role.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.8
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• pp.354-360
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• 2002

The partial discharge detecting method using the ultrasonic technique has been investigated to monitor the insulation ageing of a transformer. However, the result of the studies on the ultrasonic technique for detecting of partial discharge in the operating transformer is not enough yet to utilize. This paper presents the analysis of the ultrasonic signals due to the partial discharge in a model transformer and the corona in air at a shielded high voltage room. In addition, the ultrasonic signals due to the vibration from the core, operation of the cooling pump, the fan and the OLTC at the 345㎸ power transformer, were analyzed and corona noise from overhead transmission line in 345㎸ substation were measured to remove the electrical and mechanical noises from the transformer. Furthermore, ultrasonic signal due to the partial discharge in the 154㎸ power transformer with in $C_2$$H_2$ gas warning condition was measured. The inside of the transformer was examined with care. which confirms the existence of the partial discharge source.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.704-707
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• 1999

Partial discharge(PD) in air insulated electric power systems is responsible for considerable power lossesfrom high voltage transmission lines. PD in air often leads to deterioration of insulation by the combined action of the discharge ions bombarding the surface and the action of chemical compounds that are formed by the discharge and may give rise to interference in ommunication systems. PD can indicate incipient failure. Thus understanding and classification of PD in air is very important to discern source of PD. In this paper, we investigated PD in air by using statical method. We classified air discharge with corona, surface discharge and cavity discharge by source of discharge. we used the mean pulse-height phase distribution $H_{qmean}(\psi)$, the max pulse-height phase distribution $H_{qmax}(\psi)$ , the pulse count phase distribution $H_n(\psi)$ and the max pulse height vs. repetition rate $H_{q}(n)$ for analysis PD pattern. We used statistical operators, such as skewness(S+. S-1, kurtosis(K+, K-), mean phase(AP+. AP-), cross-correlation factor(CC) and asymmetry from the distribution.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.712-715
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• 1999

Treeing has a profit to observe processing electrical breakdown because it gives degradation steps of insulation material by optical method. But, reappearance properly of treeing is not so good and precise quantization of tree growth is not so easy because tree Patterns are very complicate. The study on tree growth using image processing is predicted to precision of tree degradation and possible to quality measurement of tree pattern. In this paper, degradation steps are analyzed by image processing, therefore precision and realiability of tree growth are increased. Also, processing of tree degradation is quantized by fractal.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1497-1499
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• 2000

We give pressure stimulation into organic thin films and then manufacture a device under the accumulation condition that the state surface pressure is 30 [mN/m]. LB layers of Arac. acid deposited by LB method were deposited onto y-type silicon wafer as y-type film. In processing of a device manufacture. we can see the process is good from the change of a surface pressure for organic thin films and transfer ratio of area per molecule. The structure of manufactured device is Au/arachidic acid/Al. the number of accumulated layers are 9$\sim$21. Also. we then examined of the MIM device by means of I-V. The I-V characteristic of the device is measured from -3 to +3[V]. The insulation property of a thin film is better as the distance between electrodes is larger.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.10a
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• pp.226-229
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• 2003

Following the successful development of practical high temperature superconducting (HTS) wires, there has been renewed activity in the development of superconducting power equipments. HTS equipments must be operated in the coolant, such as liquid nitrogen (L$N_2$) or cooled by cooler, such as GM-cryocooler to maintain the temperature below critical temperature. In this paper, dielectric strength of some insulating materials, such as epoxy, teflon, and glass fiber reinforced plastic (GFRP) in L$N_2$was measured. Surface breakdown voltage of GFRP which is basic property in design of HTS solenoid coil was measured. Epoxy is a goof insulating material but it is fragile at cryogenic temperature. The multi-layer insulating method of current lead is suggested to compensate this fragile property. It consists of teflon tape layer and epoxy layer fixed with texture. Based on these measurements, the 6.6㎸ class HTS magnet for DC reactor type high-T$_{c}$ superconducting fault current limiter (SFCL) was successfully fabricated and tested.d.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.7 no.4
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• pp.633-641
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• 1995

The effect of the gap width on conjugate heat transfer in the cylindrical annulus for an insulated tube has been studied numerically by the finite difference method. The parameters considered here are the Rayleigh number, Ra, the dimensionless insulated wall thickness, $W/D_i$ and the dimensionless gap width, S/W. As S/W increases, the mean wall temperature increases at the inside wall of annulus and decreases at the outside walls of annulus and the insulated tube at $S/W{\leq}0.5$, and then slightly increases at $Re=10^4$, $W/D_i=1.47$. The heat transfer rate decreases at $S/W{\leq}0.5$ and then increases apparently as S/W increases at $Re=10^4$, W/Df=1.47. Therefore, it is considered that $$S/W{\sim_=}0.5$$ is the optimum gap width for the effect of insulation at $Re=10^4$, $W/D_f=1.47$.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.11
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• pp.789-796
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• 2007

It has been noted, in case of the apartments in collective form, the drainage noise from cleaning of toilet causes many problems in the basement and adjacent rooms, mainly hampering the pleasant housing environment. The problems are increasingly raised by civil complaints with the public offices. Therefore, if the drainage noise generates when wash out of toilet bowl is grasped how the characteristics change according to the sorts of drainpipe, it is considered that the establishment of an effective sound insulation countermeasure could be possible when a civil petition against the drainage noise of apartment house is submitted hereafter. On such viewpoint, this study measured and analyzed the characteristics of drainage noise per the type of drainage pipe, according to KS A ISO $1996-1{\sim}3$, with the horizontal branch pipe and riser pipes in the drainage noise experiment chamber which has the characteristics of the anechoic room. In the result, the pipe type with excellent noise reduction function. The result of this study is considered to become available as fundamental data, to take actions on reduction of drainage noise of the ceiling piping method.