• Journal of the Korean Society of Safety
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• v.17 no.4
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• pp.25-30
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• 2002

This paper demonstrates the effects of dust electrical resistivity on electrostatic precipitability. The effects of gas temperature, velocity and humidity on the collection efficency were considered by used of coal fly ashes from fluidized bed combustion boiler. The experiments for collection efficiency were carried out in the pilot plant. The ashes which have non-spherical geometry and high electrical resistivity were used. Electrical resistivity is an important property for the collection efficiency in the electrostatic precipitators. Fly ash resistivity as a function of temperature up $350{\circ}C$ and water concentration(up to 15%) has been experimentally investigated using the resistivity test equipment consisted of the movable electrode, dust cup, and furnace. As the resistivity of fly ash in the operating temperature($150{\circ}C$) of an electrostatic precipitator was measured higher than $1010{\Omega}{\cdot}$cm, flue gas conditioning in the electrostatic precipitator to reduce the resistivity of fly ash is required.

• KIEE International Transactions on Power Engineering
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• v.5A no.4
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• pp.350-356
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• 2005

Earth equipments are essential to protect humans and other types of equipment from abnormal conditions. Earth resistance and potential must be restricted within a low value. An estimation algorithm of earth parameters and equivalent resistivity is introduced to calculate reliable earth resistance in this research. The proposed algorithm is based on the relationship between apparent resistances and earth parameters. The proposed algorithm, which approximates the non-linear characteristics of earth by using the Artificial Neural Network (ANN), estimates the earth parameters and equivalent resistivity. The effectiveness of the proposed method is verified with case studies.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.267-269
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• 1997

The electrical properties due to the Benzotriazole(following as BTA) additive in fluids for insulating and cooling the ultra-high voltage transformer is studied in this paper. Specimen having the several contents of BTA, such as 5[ppm]. 10[ppm] and 30[ppm] is used in order to investigate the characteristics on volume resistivity in case of fluid flow in experimental device made in lab. Volume resistivity is decreased with an increase of fluid flow velocity and increased with BTA content in low temperature region, but volume resistivity of specimen contained BTA 10[ppm] is the largest thing over $30[^{\circ}C]{\sim}50[^{\circ}C]$ than the others in experiment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.05a
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• pp.211-215
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• 1996

In this paper, the volume resistivity of transformer oil is made researches so that the electrical properties for transformer oil is investigated. The specimen is produced by the irradiation of electron beam classified into the low dose, such as 0.5[Mrad], 1[Mrad], 2[Mrad]. The effect of electron team irradiation is studied by investigating the electrical properties of dielectric liquid due to the difference of electron beam dose. To measure the physical properties of transformer oil, courier Transform-Infrared Spectroscopy is investigated. And the study far the electrical properties is made by measuring the volume resistivity of each specimen. By means of the result from this experiments, it is introduced that the movement of carrier to contribute to the volume resistivity on the electrical properties.

• Korean Journal of Materials Research
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• v.30 no.10
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• pp.522-532
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• 2020

Conductive polymer composites with high electrical and mechanical properties are in demand for bipolar plates of phosphoric acid fuel cells (PAFC). In this study, composites based on natural graphite/fluorinated ethylene propylene (FEP) and different ratios of carbon black are mixed and hot formed into bars. The overall content of natural graphite is replaced by carbon black (0.2 wt% to 3.0 wt%). It is found that the addition of carbon black reduces electrical resistivity and density. The density of composite materials added with carbon black 3.0 wt% is 2.168 g/㎤, which is 0.017 g/㎤ less than that of non-additive composites. In-plane electrical resistivity is 7.68 μΩm and through-plane electrical resistivity is 27.66 μΩm. Compared with non-additive composites, in-plane electrical resistivity decreases by 95.7 % and through-plane decreases by 95.9 %. Also, the bending strength is about 30 % improved when carbon black is added at 2.0 wt% compared to non-additive cases. The decrease of electrical resistivity of composites is estimated to stem from the carbon black, which is a conductive material located between melted FEP and acts a path for electrons; the increasing mechanical properties are estimated to result from carbon black filling up pores in the composites.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.1795-1796
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• 2006

The accurate measurement of soil resistivity and earthing system resistance is fundamental to electrical safety. However, geological and meterological factors can have a considerable effect on the accuracy of conventional measurements and the validity of the measurement methods. This paper presents optimization method of dc resistivity data acquisition system using multi-electrode arrays.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.216-217
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• 2007

In this paper we investigated the volume resistivity and AC conduction current according to the temperature and voltage. As a result, the volume resistivity comes to be small according to the measurement temperature and voltage. AC conduction current of the heat treatment specimen is increased because of the decrease of insulation.

• The Journal of Engineering Geology
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• v.22 no.4
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• pp.409-416
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• 2012

In this study, an electrical resistivity survey and a drilling investigation were conducted at an animal carcass disposal site. Chemical analysis of leachate collected from the site was also performed (sampling times: May 2011 and June 2012). Five lines of dipole-dipole electrical resistivity surveys were carried out, along with drilling investigations at 3 points within the disposal areas and 11 points near the disposal site. Two-dimensional inverse modeling of the collected resistivity data was performed to evaluate the properties (size, depth, and form) of the disposal site. Leachate analysis showed that pH of leachate decreased from 7.4 to 6.7, while Eh changed from -358 mV to -48 mV over time. In addition, dissolved ions increased due to the progression of carcass decomposition. Results of the electrical resistivity survey indicated that low resistivity zones (minimum value, $0.64{\Omega}m$) existed at a depth of 8 m from the surface. Considering the bedrock location and carcass disposal depth, there was no evidence of bedrock contamination by leachate. The results of the electrical resistivity survey are consistent with those of the drilling investigation, which indicates that electrical resistivity effectively depicted the properties of the disposal site. This study demonstrates that electrical resistivity survey is a suitable technique for investigation of animal carcass disposal sites.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.8
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• pp.381-386
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• 2006

In this study, we have investigated electrical and mechanical properties of semiconducting materials for power cable caused by CNT. Specimens were made of sheet form with the four of specimens for measurement. Volume resistivity of specimens was measured by volume resistivity meter after 10 minutes in the pre-heated oven of both $23{\pm}\;1\;[^{\circ}C]\;and\;90{\pm}\;1\;[^{\circ}C]$. And stress-strain of specimens was measured by TENSOMETER 2000. A speed of measurement was 200[mm/min], ranges of stress and strain were 400[Kgf/Cm2] and 600[%]. From this experimental results, the volume resistivity had different properties because of PTC/NTC tendency at between $23[^{\circ}C]\;and\;90[^{\circ}C]$. Also volume resistivity was low by increasing the content of CNT. It means that a small amount of CNT has a excellent electrical properties. And stress was increased, while strain was decreased by increasing the content of CNT. Thus, we could know that a small amount of CNT has a excellent electrical and mechanical oroperties.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.46-46
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• 2010

In this paper, we studied the volume resistivity and the electrical conductivity properties of nano composites to investigate the electrical properties of epoxy composites added nano MgO. The specimens were produced by classifying to 1.0, 3.0, 5.0, 10[wt%] and virgin specimen according to the addition amount of MgO. We measured the volume resistivity of nano filler using the High Resistance Meter(4329A) at the measuring temperature changed to 25, 50, 80, 100, and [$120^{\circ}C$]. As the result, it is confirmed that the volume resistivity was the highest stability and volume resistivity value is $2.6{\times}10^{17}\;[\Omega{\cdot}cm]$ at 3.0[wt%]. And it is confirmed that the electrical conductivity property is sharply increased at low electric filed region and the conductivity current density is rapidly increased at high electric filed region.