• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.3
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• pp.45-50
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• 1998

This paper presents experimental results on the application of very low frequency(VLF) voltage to replace conventional DC test as an after laying test for underground distribution cables. We carried out several tests to prove defects detecting ability of VLF test on the 5m length real cables having knife-cut or needle type defects which is made in our La.. Through this experiment we proved it is very difficult to initiate electrical tree from the defects inside of the cable insulation but once the electrical tree is initiated it grows very fast and VLF does not make new defects and expand the defect. Therefore VLF test equipment for quality inspection test of manufacture is more effective than field application for underground distribution cables.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.9
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• pp.59-64
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• 2015

IEC is an international standards which are used in many countries with Europe as the center. IEC standard is introduced in Korea according to WTO/TBT agreements, however until now there are no buildings in Korea which are designed applying IEC standard. Therefore, KEA(Korea Electric Association) is scheduled to construct Korean low voltage electrical installation integration test site which is designed applying IEC standard. In this paper, before being under construction of Korean low voltage electrical installation integration test site, power substation is modeled based on real design parameters and method to select circuit breakers and cables is presented applying IEC standard in the modeled power substation. EMTP(ElctroMagnetic Transient Program) is used for simulation program. EMTP which is power system analysis program is easy to model power system and power substation.

• Journal of Electrical Engineering and Technology
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• v.11 no.3
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• pp.699-706
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• 2016

Partial discharges (PD) lead to the degradation of high voltage cables and accessories. PD activities occur due to the existence of impurities, voids, contaminants, defects and protrusions during the manufacture and installation of power cables. Commonly, insulation failures occur at cable joints and terminations, caused by inhomogeneous electric field distributions. In this work, a blend of natural rubber (NR) and linear low density polyethylene (LLDPE) was investigated, and the optimal formulation of the blend that could resist PD was discussed. The experiments were conducted under a constant high voltage stress test of 6.5 kV AC and the magnitude of partial discharge activities was recorded using the CIGRE method II. Pattern analysis of PD signals was performed along with the interpretation of morphological changes. The results showed that the addition of 10 wt% of NR and 5 wt% of Alumina Trihydrate (ATH) provided promising results in resisting PD activities. However, as the NR content increased, more micropores existed, thus resulting in increased PD activities within the samples.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.9
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• pp.671-682
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• 1998

Chemical structure and electrical characteristics of 5 commercial crosslinked polyethylenes (XLPE) used as insulating materials for medium voltage distribution power cables in Korea were investigated. It was found that each XLPE shows different properties depending on the type of XLPE. Chemical structural irregularities of pellets change considerably by crossliking reaction, with some irregularities being disappeared after crosslikeng reaction. It was also found through a solvent extraction study that additives such as crosslinking agent and antioxidants act as major source retarding water tree growth. Low molecular weight polyethylene chains plays a different role in water tree growth of XLPE.

• JOURNAL OF ELECTRICAL WORLD
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• s.451
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• pp.46-58
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• 2014

At the end of 2013, there were 434 nuclear power reactors in operation worldwide, with a total capacity of 371.6 GW(e), approximately 80 % had been in service 20 years and more. Many Member States have given high priority to licensing their nuclear power plants to operate for terms longer than the time frame originally anticipated(e.g. 30 or 40 years). One of challenges for long term operation is cable ageing management. How can qualify the existing cable under harsh environment in nuclear power plant? The paper described the approaches on qualification, condition monitoring, and management of low voltage cables in nuclear power plant.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.6
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• pp.9-17
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• 2006

In this paper, we analyzed and measured the characteristics of the ballasts for HID lamps according to the cable properties. The ignition voltage and the steady state voltage and current are depend on the feature and the length of the cables. So we measured characteristics at 25[m] and 100[m] distances used by a low frequency electronic ballast a high frequency electronic ballast and a magnetic ballast. By measured and analyzed result of characteristics for various kinds of ballast and cables, we concluded that the electronic ballast driving with the low frequency is better than my other ballasts, and that the capacitance between the cables is important.

• JOURNAL OF ELECTRICAL WORLD
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• s.452
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• pp.22-28
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• 2014

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.56 no.4
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• pp.195-200
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• 2007

This paper describes the countermeasures for preventing the electric shock which can be occurred in the low-voltage handhole underwater. Low-voltage handholes were designed and made for the test in the testing field. Which were installed 4 cases. a metal handhole cover was employed in case 1; FRP(Fiber glass Reinforced Plastic) handhole cover in case 2; an insulated rubber was put on the joint of the cables in case 3; the exposed conductors(cover, frame etc) were commoned and grounded in case 4. Thus, an ground potential near the low-voltage handhole was measured and evaluated quantitatively for the 4 cases. The measured results show that the potential of case 2.3 were lower than that of case 1 because the insulated rubber and the FRP cover prevented direct contact to the fault point. The case 4 is the lowest among the 4 cases because the common and grounding helps the fault current release into the ground, which makes the ground potential rise lower. As a result, although each case has the defects, these ways can effectively lower the electric shock risk in the low-voltage handhole.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.4
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• pp.28-34
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• 2012

Installing surge protection devices for a low-voltage system is important to ensure the survival of electric or electronic devices and systems. If surge protection devices (SPD) are installed without consideration of the concept of lightning protection zones, the equipment to be protected might be damaged despite the correct energy coordination of SPDs. This damage is induced by the reflection phenomena on the cable connecting an external SPD and the load protected. These reflection phenomena depend on the characteristics of the output of the external SPD, the input of the loads, and the cables between the load and the external SPD. Therefore, the SPD has an effective protection distance under the condition of the specific load and the specific voltage protection level of SPD. In this paper, PSCAD/EMTDC software is used to simulate the residual voltage characteristics of SPD Entering the low-voltage device. And by applying a certain voltage level, the effective protection distances of SPD were analyzed according to the each load and length of connecting cable, and the effectiveness of SPD were verified.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2326-2328
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• 1999

Developments of effective and economic diagnostic apparatus for industrial plastic insulated high voltage power cables are in discontented condition still. Some report told that DC high voltage was damaged plastic insulation of a partially aged power cable to lead breakdown easily. But now, we have no alternative tools of DC diagnostic apparatus, and we try to reduce a possibility of hazard DC diagnosis. DC diagnostic apparatus still have many advantages to field cable engineer like low price, portability easy applications and sufficient data. Main hazard of DC diagnosis is excessive hight of applied voltage Recent developments for DC diagnosis use considerably low voltage. But new test methods need special measuring device and manipulator, like high input impedance voltmeter, low leakage current high voltage switches, etc. So that reason, new DC diagnostic devices are normally very expensive and have low efficiency, economically. We try to design a composite test device for 3$\sim$4 newly developed method, have economical benefit th industrial engineer.