• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.573-575
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• 2005

In the steel industry, a steel melting electric arc furnace is used to produce both carbon and alloy steels. Steel scrap which is charged into the furnace is heated by means of electric arc between graphite electrodes and the scrap. In this melting process, current is supplied to the furnace through HCC(high current cable) which connect the furnace and transformer. Four HCCs are assigned to each phase in our system to divide the current. Since a sudden cable breaking result in the shutdown of melting process, an aging detection of HCC is very important for both an improvement of productivity and cost reduction. In this paper, the aging of the HCC is estimated by using the current ratio between four HCCs.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1801-1803
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• 1996

This paper describes a diagnosis of cable splices by analysis of ultrasonic signals which is generated by partial discharge. Peak-peak amplitude of ultrasonic signals was used to diagnose cable splices. It is proposed that aging discrimination is possible by analysis of ultrasonic signals in cable splices.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.6
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• pp.187-193
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• 2018

There has been a gradual increase in the demand for the electric power in Korea. In order to meet the demand, power station should have technical functions with increased effectiveness. When accident happens in electric machinery at power stations, huge amount of economic losses and mulfunction of equipments occur. One of the accidents is a deteriorated cables operating power stations. In order to prevent cable accident in advance, we should monitor the insulation status of the cable. Cable accidents are resulting from the junctions. We have developed and installed a device in order to identify the status of junction part of power cable at Korea Western Power Co., Ltd.. We performed an accurate diagnosis for the stable utilization of junctions where the accidents occurs most frequently, and to increase the reliability. In this paper, we present the concepts of our device and the method of monitoring diagnosis for the stable use of junctions at cables predicting the life time of cables by analyzing the data obtained by the device. We also present the hardware aspect of the device we have developed.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1996.11a
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• pp.122-124
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• 1996

This paper describes a diagnosis of distribution cable splices by analysis of ultrasonic signals which are generated by partial discharge. A method of ultrasonic signal was used to detect internal defects in distribution cable splices. It is possible that analysis of ultrasonic signal predicts failure by partial discharge generated in distribution cable splices.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.05a
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• pp.46-49
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• 1994

In order to investigate possibility of CV cable diagnosis technique, residual insulation characteristics of .long - term serviced 0.6 kV CV Cable are examined by DC leakage current residual voltage tensile strength, cross1inking density and AC & impulse breakdown. Also effect of cable structure and water tree are reported

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.8
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• pp.1632-1638
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• 2011

Electric cables are one of the most important components in a nuclear power plant since they provide the power needed to operate electrical equipment. Despite their importance, cables typically receive little attention since they are considered passive, long-lived components that have been very reliable over the years when subjected to the environmental conditions for which they were designed. The operating experience reveals that a defect of the insulator or poor construction causes the initial failure of cable. However, the number of cable failures increase with plant aging, and these cable failures are occurring within the plants' 40-year licensed period. These cable failures have resulted in plant transients, shutdown, loss of safety functions or redundancy, entries into limiting conditions for operation, and challenges for plant operators. Therefore, diagnosis of MV cable installed in NPPs has become one of the most urgent issues in recent years. In accordance with PSR, condition maintenance for cables is also continuously required. Recently, HFPD tests have been widely performed to diagnose cable in the transmission and distribution cable system. However, on-line HFPD wasn't used in the NPPs because of the danger of plant shutdown, measurement sensitivity and application problems, etc. In this paper, HFPD measurement with portable device was performed to evaluate the integrity of the 4.16kV & 13.8kV cable lines. The test results show that HFPD is highly attractive to the diagnosis of MV cables in NPP by high detection sensitivity on-site.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.10
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• pp.699-703
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• 1999

An experimental study to identify the energized status of the 22.9kV underground power cable by the detection of vibration has been performed. We have derived that there exists vibration at double the line frequency in live cables by electromagnetic force. The relative amplitudes of the cable vibration according to the energized status of the cable were calculated by computer simulation. The cable vibration can also be picked up by accelerometer. A prototype was tested on the underground distribution system in Chonan substation, KEPCO. Comparison between simulation results and field test results was performed. The results showed that the energized status of the calble can be identified by measuring the vibration of the cable using accelerometer.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.11a
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• pp.235-239
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• 2008

Cable systems are a construction of elements carrying only tension and no compression or bending in membrane structure. Tensile membrane structures are most often used as roofs as they can economically and attractively span large distances. But cable systems have weaknesses to vibration by earthquake, wind and vehicle loads. Damage detection of cable systems by using existing safety diagnosis is difficult to detect the characteristic change of overall structural action. If cable snaps are occurred to cable release and tear in tension structures, these are set up a vibration. So, we used piezo-electric materials, and The principle of operation of a piezoelectric sensor is that a physical dimension, transformed into a force, acts on two opposing faces of the sensing element. In this study, the development on test method of cable system is proposed and tested by tensile strength using piezo-electric materials.

• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.23-25
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• 2004

HFPD(High Frequency Partial Discharge) measurement has been widely performed to diagnose cable system in the world. Shin-Yeongdeungpo 345kV XLPE line was successfully diagnosed by PD measurement methode last year. Moreover, aged power cable lines which were installed 15 years ago have been tested from this year. In this paper, the result of PD diagnosis for aged 154kV cable line is reported. The PD pattern from TMJ which was monitored by PD measurement system for several days showed typical void pattern. The joint was replaced and voids between semi-conductor layer and insulating layer in the joint was founded.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.6
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• pp.78-84
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• 2000

In this paper, the diagnosis technique was proposed by measuring and analyzing ultrasonic signals caused by partial discharge on the interface of cable joint. The measured ultrasonic signal was filtered by wavelet transform, and then the dominant signal of filtered signal was analyzed by fast fourier transform(FFT). As a result, it was confirmed that different characteristics were obtained with the moisture and the metal powder on the interface of cable joint and with voltage increment.