• Journal of the Korea Safety Management & Science
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• v.23 no.4
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• pp.23-29
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• 2021

The purpose of this study is to reduce the probability of occurrence of electric fires as a preemptive preventive measure, and to strengthen the capability of preventing electric fires by strengthening the cooperative function between electric fire-related departments and establishing a cooperative system. In this study, the general aspects of electric fires were identified by reviewing the literature such as ignition mechanisms of electric fires. And the major electrical fires that occurred in the last 10 years were classified into ignition factors (short circuit, overload/overcurrent, and earth leakage/ground fault) and ignition sources (wiring/wiring appliances, electrical equipment/household appliances). And the 4M technique was used to analyze the potential causes of ignition at the fire site and to suggest preventive measures. In the case In this study, out of 48 electrical fires in the past 10 years, 16 short-circuit fires, 3 overload/overcurrent fires, 3 short-circuit and earth fault fires, 16 fires in wiring/wiring appliances, and 10 fires in electrical equipment/home appliances classified as cases. And prevention measures were presented in terms of human, machine, media, and management by using the 4M technique. For the preemptive prevention of electric fires, strengthening the compulsory electrical safety inspection and making it mandatory to report when new or expanding electric facilities, charging a fee for electric safety inspection for detached houses and granting benefits subject to inspection completion, improvement of the electric safety voluntary inspection table and safety indications; It was suggested as a policy to organize and operate electrical safety inspection personnel in a two-person team (mixed), establish a close work cooperation system with related organizations, and strengthen electrical safety education and publicity.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.110-112
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• 2005

Recently, the reactor trip in nuclear power plants has mostly occurred by the failure of secondary electrical facilities. Some kinds of technical standards or acceptable criteria are required to regulate those facilities. Therefore, in this paper the failures of secondary electrical facilities which cause reactor trip are analyzed, and the inspection technologies including guidelines for secondary electrical facilities are developed.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.1240-1242
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• 1996

In a still mill, the effective surface defect inspection algorithm is necessary. For this purpose, this paper proposed the preprocessing algorithm for surface defect inspection of cold mill strip. This consists of live steps. They are edge detection, binarizing, noise deletion, combining of fragmented defect and selecting the largest defect. Especially, binarizing is a critical problem. Bemuse the performance of the preprocessing is largely depend on the binarized image. So, we develope the adaptive thresholding method, which is multilevel thresholding. The thresholding value is varied according to the mean graylevel value of each test image. To investigate the performance of the proposed algorithm, we classified the detected defect using neural network. The test image is 20 defect images captured at German Sick Co. This algorithm is proved to have good property in cold mill strip surface inspection.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1008-1010
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• 2005

In the examination of steam generator(SG) tube in nuclear power plant, eddy current testing probes play an important role in detecting the defects. Bobbin probe and MRPC probe is usually used for the inspection of SG tube. Bobbin probe is good at high speed inspection, but ability of detection of circumferential defect is very weak. On the contrary MRPC probe, which moves for inspection in the direction of axial and circumferential simultaneously, has very slow inspection speed, but it has excellent detection capability for small cracks, which is hardly detected by bobbin probe. In this paper, for the accurate analysis of experimental ECT signals, construction of MRPC probe signals database according to the variation of defect size is the main purpose. Using 3-D finite element method, ECT signals are analyzed, and signals analysis add according to frequency ingredient. The results, which are analysis and characteristics ion of electromagnetism simulation signals, is databased.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.10
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• pp.101-107
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• 2007

In order to introduce remote monitoring system for effective safety management of electrical facilities for general use, which the most of electrical fires and non-inspection problems due to absence are generated development of local device model considering cost and installation is requested. This paper presents local device models for remote electrical safety inspection of electrical facilities for general use and in order to rational model according to installation place of electrical facilities for general use, compare and analysis cost, installation and communication method of local device models. The results show that rational model for remote safety inspection of electrical facilities located in houses, which occupy the must of electrical facilities for general use, is to give safety monitoring ability to low voltage remote meter reading(or automatic meter reading: AMR).

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.1
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• pp.89-95
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• 2010

A new live-line insulator tester was developed to detect faulty insulators in 154kV power transmission lines. This paper is the second part of the two-part paper and deals with its inspection algorithm development. Unlike normal condition with low pollution and low humidity, the inspection data measured in the field under high pollution or high humidity showed that the voltage distribution of an insulator string has offsets in comparison with those of others and its insulation resistances are greatly decreased, which leads to wrong results of the existing inspection algorithms under such conditions. To solve this problem, we propose new diagnosis algorithms that can exactly detect faulty insulators from measured data regardless of environmental conditions. Its effectiveness was validated by live-line field tests in actual power lines.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.3
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• pp.95-101
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• 2000

In this paper, an improved method for magnetic inspection to detect surface of a conductor is presented. The presented method is based on the technique of ECP(Electric Current Perturbation), which is to measure the variation of current flow due to defects with a magnetic sensor. The inspection performance is improved by using high frequency current behaviors in order to concentrate the current near the defect and employing the resonant frequency of a search coil as an operating frequency. By analytical results and experiments of the test specimens, the feasibility of the inspection method is shown.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.11-13
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• 2007

The appearance inspection of various electronic products and parts has been executed by the eyesight of human. But inspection by eyesight can't bring about uniform inspection result. Because the appearance inspection result by eyesight of human is changed by condition of physical and spirit of the checker. So machine vision inspection system is currently used to many appearance inspection fields instead of the checker. However the inspection result of machine vision is changed by the illumination of workplace. Therefore we have used a power-law transformation in this paper. for improvement of vision inspection accuracy and could increase inspection accuracy of vision system. Also this system has been developed only using PC, CCD Camera and Visual C++ for universal workplace.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.1
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• pp.142-147
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• 2018

Private electrical facilities are judged whether it is suitable for the insulation aging condition of their incoming underground cables using DC leakage current test method. In the case where the service point of utility is the secondary side of cut out switch installed in the electric pole, there is a problem that it is difficult to separate the lightning arresters(LA) because of their high position of the pole. Therefore, the field test voltage is applied at value lower than DC 30 kV, which are stated in the inspection guideline. However, this test could reduced the insulation performance of the LA by accelerating the electrical stress of the metal oxide varistor element in the pre-breakdown region. In this study, we analyzed the relationship between the DC test voltage and the leakage current using the non-destructive DC high voltage equipment with leakage current measurement function. The results show that the leakage current increases sharply above the specified test voltage. As a consequence, it could be contributed to improve insulation aging inspection method by selecting the possible test area on the VI characteristic curve of the pre-breakdown area of the LA.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.479-485
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• 2004

The purpose of this study is to develop a practical image inspection system that could recognize it correctly, endowing flexibility to the productive field, although the same object for work will be changed in the size and rotated. In this experiment, it selected a fighter, rotating the direction from $30^{\circ}\;to\;45^{\circ}$ simultaneously while changing the size from 1/4 to 1/16, as an object inspection without using another hardware for exclusive image processing. The invariant moments, Hu has suggested, was used as feature vector moment descriptor. As a result of the experiment the image inspection system developed from this research was operated in real-time regardless of the chance of size and rotation for the object inspection, and it maintained the correspondent rates steadily above from 94% to 96%. Accordingly, it is considered as the flexibility can be considerably endowed to the factory automation when the image inspection system developed from this research is applied to the productive field.