• The Journal of the Korea institute of electronic communication sciences
• /
• v.6 no.2
• /
• pp.262-267
• /
• 2011

In the power system, the transformer's neutral earth reactor line 1 grounding failure may occur. By limiting the magnitude of the failure grounding current flow, it will aid to reduce the failure of the transformer. Consequently, this also may avoid the failure of the disconnection of the industrial insulator line that cause by melting. Besides, utilizing the decreasing circuit breaker or others related equipment can use to avoid the possibility of explosion of the transformer. If the failure happen during the operation of the power system, a huge interference will definitely may occur. Therefore, by installing the DONGBUSAN S/S #3M.Tr neutral earth reactor among TOP and BOTTOM BRACE part in the power system, the causes of the rising temperature and reason of the over-current flow that cause by over-current can be analyze.

• Smart Media Journal
• /
• v.9 no.1
• /
• pp.38-44
• /
• 2020

Due to the high dependence on electric energy, electric fires make up a significant portion of fires in Korea. Electric arcs by short circuits or poor contact cause three of four electrical fires. An electric arc is a discharge phenomenon of electrical current between the insulators, which instantaneously produces high temperature. In order to reduce the fire due to electric arc, this study aims to predict the electric arc risk. We collected arc data from the arc detectors and converted into graphs based on temporal arc data. We used machine learning for training converted graph with different number of temporal arc data. To measure the performance of the learning model, we use the test data. In the results, when the number of temporal arc data was 20, the prediction rate was high as 86%.

• Journal of the Korean Society for Railway
• /
• v.19 no.4
• /
• pp.468-479
• /
• 2016

In order to supply power to online monitoring systems that are attached to high voltage catenary or overhead wires, a wireless power transfer system is required that is able to transmit power over the insulation gap. Such wireless power transfer systems have transmitter and receiver coils that have diameters of over 10cm. This paper focused on an investigation of the sources of loss in the coils when the coils are fabricated using printed circuit board technology. Using finite element simulation results, it has been shown that the dielectric loss in the substrate was the dominant source of the total loss. It has been demonstrated that the selection of a proper dielectric material was the most critical factor in reducing the loss. For further reduction of the loss, the distributed tuning capacitor method and the slotting of the inter-turn spaces have been proposed. For the evaluation of the proposed methods, four coils have been fabricated and their equivalent series resistances and quality factors were measured. Measured quality factors were greater than 300, which means that these devices will be helpful in achieving high coil-to-coil efficiency.

• Fire Science and Engineering
• /
• v.16 no.1
• /
• pp.18-23
• /
• 2002

Efficiency estimation of toxicity free resistance cable experiments were conducts to understand toxicity free fire ersistance polyolefin insulation material and smoke density characteristic and combustion gas corrosion analysis. A main cause of fire-growth and generating toxic gas when it burns, should be dealt with great care in life safety design. Similar patterned fire incidents such as, Inchon Live-Hof Pub Restaurant as, Sea-land Children Resort have proven that serious loss of lives were caused by hazardous gas generated fire resistance cable materials. In this paper, Referenced documents were ASTM E662 standard test method for specific Ds genalated by solid materials. The furnace control system shall maintain the required irradiance level under steady-state condition with the chamber door closed of 2.5$\pm40.04〔w/$\textrm{cm}^2$〕for 20 min. According to the results of the smoke density analysis of NFR-8 and FR-PVC the highest decomposition flaming smoke density range of NFR-8 and FR-PVC were 25.2 to 37.5 and 51.1 respectively. Nonflaming smoke density range of NFR-8 and FR-PVC were 100.4 to 112.2 and 126.5 to 398.8. Also, the fire gases was occurred carbon monoxide and decomposition than in polyolefin due to incomplete combustion of PVC which has high content of carbon in chemical compound.