• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1626-1628
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• 2003

The lightning arrester is a very important overvoltage protection device in the electric power system. Therefore, the inspection of lightning arrester whether it keeps its performance or not properly has close related to verifying the safety confidence of the electric power system. But the development of the deterioration measuring method and on-line detecting system, is necessary to monitor the deterioration of the lightening arrestor. In this paper, we developed the lightning arrester degradation monitoring system. This system detected leakage current of lightning arrester by using the ZCT, and analyze the third harmonics ingredient of leakage current using DFT method in the Data Acquisition Unit(DAU). The analyzed current signal is transmit to the Human-Machine Interface(HMI), and HMI alarmed when accident are occurred and informed with the amplitude of leakage current to the operator.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.513-514
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• 2006

This paper presents the temperature characteristics with the structure of 18 kV surge arresters for distribution system. Three types of polymer arrester were fabricated and a ceramic arrester was also prepared to investigate. Below $100^{\circ}C$, three types of polymeric arresters exhibited almost the same leakage current value, but above $100^{\circ}C$, the polymeric arresters whose module was injected into polymeric housing with the grease exhibited the highest leakage current. In contrary, the arresters being manufactured by directly injecting silicone rubber onto arrester module exhibited the lowest leakage current. The rapid rising of leakage current of the polymeric arresters with the grease at $120^{\circ}C$ was because of the deterioration of the insulation characteristics of the grease between the FRP module and the silicone housing. All polymeric arresters exhibited the same surface temperature characteristics but the ceramic arresters was slower than the polymer arrester in heat emission despite the lowest leakage current. It was thought that the air layer between ZnO varistor blocks and the ceramic housing prevented the heat emission.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.11
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• pp.493-497
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• 2005

This paper dealt with the influence of harmonic voltages on arrester diagnostics and its compensation method by using a designed Pspice arrester model. A pure sinusoidal voltage and its 3$^{rd}$ harmonic voltage were applied to the model, and the leakage current components were analyzed. The simulation results have shown that the peak value of resistive leakage current depends not only on the phase of the 3$^{rd}$ harmonic voltage but also on the magnitude of it. In this paper, an approximated 5$^{th}$ order polynomial formula by the Least-Square-Technique was derived, and correction factors which compensate the error caused by the 3$^{rd}$ harmonic voltage were calculated.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.443-445
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• 2000

This paper describes the assessment of proper location of lightning arrester in combined transmission line which is connected with overhead line and underground cable. The modeling for simulation is established using the actual system in ATP Draw and EMTP. Simulation is carried out to find out the best point to install the arrester in given the model system. And also voltage and current is analyzed on cable covering protection unit(CCPU). The simulation result demonstrated the best location of arrester in the given transmission line through the detailed analysis and its assessment.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.1422-1424
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• 2004

Various deterioration diagnostic techniques and devices are suggested, and most of which measure leakage current components as an indicator of arrester ageing. However, the techniques based on the magnitude of leakage current measure simply RMS or peak value of leakage current components and do not provide detailed information needed in the diagnosis. In this study, we found that the phase vs. wave height of total leakage current is changed or a new wave height is produced with arrester ageing. To complete the new technique, we designed an arrester diagnostic device which is composed of a current detection circuit, an optical transmission circuit, and an analysis program. After measurement of the total leakage current, magnitudes, phase vs. wave height, and harmonics of the leakage current components are analyzed by the microprocessor based device. From the experimental results, we confirmed that the device can measure most parameters needed for the arrester diagnostics and analyze an initial deterioration state.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.5
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• pp.117-124
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• 2016

In this paper, we developed a breather valve with a water mist system for use near an oil storage tank. Our process applied a water mist system to the flame arrester to evaluate the fire suppression characteristics. For the fire suppression evaluation of the water mist system, we evaluated the angle of the nozzle, fire suppression, spray particle size, flashback, fire suppression time, and fire suppression test of antifreeze. Through the fire suppression test, the best fire suppression nozzle used an angle of $140^{\circ}$, and the flashback phenomenon of flame arrester did not occur. The fire suppression time of water mist system time was within three seconds, and the antifreeze was no problem with the fire suppression.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.367-369
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• 1997

The process of designing protective circuits for signal lines usually consists of a time-consuming trial-and-error procedure, which also requires expensive equipment. However, computer simulation can drastically reduce the costs and time of design procedures based on experimental validation. In this study a gas arrester Pspice-model considering the response time characteristics is presented. The effects of various waveforms on the transient behaviors and firing voltages of a gas arrester were modeled by controlled voltage source E and TABLE function of PSpice, respectively. To estimate the characteristics of the gas arrester model proposed, three different voltage waveforms were used in the simulation and the measurement. The results of the computer simulation are in Rood agreement with the results of the experimental analysis.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.3
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• pp.497-502
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• 2012

Power line communication(PLC) is a kind of communication technology, was made use of controling a frequency narrow band, but as the PLC technology developing, in the near future get to the commercial step that is broadband PLC upto 30 MHz. This paper deals with the PLC of electric railway using capacitive signal coupler. An AC arrester for catenary is used as a capacitive signal coupler, has the characteristic of capacitor. As a result of field test, a messenger wire used PLC contain much of conducted noise about overall frequency band and also signal attenuation rate increased with increasing frequency between two points. and the communication speed of PLC used messenger wire is 793kbps at a distance of 40m. Experimental results show the possibility of PLC using a messenger wire and an AC arrester for catenary at electric railway.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.458-460
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• 2001

This paper described the unbalanced voltage on the tertiary bus of a single Phase auto transformer in the case of parallel operation with different manufacturer at each Phase. The unbalanced capacitances between primary to secondary winding, secondary to tertiary winding and primary to tertiary winding makes unbalanced bus voltage in the tertiary bus side. The unbalanced voltage let the surge arrester to operate in the power frequency range, and it causes the arrester to burn out. The failure of the arrester at one phase makes line to ground fault, which lead to the surge arrester failure of the other two phase on the tertiary bus.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.8
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• pp.361-364
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• 2005

In this paper, surface temperatures of ZnO arresters as a function of ambient temperatures and leakage currents were experimentally investigated. The variations of the leakage current was below 10 uA, which comes about $4.5\%$ of the normal leakage current. Temperature differences between the ambient and the surface of arresters were not shown until $150\%$ to the normal leakage current, and were remarkable over $200\%$. From the results, we deduced a couple of polynomials which enables the calculation of the leakage current by the measurement of surface temperature. Tests on used arresters have shown the same results as the experimental one. Also, we expect that an arrester diagnosis is possible by measuring the surface temperature of them after more studies on the effect of wind, moisture penetration, and arrester types.