• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.1
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• pp.132-137
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• 2006

The second part of paper related rotor failure is to evaluate that the axial magnetic flux measurement could be used as a tool of the condition monitoring system for the induction motor and to develope the diagnostic algorithm for the various fault in the electric motors. The magnetic leakage flux signal is captured by the flux coil located at the end of motor without the disturbance of the operation. And the signal is analyzed both time and frequency domain to detect the failure of the motor. Specific signature can be described in tin and frequency domain for each fault of the motor. The experimental test found that the rotor failures - broken rotor bar, broken end ing and rotor eccentricity, could be detected from the spectrum with high resolution. The method of detecting the rotor fault was found by analysing the specific frequency and the sideband of the rotor bar pass frequency from axial leakage flux spectrum. In addition the optimal flux coil and measuring equipment for the axial leakage flux measurement was verified and the diagnostic method for the detection of the rotor related failure was developed.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.1
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• pp.61-68
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• 2018

Recently, concentration of fine and ultra-fine particulate matter(PM) has been increased in KOREA. The increase of PM in KOREA is due to increase of domestic industries and yellow dust from china. PM is known to cause diseases such as dyspnoea, asthma, arrhythmia. Since PM is harmful to human, KOREA Ministry of Environment(ME) warns people to stay indoors when the outdoor PM concentration is high. However, prior studies has shown that indoor PM concentration can be relatively high when outdoor PM concentration is high due to infiltration of PM into buildings though leakage areas. In this study, airtightness, indoor and outdoor pressure difference and PM 2.5 & 10 concentration were measured in an apartment complex to observe PM infiltrating into building. Field measurement was conducted in newly-built apartment buildings to avoid the influence of indoor PM which can be generated by residents. The airtightness test was conducted to identify the leakage areas of the apartment, such as electric outlets and supply/exhaust diffusers. The airtightness test result showed that the air leakage area of the building was dominant in buildings envelop. According to indoor and outdoor pressure difference measurement result and PM concentration measurement result, it can be concluded that outdoor PM can infiltrate into indoor by leakage areas when wind is blown toward the apartment. As a result, pressure difference formed by the external weather condition and architectural characteristics such as the airtightness in building can influence PM to infiltrate into buildings. In further studies, I/O ratio, stack-effect, infiltration and penetration factor will be considered.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.515-516
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• 2006

The resistive leakage current is an important parameter for arrester diagnosis. However, the 3rd harmonic leakage current is more widely used than the resistive one because of its easy measurement. In this paper, we studied the correlation between the resistive and the $3^{rd}$ harmonic leakage current of ZnO arresters. The resistive leakage current was measured according to the IEC 60099-5 in AC applied voltage. The $3^{rd}$ harmonic leakage current was analyzed by using a designed band-pass filter having 180 [Hz]-center frequency and 10 [Hz]-bandwidth. The experimental results show that the $3^{rd}$ harmonic leakage current changes proportionally with the resistive leakage current variation under the maximum continuous operating voltage (MCOV).

• Journal of Korean Society of Water and Wastewater
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• v.19 no.1
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• pp.8-15
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• 2005

Field measurement data on water leakage are not readily available and it causes inaccurate assessment of water demand and poor supply planning. In this study, the procedure for leakage detection and unaccounted water calculation is proposed and applied to a city. The city has suffered from the significant amount of leak water and the financial loss as a result. Measurements were made for pressure and flow at 18 locations before and after the repair. Repair of the leakage increased pressure up to $2.0kgf/cm^2$ and saved 17.1% of water supply from distribution reservoirs. Monetary value of annual water savings for the entire city amounts to 1 billion won. It is believed that leakage detection and data analysis conducted in this study will contribute to the change of current practice and to the establishment of better water supply management system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.88-91
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• 2001

Our knowledge about their long-term performance in an outdoor environment is still very limited. The electrical stress caused the surface of these insulators to become degradation. In order to evaluate leakage current patterns caused by surface aging on polymeric insulators, we utilized the combined aging test facility and leakage current monitoring system. And we get the continuous leakage current values from each sample. After completing the 3000h combined aging cycle test, leakage current measurement were conducted for these samples and carried out harmonics analysis for its data.

• 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.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.2
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• pp.62-67
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• 2002

This paper provides the results of accelerated aging test of 18kV ZnO lightning arresters to investigate the leakage current characteristics. It was impossible to establish the replacement criterion for field operating lightning arrester because conventional aging test was only focused on the aging of ZnO elements. In general, it is possible to replace the aged arresters before the failure in the field using the leakage current measurement because it must be increased by the aging. But we can not use the method because we don't know the characteristics of the installed lightning arresters. Therefore in this paper we applied operating voltage and accelerating cycle which consists of temperature and humidity to the arresters. Then we measured the variation of total and resistive leakage current and found out the characteristics of the acted lightning arresters.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.2068-2069
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• 2007

This study describes a compairison leakage current properties between a polluted insulator and insulator subjected to salt polluted condition. Exposure tests at a sea coast test and the leakage current of insulators, climate conditions, and salt deposit density were measured during the tests. Appearance of leakage current for the insulator was affected by the humidity and the salt deposition on the surface. comparison of leakage current under salt polluted conditions. salt polluted test and humidity tests were carried out in laboratory using the same insulator profiles in oder to determine the leakage current patterns during critical conditions

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.7
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• pp.47-56
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• 2010

Faults due to salt damage prevent the provision of stable power supply because they affect large areas and require much time and man power for recovery. Korea, three sides of which are surrounded by sea, is especially exposed to the impact of sea winds and typhoons. Therefore, salt damage to power facilities is one of the greatest problems of Korea's power system. To prevent salt damage pollution of insulators, the salt damage deposit on the insulators is regularly measured, and the insulators are washed when their salt damage deposits are expected to reach a critical level. When salt is detected on the insulators, however, errors are likely to occur according to different workers and environments. Therefore, a leakage current measurement method was proposed in this study to check the salt damage pollution level and reduce these errors.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.801-802
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• 1992

Poly Si TFTs have been fabricated from low temperature annealed a-Si films. I-V and C-V characteristics in the off-state region were measured. Analytical model for the leakage current in the off-state was suggested. In the measurement, capacitance increased abruptly with Increasing gate and drain voltage. This phenomena is attributed to the leakage current.