• 한국전기전자재료학회논문지
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• 제11권12호
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• pp.1055-1059
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• 1998

The correlation between the propagation of electrical tree and distributions of partial discharge(PD) pulses accompanying with electrical tree of bush type in low density polyethylene were discussed. We measured the growth of electrical tree by using optical microscope and PD data simultaneously. The PD data detected and analyzed were PD magnitude, repetition rate, average discharge power, average phase angle, and $\psi$-q-n distribution pattern. The average discharge power and repetition rate of PD had good linear relation with area of tree. Repetition rate and peak discharge magnitude and width of discharge phase angle increased with the tree.

• 대한전기학회논문지
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• 제45권3호
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• pp.432-437
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• 1996

This paper describes a diagnostic technique of power transformers by on-line detection of ultrasonic signals. A trend of partial discharge variation in a real transformer was estimated by counting the number of ultrasonic signals until insulation paper in the point-to-plane electrode is punctured. The number of electrical signals is closely related to the ultrasonic signals generated by partial discharge. The trend of the ultrasonic signal number could easily be distinguished by taking moving average. The insulation failure due to partial discharge in transformers can be predicted based on the trend analysis of ultrasonic signal number caused by partial discharge. (author). 14 refs., 10 figs.

• 한국전기전자재료학회논문지
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• 제20권9호
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• pp.780-786
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• 2007

This paper describes the influence on partial discharge characteristics of defects at the model XLPE/EPDM interfaces of power cable joints. The defects of void and copper which could inadvertently be present at the joint interface. We measured ${\Phi}-n,\;{\Phi}-q$ patterns by a computer-aided partial discharge measuring system. Several parameters i, e, maximum discharge $q_{max}$ [pC], average discharge q [pC/cycle], and average angle of discharge ${\Theta}g$ [deg] were found to depend upon the defect type varying applied voltage. As the result of time evaluation, partial discharges are small different at copper defects, but is decreasing obviously about 20 minutes at void defect. It considered that difference of magnitude of total positive discharge of Q+ [pC] and total negative discharge of Q- [pC] is SPMD(swarming pulsive micro discharges).

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 D
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• pp.1624-1626
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• 1999

PD in defect of solid insulation system is very harmful since It often leads to deterioration of insulation by the combined action of the discharge ions bombarding the surface and the action of chemical compounds that are formed by the discharge. PD can indicate incipient failure, so it has been used to determine degradation of insulation. In this paper. we investigated PD in defects of solid insulation by using statical method and classified PD patterns with surface discharge, electrical tree and void discharge by using Kohonen network. we used peak charge, average discharge power, average discharge current, repetition rate, skewness, kurtosis, QN of the max pulse height vs. repetition rate $H_q(n)$ for analysis and classification.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.234-238
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• 1999

The correlation between shape of electrical trees and partial discharge(PD) pulses in low density polyethylene(LDPE) were discussed. We observed growth feature of electrical tree by using optical microscope. On the basis of experimental results of measurements of trees occurring in the needle-plane arrangement with needle shape void and without needle shape void , statistical quantities are derived, which are relevant to PD pulse amplitude and phase. The PD quantities detected by partial discharge detector. we were analyzed q-n distribution pattern and $\psi$ -q-n distribution pattern. In this experiment, electrical trees in the needle-plane arrangement with needle shape void propagated branch type tree and in the needle-plane arrangement without needle shape void propagated bush type tree

• 신재생에너지
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• 제4권2호
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• pp.94-104
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• 2008

The change of water discharge capability of sluice caisson for tidal power plant according to installation of the rubble mound was investigated by performing laboratory experiment. The experiment was carried out in an open channel flume with a great care to measure flow rate and water level in the flume accurately. Eight different sluice caisson models were used in the experiment. The water discharge capabilities of seven sluice models decreased with respect to the placement of the rubble mound, while increased for only one sluice model. On average, the values of discharge coefficient decreased by approximately 10% when the sluice models were placed on the rubble mound. It is concluded that the shape of the rubble mound can affect the water discharge capability of the sluice caisson, so that its shape should be significantly considered in the design of the sluice caisson, especially when it is deployed in a site of relatively deeper depth.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2009년도 학술발표회 초록집
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• pp.1311-1315
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• 2009

Understanding of the hydraulics of flow is very important to support the management of river. The cross-sectional area, average velocity, flow depth and discharge can be regarded as a power function each other. In this paper the flow of Bocheong stream basin is experimentally studied. The correlation analysis was performed between observed hydraulic factors by the power type function. The constants resulted from the correlation analysis were calculated by the geomorphologic characteristics of the watershed using the power type function. The correlation coefficients between the hydraulic factors were appeared close to unit having strong correlationship. The two conditions of equality of the continuity equation were analysed, and the conditions were found to be good results. From these results the observed hydraulic data of Bocheong stream basin can be concluded as a reliable data. The correlation coefficients between the parameters of the hydraulic characteristics and geomorphologic factors were found to be close to unit.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.506-509
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• 2003

In this paper, the $\Phi$-q-n pattern and average discharge power of silicone rubber have investigated effect of inter impurities. It's changed impurities by silicone oil, water and copper. Applied voltage is AC 3, 4, 4.5, 5, 5.5[kV]. And data acquisition time is 10 second(600 cycles). These results suggest that partial discharge(PD) is shower negative polar than positive polar at 3[kV]. Positive polar's PD value increased with increase of applied voltage. The Conductivities expressed same $\Phi$-q-n pattern in positive polar and negative polar at phase region.

• 전기학회논문지
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• 제62권9호
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• pp.1297-1301
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• 2013

This paper analyzes of PD occurrence position through an analysis of the arrival time difference between the GIS partial discharge signal. Because of GIS (Gas Insulated Switchgear) is a facility very important power equipment and as part of the equipment that make up the power system, the stabilization of the power industry, which accounted for 88.5% share of GIS substation in the form of a substation is an important equipment for power supply. In the situation where we are gradually expanding the need for preventive diagnosis in order to improve the efficiency of equipment management and failure prevention for Preventive diagnosis. In this paper as a method for extracting pre-defect of failure of GIS Apply the average value method of calculating the 5 times each using a pulse of the first time of the second pulse (${\Delta}t$) with an oscilloscope generation position PD(Partial Discharge). the results of GIS internal inspection, the partial discharge of the actual the position of the partial discharge was confirmed with an accuracy of about 82% of positions. Arrival time difference in the most effective manner if the partial discharge of GIS internal occurs by applying the averaging method and TOA(Time of arrival) method, the partial discharge occurs you through the measurement and analysis of PD signal occurs was confirmed in the experiment are presented and diagnostic methods location tracking.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.456-458
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• 1995

This paper describes a diagnosis of power transformers by on-line detection of ultrasonic signals. Partial discharge in power transformer generates ultrasonic signals. The trend of the ultrasonic signal number can be measured when partial discharge is generated in HV Winding. The trend of the ultrasonic signal number could easily be distinguished by taking moving average. The insulation failure due to partial discharge in transformers can be predicted based in the trend analysis of the number of ultrasonic signals caused by partial discharge.