• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.6
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• pp.308-312
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• 2006

Partial Discharge (PD) phenomena occurred by different nature of insulating defects has been regarded as a random process by which Phase Resolved Partial Discharge Analysis(PRPDA) has been proposed and then commercially accepted for the diagnosis of the power apparatus since more than three decades. Moreover, for the same purpose, a novel approach based on the Chaotic Analysis(CAPD) has been proposed since 2000, in which Partial Discharge(PD) phenomena is suggested to be considered as a deterministic dynamical process. In this work, for the diagnosis of Gas Insulated Transformer(GITr), four different types of specimen were fabricated as a model of the possible defects that might possibly cause its sudden failures such as turn to turn insulation, inter coil insulation, free moving particle and protrusion. For this purpose, these defects are introduced into the Gas Insulated Transformer(GITr) mock-up and experimental investigations have been carried out in order to analyze the related Partial Discharge(PD) patterns by means of both Phase Resolved Partial Discharge Analysis(PRPDA) and Chaotic Analysis(CAPD) respectively and then their comparisons are made systematically.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.8
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• pp.354-360
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• 2002

The partial discharge detecting method using the ultrasonic technique has been investigated to monitor the insulation ageing of a transformer. However, the result of the studies on the ultrasonic technique for detecting of partial discharge in the operating transformer is not enough yet to utilize. This paper presents the analysis of the ultrasonic signals due to the partial discharge in a model transformer and the corona in air at a shielded high voltage room. In addition, the ultrasonic signals due to the vibration from the core, operation of the cooling pump, the fan and the OLTC at the 345㎸ power transformer, were analyzed and corona noise from overhead transmission line in 345㎸ substation were measured to remove the electrical and mechanical noises from the transformer. Furthermore, ultrasonic signal due to the partial discharge in the 154㎸ power transformer with in $C_2$$H_2$ gas warning condition was measured. The inside of the transformer was examined with care. which confirms the existence of the partial discharge source.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.4
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• pp.172-177
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• 2006

During normal machine operation, partial discharge(PD) tests were performed with partial discharge analyzer(PDA) in two hydrogenerators. Six cable couplers were installed in circuit ring bus and endwinding of three phases. PDA showed that the normalized quantity number(NQN) and the partial discharge magnitude$(Q_m)$ were very low in hydrogenerator #1 and #2, respectively. The trend analyses of NQN and $Q_m$ value are available for monitoring of the insulation condition in hydrogenerator stator windings. The insulation condition of stator winding can be assessed. Discharge at conductor surface was discovered in B phase(C2 coupler) of hydrogenerator #1. Internal discharges were generated in A and C phases(C2 coupler) of hydrogenerator #1 and in A, Band C phases(C1 and C2 couplers) of hydrogenerator #2. Slot discharges occurred in A, Band C phases(C1 coupler) of hydrogenerator #1. The stator windings of two hydrogenerators were in good condition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.225-228
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• 2001

Partial discharge(PD) testing for different capacitive couplers was performed on a 6.6kV, 448kW pulverizer motor. The motor has been in service for twenty years. PD tests were measured using digital partial discharge detector(DPDD) and partial discharge analyzer(PDA), respectively. PDA is used to in the motor stator insulation, which three 80pF or three 500pF epoxy-mica couplers were installed, one per phase. The 500pF couplers did detect more normalized quantity number(NQN) than the 80pF couplers. DPDD and PDA showed that PD and NQN magnitudes increased with increase of ac voltage. Internal discharge was discovered in the motor stator insulation. DPDD and PDA test results are in accordance with the pattern and magnitude of PD.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.32 no.7
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• pp.227-233
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• 1983

Noticing that action of gaseous phase in insulating oil concerns to the discharging characteristics, I investigated the smalness pressure effects on quantity of the partial discharge and discharging pulse frequency. Tests are carried out between the niddle points in insulating oil at pressure being changed by gradual charge of inert gas Ar. At pressure as low as of 0.1-0.5 torr pulse frequency and maximum partial discharge reach peak while at pressure haigher than 20 torr no pulse is observed. The fact that pulse frequency has peak value at certain presure, which is changed either by charging Ar or by adding oil, implies that the action of gaseous phase depends on pressure. Test results are that partial discharge pulse are governed by pressure of Ar-charged oil, and less partial discharge pulses correspond to smaller bubbles whereas more partial descharge pulses correspond to larger bubbles.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.423-425
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• 2004

This raper deals with a platform for diagnosis monitoring of partial discharge based on Java virtual machine. This platform is designed for estimating diagnostic parameters of partial discharge signal and displaying Web-page on operating status. For Web-service, hardware of platform is based on a Strongarm processor and software base is designed on Linux and java virtual machine.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2001.11a
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• pp.145-149
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• 2001

The most of faults in gas insulation of power facilities are caused by partial discharge. Therefore we simulated partial discharge and measured the radiated electromagnetic wave emitted from partial discharge in SF$_{6}$ gas by biconical antenna. This paper describes time delay and electric fields pulse characteristics of radiated electromagnetic waves with distance(1[m], 3[m], 5[m]) between antenna and discharge source.e.

• Proceedings of the KIEE Conference
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• 1990.07a
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• pp.283-285
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• 1990

This paper describes on partial discharge in polyethyelen that are important for materials analysis, and so to will introduce to system of partial discharge analysis. The results of this study will be provided on properties of partial discharge in polymer materials.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.6
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• pp.1083-1088
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• 2016

25.8kV GIS part generated by sensors to measure contact an inflow of noise depending on the extent of the measured discharge occurs often not easy. Partial discharge signal measurement sensor suitable for developing a more useful measurements at the scene to this, partial discharge waveform analysis developed a sensor, and to utilize forSensor on the development of the most important is VSWR decided to (voltage standing wave ratio) voltage standing-wave ratio less than 1.5 and decided less than at the full spectrum bands that are measured, this time Return loss, as measured value by absolute criteria 14.0 dB produced the sensor, designed to or more. UHF 1.5~0.5 GHz bandwidth spectrum to be measured in GIS. UHF bands were designed to be able to measure the best signal. Recently, 25.8kV GIS production company has been increasing variety of GIS were made open spacer in partial discharge in accordance with the not very easy to detect the signal. The sensor is designed height of four cm external spacer is attachment GIS in an influx of outside noise measurement, and be so manufactured as to facilitate the least we've done. Also, since partial discharge which occur can measure the frequency of the 170kV GIS external partial-discharge signals that occur at the scene of insulation applied to the spacer. Features, and also derived good results using global positioning. Also measured discharge point about sensors that are stable and the reliability of the development and local substation equipment failure occurring signal analysis through the discharge for the prevention of widely. There should be to believe that used.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.2
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• pp.162-168
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• 2006

Recently, diagnosis techniques have been investigated to detect a Partial Discharge associated with a dielectric material defect in a high voltage electrical apparatus, However, the properties of detection technique of Partial Discharge aren't completely understood because the physical process of Partial Discharge. Therefore, this paper analyzes the process on surface discharge of polymer insulator using wavelet transform. Wavelet transform provides a direct quantitative measure of spectral content in the time~frequency domain. As it is important to develop a non-contact method for detecting the kaolin contamination degree, this research analyzes the electromagnetic waves emitted from Partial Discharge using wavelet transform. This result experimentally shows the process of Partial Discharge as a two-dimensional distribution in the time-frequency domain. Feature extraction parameter namely, maximum and average of wavelet coefficients values, wavelet coefficients value at the point of $95\%$ in a histogram and number of maximum wavelet coefficient have used electromagnetic wave signals as input signals in the preprocessing process of neural networks in order to identify kaolin contamination rates. As result, root sum square error was produced by the test with a learning of neural networks obtained 0.00828.