• 한국컴퓨터산업교육학회:학술대회논문집
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• 2003.11a
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• pp.55-58
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• 2003

Stability of inside power equipments are required for electron equipment in order to operate those safely. Also, the power circuits for these have been developing, but research of dielectric strength of power supply is insufficient. In this paper, for test insulation condition variation by void it is tested insulation characteristics variation, using $\phi-q-n$ distribution variation in partial discharge test.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2093-2096
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• 1999

This paper describes to access the insulation deterioration condition of the stator windings in three large turbine generators. Nondestructive tests have been carried out on stand-still generators which have been in service for 2 to 30 years. In most cases these tests include ac current increase rate($\Delta$I), delta tan delta( ${\Delta}tan{\delta}$), and maximum partial discharge(Qm). Gen. 2 show that the $tan{\delta}$ is higher than other two generators in the $tan{\delta}$-voltage curve. Partial discharge(PD) patterns were observed internal, corona and treeing discharges in large turbine generators. The PD tests were confirmed the correlation between discharge patterns and the kinds of defects.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2392-2395
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• 1999

This paper describes to access the insulation deterioration condition of the stator windings in six high voltage motors. Nondestructive tests have been carried out on stand-still motors. These tests include ac current increase rate($\Delta$I), delta tan delta(${\Delta}tan{\delta}$), and maximum partial discharge(PD). AC current and $tan{\delta}$ were measured by Schering bridge. The measurement of PD patterns were conducted using digital partial discharge detector. PD patterns were observed treeing and internal discharges in Motor 1 and 2. The stator windings of two motors were found to be in a poor condition and their were recommended to rewind. The stator. windings of four motors were judged to be in serviceable condition.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1887-1891
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• 2008

In this paper, we dealt with a partial discharge (PD) measurement method that has been accepted as an effective and non-destructive technique to estimate insulation performance of low-voltage induction motors. The PD measurement system consists of a coupling network, a low noise amplifier, and associated electronics. A shielded box was used to reduce environmental noise. Frequency characteristic of the coupling network was estimated by a sinusoidal signal input, and the low cut-off frequency of the coupling network was 1 MHz (-3 dB). Also, we carried out a calibration test for the PD measurement system. Sensitivity of the system was of 84 m$V_{max}$/pC between stator winding and enclosure. In application test on a low-voltage three phase induction motor (5 HP), we could detect 88 pC at AC 800 $V_{max}$.

• KIEE International Transactions on Electrophysics and Applications
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• v.11C no.2
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• pp.12-17
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• 2001

In this work, the correlation between the PD Patterns and the electrical tree propagation has been investigated by use of the specimen removed from the insulation of the real 154 kV XLPE underground power cables. As a result, it could be deduced that the PD pattern regarding electrical trees depends on their type which could be classified into three different distinct groups such as branch-bush mixed. Considering the results of our investigation, if the partial discharge magnitude is only considered for the diagnosis of the cable system, it is possible to draw a wrong decision. Therefore, it is possible to propose that the time characteristics of PD pattern should be taken into account for the diagnosis of the cable system in addition to the conventional $\Phi$-q-n characteristics.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.415-421
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• 1999

This paper indicate that phase resolved partial discharge patterns are investigated on PET films containing artificial void of varing dimensions. In this study, we measured phase-resolved PD patterns and statistical parameter from PET specimens with IGT(insulation/airgap/insulation) structure by IEC 270 standard. Measurement system is the conventional PD detector using digital signal processing technique. The relationship of diameter and location of artificial void was discussed through the difference of $\pi$-q-n distribution and statistical analysis.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1909-1911
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• 2000

Recently many research activities on the diagnosis of stator winding insulation of large rotating machines have been reported. Capacitive couplers are widely used as sensors for on-line partial discharge (PD) measurement of high voltage rotating machines. This paper presents laboratory test to compare Stator Slot Coupler (SSC), Resistance Temperature Detector (RTD), 80 [pF] coupler and 500 [pF] coupler for on-line PD measurement of rotating machines.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.9
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• pp.786-791
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• 2009

Transformer failures are mostly due to partial discharges (PDs) caused by the deteriorated insulation. It is, therefore, important to monitor PD occurrence in insulation system and prevent their deterioration. The presented paper deals with a PD detection method by a capacitive probe, which easily apply to cast - resin dry - type transformers. The PD detection system consists of a capacitive probe and a low noise amplifier having the frequency bandwidth of 500 $Hz{\sim}30$ MHz. In the experimental set-up, sensitivity of the system is 7.16 mV/pC.

• KIEE International Transactions on Electrophysics and Applications
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• v.5C no.6
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• pp.223-227
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• 2005

Insulation failure of traction motor stator coil depends on the continuous stress imposed on it and knowing its insulation condition is an issue of significance for proper safety operation. In this paper, application of the NN (Neural Network) as a scheme of the off-line PD (partial discharge) diagnosis method that occurs at the stator coil of a traction motor was studied. For PD data acquisition, three defective models were made; internal void discharge model, slot discharge model and surface discharge model. PD data for recognition were acquired from a PD detector. Statistical distributions and parameters were calculated to perform recognition between model discharge sources. These statistical distribution parameters are applied to classify PD sources by the NN with a good recognition rate on the discharge sources.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.304-307
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• 2004

This paper simulated partial discharge caused by 22.9[kV] power cable using XLPE(Peroxide Crosslinkable Polyethylene) insulation having the outside damage. As one of the insulation diagnostic method a radiated electromagnetic waves were measured by an UHF method using a BiconiLog antenna(EMCO-3142) and a spectrum analyzer used to measure EMI, EMC. From results of this study, It was confirmed that discharge progress were possible to be estimated by the proposed method.