• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1977-1983
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• 2009

This paper described partial discharge(PD) patterns depending on types of insulation defects in CNCO-W cable(Concentric Neutral Closs-linked Polyethylene Insulated Polyolefin-Water Proof Sheathed Power Cable). The PD measurement system consists of a coupling network, a detection impedance, and a low noise amplifier. A 16 bit, 250 MS/s data acquisition system was used to analyze PD patterns. To simulate insulation defects in a power cable, a needle with the curvature radius of $10{\mu}m$ was inserted into the insulation part. We measured phase ($\Phi$), magnitude (q), and counts (n) of PD pulse for the defects, and classified PD patterns using the PRPD (phase Resolved Partial Discharge) method. From the analysis of acquired PD signals, we could find that a unique PD pattern is formed according to the types of defect.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1378-1383
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• 2004

Rogowski coil is a kind of sensor for high amplitude and very short period current and suitable for the measurement of PD pulse. This paper have simulated the relations between PD signals and Rogowski coil which has its own equivalent circuit and investigated signals of Rogowski coil induced by PD pulse current. and compared with the PD signal obtained from conventional PD measuring system in accordance with IEC60270.

• Proceedings of the KIEE Conference
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• 2004.05b
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• pp.97-100
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• 2004

HFPD(High Frequency Partial Discharge) measurement has been widely performed to diagnosis of cable system in the world although Korea just begin. The efficiency of measurement has been reported and proved by many researchers who are engaged in the diagnosis of high power apparatus. LG Cable has investigated the technology of diagnosis for cable system by means of PD measurement for 10 years. In this paper, PD measurement with portable device was performed to evaluate the quality of the 154kV transmission line and the 22.9kV XLPE cable line. Test results are shown that the HFPD detection technology is very attractive for the diagnosis of power cable system by high detection sensitivity at on-site.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1774-1777
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• 1996

In this paper, applicability of SI-PD(switching impulse - partial discharge) testing method was put on an attempt as a newly proposed diagnostic method for the underground distribution power cable system in Korea. For this purpose, SI-PD testing equipment was designed, and tests were performed using artificial needle-type defects integrated into the 22.9 kV CN/CV cables in drder to prove its reliability. As a result, arc noises, generated from spark gap, were considerably decreased by use of a pneumatic switch immersed into oil, and artificial needle-type defects were well detected with impulse voltage level under $2U_0$. These results imply that it is likely possible to apply SI-PD measurement method as a the nondistructive test for the 22.9 kV CN/CV cable system in Korea.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.1
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• pp.45-50
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• 1999

This paper describes a partial discharge (PD) on-line monitoring system used for large turbine generators. The system consists of a broadband current transducer, a computer-aid PD measurement system. By using a programmable fabricate band pass filter and an adaptive digital filter, the system can suppress the noise and extract PD signal from the intense noise surroundings successfully. Two simulated PD sources, which often exist in the large generators, were simulated and detected. At the end of this paper, some field test results, obtained from a 200MW generating set, were presented and discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05b
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• pp.75-78
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• 2001

Recently, the HFPD measurement testing is widely used in partial discharge measurement of HV machines because HFPD measurement testing receives less influence of external noise and has a merit of good sensitivity. Also HFPD testing is able to offer the judgement standard of degradation level of HV machine and can detect discharge signals in live-line. Therefore it is very useful method compare to previous conventional PD testing method and effective diagnosis method in power transformer that requires live-line diagnosis. But partial discharges have very complex characteristics of discharge pattern so it is required continuous research to development of precise analysis method. In recent, the study of partial discharge is carrying out discover of initial defect of power equipment through condition diagnosis and system development of degradation diagnosis using HFPD(High Frequency Partial Discharge) detection. In this study, simulated transformer is manufactured and HFPD occurred from transformer is measured with broad band antenna in real time, the degradation grade of transformer is analyzed through produced patterns in simulated transformer according to applied voltages.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.319-322
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• 1998

Many researchers make efforts to develop an effective material with anti-degradation property. Specially, the porcelain type insulator is required exchanging to polymer insulator acceding to the environmental consideration In this paper, we have developed the estimation system using the PD testing. The approach of PD has been very successful applied to the various practical insulator.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.9
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• pp.727-731
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• 2012

This paper dealt with the measurement and analysis of electromagnetic waves radiated from a partial discharge (PD) source in insulation oil to apply condition monitoring of oil-immersed transformers. Two types of narrow-band monopole antennas with the resonant frequency of a 500 MHz and a 1 GHz were designed and fabricated. Also, a needle-plane electrode system was manufactured to simulate PDs and the curvature radius of the needle is 10 ${\mu}m$ and the diameter of the plane is 60 mm. Electromagnetic wave was measured by the PD measurement system with the monopole antennas. Detection sensitivity of the fabricated antenna was compared for the same PD magnitude; 620 $mV_{peak}$ for the 500 MHz antenna and 960 $mV_{peak}$ for the 1 GHz antenna to the PD magnitude of 74 pC. Consequently, the 1 GHz monopole antenna is more effective to detect PDs in oil-immersed transformers.

• Journal of the Korean Society for Railway
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• v.12 no.2
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• pp.249-253
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• 2009

This paper dealt with the insulation evaluation by a measurement of partial discharge(PD) on traction motors used in a hybrid vehicle. The PD method has been accepted as an effective and a non-destructive. technique to evaluate insulation performance of low-voltage electric and electronic devices. In this paper, the PD measurement system which was manufactured with a coupling network, a low noise amplifier, and an associated electronics is described. The PD measurement system has the frequency bandwidth of $1[MHz]{\sim}30[MHz]$ at -3 [dB] and the stable sensitivity of 19 [mV/pC] for the traction motor. From the experimental results, discharge inception voltage (DIV) and apparent charge (q) were $1,100[V_{rms}]$ and 105 [pC] for the used motor, and $1,400[V_{rms}]$ and 84 [pC] for the new one. By comparing the DIV and q, we could evaluate the insulation condition for the traction motors.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.481-486
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• 2006

In this paper, a new on-line high-voltage motor monitoring system is proposed. This system monitors the insulation condition of the stator winding by on-line measurements of partial discharge (PD). And this system displays magnitude and phase angle distribution of PD. Sensor, CC (Ceramic Coupler) is used for PD measurement. PD signals are continuously measured and digitized with a A/D converter to build the database of the high-voltage motor's insulation condition. Also, this system can communicate with the central monitoring system via RS-232, 422, and TCP/IP. This helps more efficient operation and maintenance of the high-voltage motor.