• KIEE International Transactions on Power Engineering
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• v.4A no.4
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• pp.214-220
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• 2004

Power quality monitoring is the cornerstone for power quality analysis, diagnosis and improvement. The measurement of power quality (PQ) evolves from instantaneous metering to continuous monitoring. Furthermore, recent technologies enable us to construct more flexible, reliable, rapid and economical power quality monitoring system (PQMS). Therefore, this paper presents an improved PQMS with a new distributed monitoring structure. The proposed PQMS consists of a PQ meter, PQ analyzer and GUI. The PQ meter only collects raw data and the PQ analyzer performs power quality analysis. It has several advantages compared to conventional structures in economic efficiency, modularity, speed, etc. PQ monitoring algorithms to catch steady-state trends and to detect PQ events are also adapted to the proposed structure. Using the proposed structure and monitoring algorithm, a prototype PQMS is constructed and real-time testing is performed.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1517-1518
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• 2006

This paper describes the design and fabrication of a partial discharge(PD) analyzer to evaluate insulation performance for low-voltage electrical and electronic devices. The analyzer consists of an adjustable AC power supply, a coupling network, an amplifier, a shielding encloser, a sample-hold (S/H) circuit and a data acquisition (DAQ) board. The analyzer holds the height of PD pulse for $10{\mu}s$ by the S/H circuit, and this makes possible to measure PD pulses having fast rise and short duration by a low speed analog-to-digital (A/D) converter. The data are transmitted to the personal computer through the DAQ board, and the designed analysis program calculate apparent charges, discharge inception and extinction voltages.

• Proceedings of the Optical Society of Korea Conference
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• 1990.02a
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• pp.26-28
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• 1990

Cw arc 램프로 펌핑하는 Alexandrite 레이저의 형광을 optical Spectrum Analyzer를 이용하여 측정하였다. Vibronic 천이에 해당하는 광대역 형광 스펙트럼이 관측되었고, arc 램프 입력에 따른 peak 형광의 세기 및 peak intensity 파장의 입력 power 의존성을 조사하였다. 형광의 세기는 입력 power에 따라 0.16 /kw의 비율로 증가하였고, peak intensity 파장은 입력 power가 5kw 까지는 5 nm/kw 비율로 장파장쪽으로 이동하였다.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1694-1696
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• 2001

Partial discharge(PD) tests are used to evaluate the insulation condition of stator windings in six 6.6kV motors. These tests were conducted using a conventional partial discharge detector (PDD), turbine generator analyzer(TGA) and partial discharge analyzer(PDA). Off-line PD measurements were performed on six 6.6kV motors. PD magnitudes ranged from 740 pC to 5,100 pC at the normal line-to-ground voltage. Six 6.6kV motors have been equipped with eighteen 80pF epoxy-mica couplers(one per phase) on the motor terminal boxs. The PD pulse from sensors were measured with the TGA and PDA instruments on a normally operating motors. The PDD, TGA and PDA test results showed that internal discharge was detected in voids of the groundwall insulation.

• Korean Journal of Optics and Photonics
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• v.11 no.1
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• pp.13-18
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• 2000

The SiOxNy thin films were prepared on Si(lOO) by reactive RF sputtering method. The reactive gas ratio and the power were used as parameters for depositing SiOxNy thin fims. The properties of ${SiO_x}{N_y}$ thin tilms were investigated by XRD, XPS, refractive index and extinction coefficient analyzer (n'||'&'||'k analyzer), and FfIR. It was found by the results of the x-ray diffraction measurement that SiOxNy thin films were grown to an amorphous structure. From the results of the XPS, and the n'||'&'||'k analyzer, it was found that refractive index was intended to increase with the increasement of the relative nitrogen contents of the ${SiO_x}{N_y}$ thin films.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.7
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• pp.491-499
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• 2018

The conventional calibration method for a noise figure analyzer is to use a noise source. This method is accompanied by a significant irregular ripple in the measurement results, because it does not consider the mismatch of the noise source and noise figure analyzer during calibration. A novel calibration method of the noise figure analyzer is proposed that considers the mismatch between the noise power and noise figure analyzer. A novel noise correlation matrix measurement technique using this method is also proposed. The method determines the noise correlation matrix and the gain of the uncorrected noise figure analyzer using uncorrected noise powers. Then, having determined the gain and noise correlation matrix, the effects of noise figure analyzers were corrected in the measurement results of the noise correlation matrix for the device under test (DUT). Through the proposed method, the measured noise parameters of a DUT showed the same degree of irregular ripples as the result of using the relative noise ratio.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.11
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• pp.79-86
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• 2005

This paper describe a method for measuring line impedance as a function of frequency for an energized powerline in normal operation. A small sinusoidal signal of a powerline communication utility frequency $30khz\~1Mhz$ band is continuously injected into the line, and a implemented impedance analyzer calculates the indoor powerline channel impedance from the measured magnitude and phase of resulting voltage and current. The impedance measurement is executed over a range of frequencies to produce a wideband impedance versus frequency characteristic. Implemented impedance analyzer can analysis powerline communication environments measuring line impedance due to load caused in indoor. And measured analysis information through the database can use to evaluate performance of modem and to decide test environment standard.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.661-664
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• 2000

This paper presents a digital instrument for the power quality analysis in three phase power system where current waveform is non-sinusoidal. It is based on C31 DSP and on a special high-speed data acquisition system. Voltage and current waveforms are acquired and processed by using a simple average power algorithm, The paper also goes on to discuss the performance of an instrument prototype both in terms of accuracy and speed of measurement.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.179-180
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• 2006

The real time monitoring of the power systems covering wide area are essential for the stable operation and control of the power system. Synchronized phasor measurement is a key for the precise monitoring and control of the power systems. In this paper, to suggest an appropriate network topology of Power Infrastructure Defense System(PIDS) and to estimate the maximum network bandwidth with using the network analyzer, we simulate a PIDS and analyze the network traffic.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1041-1042
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• 2011