• Title/Summary/Keyword: Electrical signals

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A Study on Partial Discharge Measurement using Optical Fiber Sensors (광섬유 센서를 이용한 부분방전 측정연구)

  • Lee, June-Ho;Lee, Cheol-Kyou
    • Proceedings of the KIEE Conference
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    • 1998.11c
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    • pp.922-924
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    • 1998
  • In this paper, an optical fiber sensor(OF sensor) utilizing the principal of Mach-Zehnder interferometer were proposed to detect the partial discharge signals in insulating oil. At first the AC breakdown signals were detected to check the response of the OF sensor. The detected signals from OF sensor was consistent with that from current probe. After the response checking, simultaneous measurements and continuous recording were made of electrical and the OF sensor signals from partial discharge(PD) produced by IEC(b) electrode system immersed in insulating oil. The continuous recording made it possible to extract basic quantities of PD from the OF sensor signals, such as pulse phase and pulse amplitude distribution. Through the signal analysis, the absolute peaks of the OF sensor PD signal was found to be increased with the amplitude of electrical signals, and these results mean that there is a strong correlation between OF sensor and electrical PD signals. It was demonstrated that the OF sensor in this research had a possibility to detect the PD signals in power apparatus.

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Development of a Digital Down-mixer to Convert 5.1 Channel Audio Signals to Stereo Signals (5.1 채널 오디오 신호를 스테레오 신호로 변환하는 디지털 다운믹서 개발)

  • Jeon, Kwang-Sub;Cheong, Ho-Yong;Lee, Seung-Yo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.12
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    • pp.1764-1770
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    • 2013
  • Use of the 5.1 channel audio signals suitable for the television system is improper for the radio broadcasting system, which uses the stereo audio system. Therefore, it is necessary to develop an audio down-mixer to convert 5.1 multi-channel audio signals to stereo signals for radio broadcasting. In this paper, a development of an audio down-mixer was carried out to convert 5.1 multi-channel audio signals to stereo signals. The down-mixer which was developed can use the audio signals separated from video signals, including sound signals or individual signals provided from 3-channel AES/EBU signals including Left(L), Right(R), Left Surround(Ls), Right Surround(Rs), Center(C) and Low Frequency Effect(Lfe) sounds as mixer inputs.

Development of H/W and S/W for Detecting Electrical Fire Precursor Signal on Electrical Wirings (배선에서 전기화재 전조신호 검출을 위한 H/W 및 S/W 구축)

  • Kim, Sung-Chul;Kim, Doo-Hyun
    • Journal of the Korean Society of Safety
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    • v.24 no.3
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    • pp.13-18
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    • 2009
  • This paper is purposed to develop DAQ H/W, S/W and DB which can be used in developing electrical fire alarm system or in analyzing electrical fire cause, by detecting and monitoring precursor signals which have high possibility leading to electrical fire on electrical distribution wires. In this paper, developed was DAQ H/W adopting the C8051FXXX CPU which can analyze the measurement signals of current and voltage in electrical distribution wires, other CPU was investigated in view of the best digital sampling rate on the basis of previous researches for electrical fire alarm system. Also, the S/W which can interface with DAQ H/W's communication protocol and can be applied for electrical fire causes analysis, are embodied by LabVIEW. The combined DAQ H/W and S/W could analyze efficiently normal as well as abnormal electrical signals such as RMS value, instantaneous value of current and voltage, frequency signals etc, on the electrical wires. Also, DB system was constructed for recording various analysis results for precursor signals including voltage and current signals. The results by simulator and experiment showed that the suggested scheme with DAQ H/W, S/W and DB in this paper has high usability.

Analysis of Electrical and AE Signals by Treeing Breakdown (트리잉 파괴에 따른 전기 및 AE신호의 분석)

  • Lee, Sang-Woo;Kim, Seung-Gyu;Kim, In-Sik;Lee, Kwang-Sik;Lee, Dong-In
    • Proceedings of the KIEE Conference
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    • 1999.07e
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    • pp.2335-2337
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    • 1999
  • In this paper, using AE (Acoustic Emission) sensor the electrical and emitted-sound signals are measured by treeing breakdown in the epoxy resin, and the corresponding frequency spectrum of the AE signals are analyzed. We also examined the relationship between partial discharge magnitude and pulse number of AE signals to diagnose the deterioration of the electrical insulation due to treeing breakdown. From these results, a frequency band of AE signals through treeing breakdown was set to about 230 [kHz], and it appeared that pulse number of AE signal was proportional to partial discharge magnitude.

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Sound quality assessment system for the vehicle audio signals (자동차 전장음 음질평가 시스템)

  • Kim, Se-Ung;Choi, In-Yong;Chon, Sang-Bae;Lee, Min-Gu;Sung, Koeng-Mo
    • Proceedings of the IEEK Conference
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    • 2006.06a
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    • pp.351-352
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    • 2006
  • The objective criterion is necessary to decide the signal for vehicle audio. In this time, the signals have decided by golden ear or some simple parameters. In this paper, we propose the system for sound quality assessment in the vehicle audio signals. The vehicle audio signals were recorded in many vehicles by same condition. From these signals, objective and subjective parameters were extracted and using these signals listening test was done. The function was estimated between three results by simple neural network system. The score of arbitrary signal can be estimated using the function made by three results. In this way, Sound signal quality is assessed objectively.

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Detection of Acoustic signals by PD in Test Transformer (시험용 변압기 내 부분방전의 초음파 검출에 관한 연구)

  • Kwak, Hee-Ro;Kweon, Dong-Jin;Chin, Sang-Bum;Jeon, Sang-Jun;Chung, Young-Ki;Song, Il-Keun
    • Proceedings of the KIEE Conference
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    • 1995.07c
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    • pp.1293-1295
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    • 1995
  • This paper describes the detection of the ultrasonic signals reduced by barrier in test transformer. The ultrasonic signals are generated by partial discharges which cause the insulation failure of transformer. The ultrasonic signals are reduced by barrier. But it was shown that the reduced ultrasonic signals can be measured as the location of the ultrasonic signal detectors is selected properly.

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Distribution Characteristics of AE Signals in Insulation Deterioration and AE Noise in Cast Resin transformer (절연물의 열화에 의한 AE신호와 변압기 외함의 AE노이즈 분포)

  • Lee, Sang-Woo;Kim, In-Sik;Kim, Lee-Kook;Park, Won-Zoo;Lee, Kwang-Sik
    • Proceedings of the KIEE Conference
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    • 2002.07c
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    • pp.1865-1867
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    • 2002
  • In this paper, frequency spectra of AE signals detected from respective the insulation deterioration were analysed to under ac high-voltage application using epoxy resin sample and insulation oil. Also, frequency spectra of AE signals generated from the load currents in the actual operating transformer of 500[kVA] under distribution system of 22.9[kVJ] were also analysed to distinguish the AE signals due to void discharges from the magnetic circuit noises in transformer. As the experimental results, we could distinguish the AE signals whether those signals were caused due to the void discharges or due to the magnetic circuit noises by analyzing the frequency spectrum of AE signals.

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Demodulation and Performance of Multicomponent Undersampled AM, FM and AM-FM Signals (다중 성분의 저표본화된 AM, FM 및 AM-FM 신호들의 복조와 성능)

  • Son, Tae-Ho;Hwang, Ui-Cheon
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.49 no.7
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    • pp.399-406
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    • 2000
  • We propose an nonlinear demodulation algorithm for undersampled multicomponent AM(Amplitude Modulation), FM(Frequency Modulation) and AM-FM signals. First, we derive respectively undersampling frequency of the AM, FM and AM-FM using undersampling scheme, and separate respectively monocomponent signals from multicomponent signals using periodic algebraic separation algorithm. In this case augmented separation matrix is very regular and sparse, it has a special structure. The proposed demodulation algorithm detects respectively message signals of the IA(Instantaneous Amplitude) and IF(Instantaneous Frequency) from descrete monocomponent AM, FM and AM-FM signals with an undersampling frequency to be controllable. Verifying the RMS(Root Mean Squares) errors of the detected signals, we show that the performance is excellent.

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Wireless Synchronous Transfer of Power and Reverse Signals

  • Li, Yang;Li, Yumei;Feng, Shaojie;Yang, Qingxin;Dong, Weihao;Zhao, Jingtai;Xue, Ming
    • Journal of Power Electronics
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    • v.19 no.3
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    • pp.827-834
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    • 2019
  • Wireless power transfer via coupled magnetic resonances has been a hot research topic in recent years. In addition, the number of related devices has also been increasing. However, reverse signals transfer is often required in addition to wireless power transfer. The structure of the circuit for a wireless power transfer system via coupled magnetic resonances is analyzed. The advantages and disadvantages of both parallel compensation and series compensation are listed. Then the compensation characteristics of the inductor, capacitor and resistor were studied and an appropriate compensation method was selected. The reverse signals can be transferred by controlling the compensation of the resistor. In addition, it can be demodulated by extracting the change of the primary current. A 3.3 MHz resonant frequency with a 100 kHz reverse signals transfer system platform was established in the laboratory. Experimental results demonstrate that wireless power and reverse signals can be transferred synchronously.

Ultrasonic Characteristics of Oil Corona by Wide-Band AE Sensor (광대역 AE 센서에 의한 유중코로나의 초음파 특성)

  • Kim, In-Sik;Lee, Sang-Woo;Kim, Seung-Gyu;Gu, Kyung-Chul;Lee, Kwang-Sik;Lee, Dong-In
    • Proceedings of the KIEE Conference
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    • 1999.07e
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    • pp.2338-2340
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    • 1999
  • In this paper measurements of AE (Acoustic Emission) signals caused by corona discharge were performed to analyze the electrical deterioration in oil. We also examined the relationship between discharge magnitude and peak-to-peak value of AE signals to diagnose the deterioration of liquid dielectrics. From these results, Vpp(peak to peak value) of AE signals was proportional to corona discharge magnitude. The main frequency band of AE signals in oil appeared to 130[kHz].

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