• Title/Summary/Keyword: VT Comparator

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Evaluation for Ratio Error of Voltage Transformer Comparator using Standard Resistors (표준저항기를 이용한 전압변성기 비교기의 비오차 평가)

  • Han, Sang-Gil;Kim, Yoon-Hyoung;Jung, Jae-Kap;Han, Sang-Ok
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.57 no.4
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    • pp.412-416
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    • 2008
  • We have developed the calibration technique of the VT comparator using nonreactive standard resistors, which evaluates both accuracy and linearity of the VT comparator by comparing experimental values with theoretical values. The correction values of VT comparator obtained by using both our method and wide ratio error VT are consistent within the expanded uncertainty. Furthermore the specification for ratio error of VT comparator have been revaluated.

Construction of On-Site Calibration Facilities of 66 kV Voltage Transformer Comparator System (66kV급 전압변성기 비교측정 장치의 현장 평가설비 구축)

  • Jung, Jae-Kap;Lee, Sang-Hwa;Kwon, Sung-Won;Kim, Myung-Soo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.7
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    • pp.1268-1274
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    • 2007
  • A recently developed methods for the on-site calibration of the voltage transformer (VT) comparator system have been reviewed in the paper. The method utilizes the several traveling standards consisting of the VT, the non-reactive standard resistors, the wide ratio error VT, and the decade resistors. The VT is used for the absolute evaluation of a standard VT belonging to the industry. The non-reactive standard resistor and wide ratio error VT are used for the linearity check of errors in the voltage comparator of the industry. The decade resistors are used for evaluation of a VT burden of the industry.

Evaluation for Phase displacement of Voltage Transformer Comparator (전압변성기 비교기의 위상각 오차 평가)

  • Han, Sang-Gil;Kim, Yoon-Hyoung;Jung, Jae-Kap;Han, Sang-Ok
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.2030-2031
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    • 2008
  • We have developed the calibration technique of the VT comparator using nonreactive standard resistors and a standard capacitor, which evaluates both accuracy and linearity of the VT comparator by comparing experimental values with theoretical values. The specification for phase displacement of VT comparator have been revaluated.

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Evaluation Technique for Linearity of Ratio Error of Instrument Transformer Comparator Using Voltage Transformer with Wide Range of Error Ratios (넓은 범위의 비오차를 갖는 전압변성기를 이용한 계기용 변성기 비교 측정 장치의 비오차 직선성 평가기술)

  • Jung Jae Kap;Kwon Sung Won;Kim Han Jun;Park Young Tae;Kim Myung Soo
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.54 no.2
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    • pp.66-70
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    • 2005
  • Linearity of ratio error of instrument transformer comparator has been tested using wide ratio error voltage transformer(VT) with the ratio errors in the range of -3 % to 3 %. The technique is the method for evaluation of the linearity for instrument transformer comparator by comparing both the theoretical and experimental values in wide ratio error VT. The developed method has been successfully applied for calibration and correction in instrument transformer comparator belonging to industry.

On-Site Calibration Technology of Burden using Voltage Transformer Comparator (전압변성기 비교기를 이용한 부담의 현장교정 기술)

  • Jung, Jae Kap;Kwon, Sung Won;Park, Young Tae;Kim, Myung Soo
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.54 no.11
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    • pp.503-507
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    • 2005
  • Both ratio error and phase angle error in voltage transformer(VT) depend on values of VT burden used. Thus, precise measurement of burden is very important for the evaluation of VT. A method of evaluation for VT burden has been developed by employing the portable decade resistor, with AC-DC resistance difference less than 10-3. The burden value(value and power factor) can be obtained by conductance and susceptance, obtained by measuring the change of ratio error and phase angle error caused by the resistance change of decade resistor. The burden value and power factor obtained by the method are consistent with those obtained using power analyzer within corresponding uncertainties.

Establishment of National Standard System for 240 kV High Voltage Transformer (240 kV 고전압 변성기 국가표준 시스템 구축)

  • Jung, Jae-Kap;Kwon, Sung-Won;Lee, Sang-Hwa;Kang, Jeon-Hong;Kim, Myung-Soo;Han, Sang-Gil;Kim, Yoon-Hyoung;Han, Sang-Ok
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.57 no.2
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    • pp.164-169
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    • 2008
  • National standard system for calibrating voltage transformer(VT) up to primary voltage of 240 kV have been established in 2005. The system consists of voltage source, regulating unit, VT testing unit, standard VT, VT under test and VT burden. To verify and validate the performance for 240 kV VT calibration system, the comparison with the National Measurement Institute of Australia(NMIA) has been performed using same VTs. The comparison results of the VTs mesured at the Korea Research Institute of Stansdards and Science(KRISS) are consistent with those measured at NMIA within 0.002 % for ratio error and 0.14 min for phase displacement in the primary voltage ranges of Vp = 3300 V - 22000 V with a secondary voltage of Vs = 110 V.

Absolute Evaluation of Capacitor and Inductor Using Voltage Transformer Comparator (전압변성기 비교기를 이용한 커패시터와 인덕터의 절대 평가)

  • Han, Sang-Gil;Kim, Yoon-Hyoung;Jung, Jae-Kap;Kim, Han-Jun;Han, Sang-Ok
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.57 no.3
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    • pp.285-290
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    • 2008
  • We have developed the absolute evaluation technique of capacitor and inductor by measuring the phase displacement as a function of resistance of employed resistors in voltage transformer(VT) comparator. The methods were applied to the capacitor with the range of 100 nF - $5{\mu}F$ and the inductor with the range of $100{\mu}H{\sim}1\;H$. The capacitance values of capacitor obtained using our method are consistent within the expanded uncertainty those obtained using capacitor bridge. The inductance values of inductor obtained using our method are also consistent within the expanded uncertainty those obtained using LCR meter.