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100㎷ 이하의 낮은 전류 범위에 대한 변류기 오차 측정 장비의 평가 기술 개발
김윤형(Yoon Hyoung Kim),송의섭(Eui Sub Song),파이살(Agah Faisal),정재갑(Jae Kap Jung),한상옥(Sang Ok Han) 대한전기학회 2009 대한전기학회 학술대회 논문집 Vol.2009 No.10
The evaluation technique for ratio error and phase displacement of current transformer (CT) comparator by using the precise standard capacitors and resistors is applied to ranges below 100 ㎃. By applying this technique for CT comparator which has 10 ㎃ and 100 ㎃ current ranges, we can evaluate the low range of current. The method is applied to CT comparator under test with the ratio error and phase displacement ranges respectively 0 ~ ± 10 % and 0 ~ ± 200 min. Finally we have compared the ratio error and phase displacement of the CT comparator under test theoretically obtained in this method with the specification
金潤亨(Yoon-Hyoung Kim),鄭在甲(Jae-Kap Jung),韓相吉(Sang-Gil Han),丘庚完(Kyung-Wan Koo),韓相玉(Sang-Ok Han) 대한전기학회 2008 전기학회논문지 P Vol.57 No.2
We have developed an absolute evaluation method to obtain the ratio error and phase displacement of a current transformer (CT) without any precise standard CT by measuring four parameters in a CT equivalent circuit. The excitation admittance in the CT equivalent circuit can be obtained by employing standard resistors with negligible reactive component. The secondary leakage impedance in the CT equivalent circuit can be measured using a universal impedance bridge. The method was applied to CTs under test with the wide current ratios in the range of 5 A / 5 A - 5,000 A / 5 A and 5 A / 1 A - 5,000 A / 1 A. The ratio error and phase displacement of the CT under test obtained in this study are consistent with those measured at the national institute in Canada using the same CT under test within an expanded uncertainty (κ = 2) in the overall current ratios.
金潤亨(Yoon-Hyoung Kim),鄭在甲(Jae-Kap Jung),韓相吉(Sang-Gil Han),金韓俊(Han-Jun Kim),韓相玉(Sang-Ok Han) 대한전기학회 2008 전기학회논문지 P Vol.57 No.3
We have developed two absolute evaluation technology of inductor using current transformer (CT) comparator. One is the method that the reactance of inductor is obtained by analysing the equivalent circuit of CT with inductor connected to series at secondary terminal of CT. The other is the method that the reactance of inductor is obtained by comparing phase displacement of current flowing on inductor by using CT comparator. These technologies have the advantage to apply up to rated current and voltage of inductor. The method was applied to inductors under test in the range of 100 μH ~ 1 H. The inductance of the inductor under test obtained in this study are consistent with those measured by LCR meter using the same inductor within an expanded uncertainty (k = 2) in the overall range of inductance.
金潤亨(Yoon-Hyoung Kim),韓相吉(Sang-Gil Han),鄭在甲(Jae-Kap Jung),韓相玉(Sang-Ok Han) 대한전기학회 2008 전기학회논문지 P Vol.57 No.3
We have developed an evaluation technique for ratio errors of current transformer (CT) comparator by using the precise standard capacitors. By applying this technique for equivalent circuit of CT comparator evaluation system, we can obtain the calculated and measured ratio errors in the CT comparator. Thus we can evaluate ratio errors of CT comparator by comparing the calculated and measured ratio errors. Because this method requires only the standard capacitors, it is simple and easy method to reliability and accuracy maintenance of CT comparator. The method was applied to CT comparator under test with the ratio error ranges of 0 ~ ±10 %. The ratio error of the CT comparator under test theoretically obtained in this method are consistent with that measured for same CT comparator under test by using wide ratio error CT within an estimated expanded uncertainty (k = 2) in the overall ratio error ranges.
철심형 전류변성기의 비오차 및 위상오차 절대 평가 기술의 확장
金潤亨(Yoon-Hyoung Kim),韓相吉(Sang-Gil Han),鄭在甲(Jae-Kap Jung),韓相玉(Sang-Ok Han) 대한전기학회 2008 전기학회논문지 P Vol.57 No.4
We have extended an absolute evaluation method to obtain the ratio error and phase displacement of a current transformer (CT) up to primary current of 40,000 A by measuring four parameters of equivalent circuit in CT. The method was applied to CTs under test with the current ratios in the range of 5,000 A / 5 A - 40,000 A / 5 A. The ratio error and phase displacement of the CTs under test obtained in this study are consistent with those measured at the national institutes in Canada and Germany using the same CTs under test within an expanded uncertainty (k = 2) in the overall current ratios.
전류변성기 두 대와 절대 평가 기술을 이용한 2차 전류 범위 확장
김윤형(Yoon-Hyoung Kim),한상길(Sang-Gil Han),정재갑(Jae-Kap Jung),한상옥(Sang-Ok Han) 대한전기학회 2009 전기학회논문지 P Vol.58 No.1
We have developed a current range extension method to obtain the ratio error and phase displacement of a current transformer (CT) by using absolute evaluation method and two different CTs. The method was applied to CTs under test with the current ratios in the range of 5,000 A/1 A - 20,000 A/1 A. The ratio error and phase displacement of the CT under test obtained in this study are consistent with those measured at the national institute in Germany using the same CT under test within an expanded uncertainty (κ = 2) in the overall current ratios.
김윤형(Yoon-Hyoung Kim),한상길(Sang-Gil Han),정재갑(Jae-Kap Jung),강전홍(Jeon-Hong Kang),이상화(Sang-Hwa Lee),한상옥(Sang-Ok Han) 대한전기학회 2009 전기학회논문지 P Vol.58 No.2
Evaluation system for calibrating Rogowski coil(RC) up to primary current of 40,000 A have been established. The system consists of 40,000 A AC high current source, current transformer(CT) comparator, standard CT, RC under test, voltage to current convertor(VCC), buffer and CT burden. An AC high current is applied to the primary windings of both the standard CT and the RC under test, and then the CT comparator measures the ratio error and the phase displacement by comparing the secondary current of the standard CT with output current of VCC. For testing of RC, we have evaluated two RCs under test of primary current ranges of 0 A ~ 2,000 A and 0 A ~ 40,000 A with the accuracy class of 1 %. The extended uncertainty is 0.02 % ~ 0.23 % for ratio error and 0.29 min ~ 1.93 min for phase displacement in the primary current ranges of 10 ~ 40,000 A.