• Title, Summary, Keyword: Power burden

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Development of Automatic Evaluation Equipment for Burden of Instrument Transformer using Resistor Simulator (저항기를 이용한 계기용 변성기 부담 자동 평가 장치 개발)

  • Lee, Young Seob;Jung, Jae Kap
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.4
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    • pp.589-595
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    • 2014
  • The error of instrument transformers is measured by connecting the external burden with the secondary terminal of the instrument transformers. Because the error of transformer is affected by the apparent power and power factor of the external burden, an accurate measurement of burden is important for transformer evaluation. We have developed the burden evaluation equipment for both potential transformer and current transformer by employing the series resistor in the range of $20m{\Omega}{\sim}5{\Omega}$ and the parallel resistor in the range of $1M{\Omega}{\sim}500{\Omega}$, respectively, together with visual basic program. We could reduce testing time more than 5 times by employing method developed in this study, compared with that developed in past. This method shows more better reliability by analyzing the evaluation results and fitting graphs of burden measurements. The test results of the developed system is compared with those obtained in the power meter analyzer to verify the validity.

Development of an Automatic Evaluation System for the Precision Analysis of Potential Transformer Burden Characteristics (전압변성기용 부담특성 정밀분석용 자동평가시스템의 개발)

  • Kwon, Sung-Won;Kim, Mun-Seog;Jung, Jae Kap;Lee, Sung-Ha;Kim, Yung Soo
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.54 no.10
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    • pp.457-464
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    • 2005
  • Both ratio error and phase angle error in potential transformer(PT) are critically affected by used burden, connected in parallel to the secondary terminal of the PT. Thus precise measurement of burden value is very important for the evaluation of PT An automatic measurement system has been developed for the measurement of burden value and power factor of a burden. The ac voltage, current and power of the burden are measured precisely, and the burden value and power factor were calculated from these measured values. The resistance and inductance values of the tested burden are also calculated. The overall measurement uncertainties are calculated and reported with the burden value and power factor. The best measurement uncertainty for the burden measurement with the developed automatic measurement system was estimated to be 0.5 $\%$.

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.

Analysis on Power Burden of HTSC Elements Comprising SFCL using Magnetic Coupling of Shunt Reactors (션트리액터의 자기결합을 이용한 초전도전류제한기를 구성하는 초전도소자들의 전력부담 분석)

  • Lim, Sung-Hun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.1
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    • pp.42-47
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    • 2010
  • The power burden of high-$T_c$ superconducting (HTSC) elements comprising superconducting fault current limiter (SFCL) using magnetic coupling of shunt reactors was analyzed. The magnetically coupled shunt reactors play a role in distributing the even power burden between HTSC elements comprising the SFCL, which contributes to the effective current limiting and recovery characteristics of the SFCL. It was confirmed through the comparative analysis on the SFCLs with both the magnetically coupled and the magnetically uncoupled shunt reactors that the magnetically coupled shunt reactors could improve the SFCL's performance by equalizing the power burden of HTSC elements.

Analysis on Power Burden of HTSC Module due to Fault Current's Amplitude of a Flux-Lock Type SFCL with Two Triggering Currents (두 트리거 전류를 갖는 자속구속형 초전도한류기의 고장전류 크기에 따른 초전도 모듈의 전력부담 분석)

  • Han, Tae-Hee;Lim, Sung-Hun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.29 no.7
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    • pp.424-428
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    • 2016
  • In this paper, the power burden of High-TC superconducting (HTSC) module comprising the flux-lock type superconducting fault current limiter (SFCL) with two triggering currents during the fault period was analyzed. The short-circuit tests for the simulated power system with the SFCL in the different fault positions, which were expected to affect the amplitude of the fault current, were carried out. Through the comparative analysis on the power burden of the HTSC modules, the proposed flux-lock type SFCL was confirmed to be effective to divide into two power burdens according to the amplitude of the fault currents.

Evaluation Technique of Burden for Current Transformer using Current Transformer Comparator and Precise Shunt Resistor (전류변성기 비교기와 정밀션트저항을 이용한 전류변성기용 부담의 평가기술)

  • Lee, Sang-Hwa;Kang, Jeon-Hong;Kim, Myung-Soo;Jung, Jae-Kap
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.55 no.5
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    • pp.250-256
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    • 2006
  • Both ratio error and phase angle error in current transformer(CT) depend critically on values of CT burden. Thus, precise measurement of CT burden is very important for the evaluation of CT. A method for the measurement of CT burden has been developed by employing the portable shunt precise resistor with negligible AC-DC resistance difference less than $10^{-5}$. The burden value(value and power factor) can be calculated from resistance and reactance obtained by measuring the change of ratio error and phase angle error caused by the change of shunt resistor. The uncertainty for the method is evaluated and found to be abut 2 %.

Analysis on Application Location of SFCL according to Circuit Breaker Burden Index with Weight Factor Estimation (차단기 부담 평가지표의 가중치 산정에 따른 초전도 한류기 적용위치 분석)

  • Park, Han-Min;Lee, Hyeong-Jin;Kim, Jin-Seok;Lim, Sung-Hun;Kim, Jae-Chul
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.7
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    • pp.47-53
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    • 2015
  • As the industrial development in Korea, the power demand is rapidly increased. The power system has been extended and complicated to meet the power demand. However, the fault current increases because the structure of power system reduces the equivalent impedance. One of the solutions to reduce the fault current is Superconducting Fault Current Limiter(SFCL) and the researches of SFCL application have much conducted. In this paper, we used the Circuit Breker Burden Index(CBBI) to select application location of SFCL because the CBBI may consider a fault current of each line. In addition, this paper divided the weight factor used to calculate the CBBI on a case by case basis and analyzed this characteristics through experiment.

Optimal Voltage and Reactive Power Scheduling for Saving Electric Charges using Dynamic Programming with a Heuristic Search Approach

  • Jeong, Ki-Seok;Chung, Jong-Duk
    • Journal of Electrical Engineering and Technology
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    • v.11 no.2
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    • pp.329-337
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    • 2016
  • With the increasing deployment of distributed generators in the distribution system, a very large search space is required when dynamic programming (DP) is applied for the optimized dispatch schedules of voltage and reactive power controllers such as on-load tap changers, distributed generators, and shunt capacitors. This study proposes a new optimal voltage and reactive power scheduling method based on dynamic programming with a heuristic searching space reduction approach to reduce the computational burden. This algorithm is designed to determine optimum dispatch schedules based on power system day-ahead scheduling, with new control objectives that consider the reduction of active power losses and maintain the receiving power factor. In this work, to reduce the computational burden, an advanced voltage sensitivity index (AVSI) is adopted to reduce the number of load-flow calculations by estimating bus voltages. Moreover, the accumulated switching operation number up to the current stage is applied prior to the load-flow calculation module. The computational burden can be greatly reduced by using dynamic programming. Case studies were conducted using the IEEE 30-bus test systems and the simulation results indicate that the proposed method is more effective in terms of saving electric charges and improving the voltage profile than loss minimization.

Electric Power Characteristics of a SFCL based on Turn-ratio of 3-Phase Transformer (3상 변압기의 권수비에 따른 초전도 한류기의 전력특성)

  • Jeong, In-Sung;Choi, Hyo-Sang;Jung, Byung-Ik
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.3
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    • pp.414-417
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    • 2014
  • At present, the demand for electric power increases, the electric power system is complicated. The size of the line-to-ground fault and the line-to-line fault occurred with complication of electric power system continue to increase, therefore several issues are raised. To address these issues effectively, the superconducting fault current limiter (SFCL) has been proposed, this study is ongoing. In this paper, we applied the SFCL in three-phase transformer and comparative analysis of the electric power burden to the SFCL. The superconductor is combined to the third winding of transformers in connection structure. In case of a third line-to-line fault, we did comparative analysis of the electric power burden to the SFCL based on the turn ratio of transformer third winding. In this case, we could confirm as the third turn ratio increased, electric power impressed to the superconducting element increased.

Analysis on operation characteristics and power burdens of the double quench trigger type SFCLs

  • Lim, Seung-Taek;Lim, Sung-Hun;Han, Tae-Hee
    • Progress in Superconductivity and Cryogenics
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    • v.19 no.2
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    • pp.33-37
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    • 2017
  • To protect the power systems from fault current, the rated protective equipment should be installed. However growth of power system scale and concentration of loads caused the large fault current in power transmission system and distribution system. The capacities of installed protective equipment have been exceeded the due to increase of fault current. This increase is not temporary phenomenon but will be steadily as long as the industry develops. The power system operator need a counter-measurement for safety, so superconducting fault current limiter (SFCL) has been received attention as effective solutions to reduce the fault current. For the above reasons various type SFCLs have been studied recently. In this paper, operation characteristics and power burden of trigger type SFCL is studied. The trigger type SFCL has been used for real system research in many countries. Another trigger type SFCL (double quench trigger type SFCL) is also studied. For this paper, short circuit test is performed.