scholarly journals The Research on Anti-DC current Transformer of Dual Iron Core Structure with Air Gap

2021 ◽  
Vol 2133 (1) ◽  
pp. 012030
Author(s):  
Zhongai Lin ◽  
Xingyi Zhang ◽  
Biao Tang ◽  
Feng Shen
Keyword(s):  
Electrical Measurement ◽  
Current Transformer ◽  
Air Gap ◽  
System Stability ◽  
Iron Core ◽  
Saturation Current ◽  
Angle Error ◽  
Ratio Error ◽  
Dc Bias ◽  
Dc Current

Abstract Current transformer (CT) is wildly used in electrical measurement and relay protection. In order to improve the power system stability in DC bias, the CT performance of anti-DC is necessarily to be enhanced. Based on the Jiles-Atherton theory, the magnetization characteristics of iron core with different air gap was analyzed in this paper. A simulation model was established using the Simulink toolbox, and the ratio error and angle error were investigated in different air gap length. Simulation result shows that the maximum magnetic density of iron core almost stays uncharged with the addition of air gap. Furthermore the slope of magnetization curve decreased, which leads to the increase of iron core saturation current. Current transformer with closed and air gap iron core possesses a stable measurement error in condition of severe DC bias.

Error Analysis for Metering Current Transformer with DC Bias

2013 ◽  
Vol 773 ◽  
pp. 58-61
Author(s):  
Shi Hai Yang ◽  
Ke Qi Zhang ◽  
Zhong Zhuang ◽  
Min Rui Xu ◽  
Min Jian Cao ◽  
...  
Keyword(s):  
Error Analysis ◽  
Power System ◽  
Simulation Model ◽  
Digital Simulation ◽  
Current Transformer ◽  
Angle Error ◽  
Ratio Error ◽  
Dc Bias ◽  
Simulation Results ◽  
Different Levels

DC bias widely exists in power system. In order to analyze its influence on metering current transformer (MCT), a new digital simulation model based on Preisach theory is constructed firstly. Using this digital model, the ratio error and angle error of a running MCT are calculated under different levels of DC bias. Simulation results show that the current DC bias in power system has only little influence on the error of MCT.

Study of an accurate electronic power measurement technique using modified current transformer and potential transformer

2019 ◽  
Vol 41 (13) ◽  
pp. 3666-3678
Author(s):  
Sirshendu Saha ◽  
Saikat Kumar Bera ◽  
Hiranmoy Mandal ◽  
Pradip Kumar Sadhu ◽  
Satish Chandra Bera
Keyword(s):  
Phase Angle ◽  
Measurement Errors ◽  
Light Emitting Diode ◽  
Current Transformer ◽  
Power Measurement ◽  
Measurement Unit ◽  
Measurement Circuit ◽  
Angle Error ◽  
Ratio Error ◽  
High Tension

In high tension power measurement, potential transformer (PT) and current transformer (CT) are used in order to reduce high tension voltage and current, respectively. But both PT and CT suffer from ratio error and phase angle error, which may produce severe error in power measurement. In the present paper, modified designs of PT and CT are combined to develop an electronic power measurement circuit in order to reduce the measurement errors. The modified PT and CT have reduced phase angle error and ratio error. In the power measurement circuit, the instantaneous product of the outputs of these PT and CT is determined by using a simple light emitting diode (LED)-light dependent register (LDR) or LED-LDR-based product circuit. The operation of the proto type power measurement unit designed in the present work has been experimentally tested and the measured outputs are compared with the readings of laboratory standard wattmeter. The experimental results are reported in the paper. Very good linear characteristics are observed.

Simulation and Analysis for Current Transformers with DC Bias and Remnant Flux

2013 ◽  
Vol 765-767 ◽  
pp. 2430-2434
Author(s):  
Xiao Qian Tian ◽  
Bao Shu Li ◽  
Lu Shen
Keyword(s):  
Error Compensation ◽  
Current Transformer ◽  
Scientific Basis ◽  
Current Transformers ◽  
Ratio Error ◽  
Full Wave ◽  
Accuracy Of Measurement ◽  
Dc Bias ◽  
Power Metering ◽  
Fourier Algorithm

The transfer characteristics of current transformers (CT) change due to DC bias, which directly impacts the accuracy of measurement and power metering. Based on equivalent circuit models and core magnetizing characteristic, qualitatively analysis current transformer saturation increase errors of CT. Transfer errors under DC bias and remnant flux are also obtained based on J-A model of CT in PSCAD/EMTDC and full-wave Fourier algorithm to show that the ratio error and phase displacement increase with the DC bias. Based on FFT spectrum analysis to identify remnant flux and DC bias provides scientific basis for error compensation of CT.

Influence of DC Bias and Remnant Flux on Measuring Current Transformers

2013 ◽  
Vol 765-767 ◽  
pp. 2268-2271
Author(s):  
Lu Shen ◽  
Shu Tao Zhao ◽  
Pei Zhang ◽  
Bin Hu ◽  
Xiao Qian Tian
Keyword(s):  
Power Systems ◽  
Electric Energy ◽  
Current Transformer ◽  
Simulation Software ◽  
Ratio Error ◽  
Phase Displacement ◽  
Limit Value ◽  
Exciting Current ◽  
Energy Metering ◽  
Dc Bias

Current transformer (CT) is an important transmission equipment in power systems. DC bias and remnant flux can change the working point of CT in the core magnetization curve and has a direct impact on the accuracy of electric energy metering and measurement. The simulation circuit model is built by using the simulation software PSCAD and the change of ratio error, phase displacement and exciting current with DC bias and remnant flux are analyzed. The results show that DC bias and remnant flux will both increase the ratio error and phase displacement in opposite directions and the error size will be far more than the limit value when DC bias and remnant flux exist in same direction at the same time. Furthermore, the existence of DC bias and remnant flux will also cause the raise of exciting current size, asymmetry of exciting current waveform and appearance of even harmonics. This will seriously affect the transmission accuracy of measuring CT.

HTS dc bias coil for 35kV/90MVA saturated iron-core fault current limiter

2008 ◽  
Vol 468 (15-20) ◽  
pp. 2050-2053 ◽  
Author(s):  
W.Z. Gong ◽  
J.Y. Zhang ◽  
Z.J. Cao ◽  
H. Hong ◽  
B. Tian ◽  
...  
Keyword(s):  
Iron Core ◽  
Fault Current ◽  
Fault Current Limiter ◽  
Dc Bias ◽  
Current Limiter

scholarly journals Reach and Operating Time Correction of Digital Distance Relay

2017 ◽  
Vol 7 (1) ◽  
pp. 58
Author(s):  
A N Sarwade ◽  
P K Katti ◽  
J G Ghodekar
Keyword(s):  
Low Voltage ◽  
Electrical Power ◽  
Operating Time ◽  
Current Transformer ◽  
Iron Core ◽  
Electrical Power System ◽  
Voltage Transformer ◽  
Distance Relay ◽  
Correct Operation ◽  
Secondary Current

Current and voltage signals recieved from conventional iron core Current Transformer (CT) and Voltage Transformer plays very important role for correct operation of Distance Distance Relay (DDR). Increase in secondary burden connected to CT causes it to saturate at earlier stage. The saturated CT produces distorted secondary current, causing DDR to under reach and to operate by certain time delay. Rogowski Coils (RCs) are attaining increased acceptance and use in electrical power system due to their inherent linearity, greater accuracy and wide operating current range. This paper presents use of RC as an advanced measurement device suitable for DDR. Case study for validation of use of RC is carried out on low voltage system. The simulation results of Distance protection scheme used for protection of part of 220kV AC system shows excellent performance of RC over CT under abnormal conditions.

Effect of Stator Insulation Failure on the Motor Drive System Performance

2021 ◽  
Vol 35 (11) ◽  
pp. 1370-1371
Author(s):  
Hassan Eldeeb ◽  
Haisen Zhao ◽  
Osama Mohammed
Keyword(s):  
Flux Density ◽  
System Performance ◽  
Induction Machines ◽  
Air Gap ◽  
Drive System ◽  
Self Control ◽  
Motor Drive ◽  
Iron Core ◽  
Insulation Failure ◽  
Motor Drive System

This study investigates the influence of the stator’s turn-to-turn failures (TTFs) on the electromagnetic (EM) fields, such as air gap flux density, flux density in the stator, and rotor iron core inside of direct self-control (DSC) driven induction machines (IMs). The purpose of the investigation is to capture the fault signatures in the air gap EM flux for detecting the stator’s fault at its embryonic stage.

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