scholarly journals The Method to Determine the Turns Ratio Correction of the Inductive Current Transformer

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8602
Author(s):  
Ernest Stano
Keyword(s):  
Correction Factor ◽  
Current Transformer ◽  
Frequency Characteristics ◽  
Magnetization Curves ◽  
Current Transformers ◽  
Current Error ◽  
Ratio Correction ◽  
Secondary Winding ◽  
Load Conditions ◽  
Load State

This paper presents the method for evaluation of the turns ratio correction of the inductive current transformer using the magnetization curves determined at the non-load state and in the load conditions. The presented method may be applied to determine even a fractional winding correction factor. The standard IEC 61869-2 provides the method to determine the turns ratio correction of the tested CT from the measured rms values of voltages on its primary and secondary winding in the non-load state. However, this approach is limited in determining the significant changes in the number of turns of the secondary winding. Moreover, the paper presents the influence of the applied turns ratio correction on the frequency characteristics of the current error and phase displacement of the inductive current transformers evaluated for the transformation of the distorted current.

scholarly journals Influence of the Selection of the Core Shape and Winding Arrangement on the Accuracy of Current Transformers with Through-Going Primary Cable

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1932
Author(s):  
Elzbieta Lesniewska
Keyword(s):  
Current Transformer ◽  
Analytical Models ◽  
Current Transformers ◽  
Accuracy Class ◽  
Real Model ◽  
Current Error ◽  
Location Change ◽  
Measurement Location ◽  
Physical Phenomena ◽  
Metrological Requirements

The current transformers with split-core are used for installation in places where it is impossible to install classic current transformers. Moreover, this design allows for any measurement location change, and even switching one current transformer into several different shapes of bars or cables. Power network operators, striving for more accurate current measurements, require producers to provide current transformers with a special accuracy class 0.2S. Therefore, manufacturers and designers try to meet the market requirements and, similarly to non-demountable current transformers, i.e., with a toroidal core, design current transformers with split-core class 0.2S. To meet the high metrological requirements, 3D analyses of electromagnetic fields were performed, taking into account physical phenomena and not approximate analytical models. Two types of cores and four different arrangements of the secondary windings of the measuring current transformers were considered. The magnetic field distributions, current error, and phase displacement diagrams of all current transformer models were analyzed, and the model of the transformer structure with the best accuracy was selected. Computations were conducted based on the finite element numerical method, and the results were compared with the real model tests.

scholarly journals Range Automatic Adjusted Current Transformer Primary Winning

2021 ◽  
Vol 12 (3) ◽  
pp. 3142-3147
Author(s):  
Amirov Sultan Fayzullayevich Et.al
Keyword(s):  
Correction Factor ◽  
Driving Forces ◽  
Operating Mode ◽  
Current Transformer ◽  
Measuring Range ◽  
Secondary Current ◽  
Measuring Devices ◽  
The Difference ◽  
Protection And Control ◽  
And Control

The article discusses the issue of introducing a correction factor for protection and control devices, as the value of the secondary current in a certain range of the auto-adjustable current transformer does not correspond to the value of the secondary current in another range determined by the difference of magnetic driving forces generated by the components of the primary current. Alternatively, an algorithm has been developed to account for the measurement error in this condition in an automatic system that controls the operating mode of the current transformer. It was also found that the output data should be transmitted taking into account the correction factor in order to ensure the proper operation of the protection and measuring devices when the current transformer is switched to another measuring range in the measuring range.

Design and Analysis of PCB Rogowski Coil Current Transformer

2014 ◽  
Vol 672-674 ◽  
pp. 984-988
Author(s):  
Biao Su ◽  
Li Xue Li ◽  
Yi Hui Zheng ◽  
Xin Wang ◽  
Yan Liu ◽  
...  
Keyword(s):  
Power System ◽  
High Sensitivity ◽  
Current Transformer ◽  
Rogowski Coil ◽  
Electromagnetic Current ◽  
Current Transformers ◽  
Coil Current ◽  
Electronic Current ◽  
Rogowski Coils ◽  
Electronic Current Transformers

Electronic current transformers are more suitable for the development of power system compared with traditional electromagnetic current transformers. Rogowski coil current transformer is one of three electric current transformers. According to the measurement principle of Rogowski coils, the equivalent circuit of PCB Rogowski coils is analyzed. By using four PCB Rogowski coils combined, a PCB Rogowski coil current transformer is designed and tested. The results show that the designed PCB Rogowski coil transformer has good linearity and high sensitivity and measurement accuracy and it can meet the requirement of power system.

Simulation Model for Assessing Operational Performance of Current Transformers

2007 ◽  
Vol 18-19 ◽  
pp. 71-77
Author(s):  
I. Sule
Keyword(s):  
Simulation Model ◽  
Current Transformer ◽  
Operational Performance ◽  
Current Transformers ◽  
Correct Operation ◽  
Operational Conditions ◽  
Secondary Current ◽  
Protection Scheme ◽  
The Core ◽  
Instrument Transformers

In determining the correct operation of relays of a protection scheme, proper representation of instrument transformers and their behavior in conditions where there can be saturation, is very critical. The main objective of this paper is to develop simulation model for assessing the operational performance of Current Transformer (CT). In order to test the validity of the developed model, three cases of CT operational conditions were considered, with data collected from Gombe, 330/132/33kV PHCN substation. The simulation results revealed various configuration performance responses that could affect relay protective schemes to different degrees. The CT responses revealed that the secondary current and voltage were distorted when the core flux linkages exceeded the set 9.2 pu saturation limit. It is concluded that the model developed for the CT of interest yield satisfactory results.

High-frequency displacement current transformer with just one winding

2019 ◽  
Vol 38 (4) ◽  
pp. 1141-1153 ◽  
Author(s):  
Yahia Achour ◽  
Jacek Starzyński
Keyword(s):  
High Frequency ◽  
Design Methodology ◽  
Current Transformer ◽  
Magnetic Core ◽  
Displacement Current ◽  
Frequency Range ◽  
Content Type ◽  
The Core ◽  
Difference Time ◽  
Secondary Winding

Purpose This paper aims to describe a new concept of transformer based on the displacement current. The paper shows how this idea can be translated into reality and presents an example of a working design. Design/methodology/approach The authors replace the primary winding of the transformer with a capacitor. The displacement current between the capacitor plates induces a magnetic flux in the core. This flux in turn induces electromotive force in the classical secondary winding. Findings The basic mathematical aspects illustrated by results obtained from a simulation developed using a commercial software ANSYS-HFSS are given. The saturation of the magnetic core due to the applied high-frequency range is investigated and simulated using a finite difference time domain code implemented in MATLAB. A prototype transformer was built and tested; the obtained results confirm the previous ones from simulations. Originality/value A new concept of the single winding transformer was used as a pulse forming circuit.

Error Calculating and Compensating Method of All-Optical Fiber Current Transformer in ± 10 kV DC Distribution Network

2019 ◽  
Vol 14 (11) ◽  
pp. 1606-1615
Author(s):  
Jicheng Yu ◽  
Changxi Yue ◽  
Jun Li ◽  
Dengyun Li ◽  
He Li
Keyword(s):  
Optical Fiber ◽  
Distribution Network ◽  
Current Transformer ◽  
Electromagnetic Current ◽  
Current Transformers ◽  
Wave Plate ◽  
Remote Transmission ◽  
Dc Distribution ◽  
All Optical ◽  
Database Technology

Current transformer is one of the main equipment in ±10 kV DC distribution network. Traditional electromagnetic current transformer has poor anti-jamming capacity and poor insulation, so it cannot realize transient protection. The emergence of all-optical fiber current transformer brings solutions to these problems, which has attracted more and more attention. In this study, aiming at the problem of error and compensation of λ/4 waveform of all-fiber current transformer, the fabrication method of λ/4 waveform is studied, the mathematical model of the waveform is established, the influence of the waveform error on the scale factor is analyzed, and a calculating device of angle difference and ratio difference to compare the error is designed. The device adopts the principle of traceability of quantities to collect the state data of the wave plate. At the same time, in order to collect data for errors, database technology and network technology are used to realize remote transmission of monitoring data. The error of the λ/4 wave plate is compensated, the bidirectional principle generated by the birefringence in the fiber ring is analyzed, and the data logic description of the transformer sensitive ring is performed. The phase delay and the angle of the shaft are selected as the main factors causing the error. Compensation is performed by means of peak segmentation and variable cancellation. In the experimental process, compared with the error sampling of the traditional transformer, the error calculated by the current amplitude and phase angle parameters obtained by the all-fiber current transformer is more accurate, and the compensation scheme can suppress the size of the birefringence and improve sensing accuracy of fiber optic current transformers. This study provides a powerful reference for the error analysis of all-fiber current transformer λ/4 wave plates, which is beneficial to promote the better application of such current transformers.

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.

DESIGN AND TEST OF A NEW HIGH-CURRENT ELECTRONIC CURRENT TRANSFORMER WITH A ROGOWSKI COIL

2014 ◽  
Vol 21 (1) ◽  
pp. 121-132 ◽  
Author(s):  
Ming Zhang ◽  
Kaicheng Li ◽  
Shunfan He ◽  
Jun Wang
Keyword(s):  
Dynamic Range ◽  
Partial Evaluation ◽  
Current Transformer ◽  
Rogowski Coil ◽  
High Current ◽  
Current Transformers ◽  
Electronic Current Transformer ◽  
Electronic Current ◽  
Electro Magnetic ◽  
Electronic Current Transformers

Abstract This paper describes the design and test of a new high-current electronic current transformer based on a Rogowski coil. For better performances, electronic current transformers are used to replace conventional electro-magnetic inductive current transformers based on ferromagnetic cores and windings to measure high-current on the high voltage distribution grids. The design of a new high-current electronic current transformer is described in this paper. The principal schemes of the prototype and partial evaluation results are presented. Through relative tests it is known that the prototype has a wide dynamic range and frequency band, and it can allow high accuracy measurements.

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