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This paper evaluates an electronic current transformer’s wideband accuracy in the transformation of distorted current harmonics. The tests were performed in the range of frequencies from 50 Hz to 5 kHz. The utmost importance was dedicated to the transformation of the low-order higher harmonics. The novelty of this paper involves the analysis of the self-generation of the third and fifth higher harmonics caused by the nonlinearity of magnetic core magnetization characteristics. Therefore, what is considered new in this investigation is that this phenomenon has a significant influence on values of current errors and phase displacements despite the presence of the operational amplifiers and the Hall sensors in the output circuits. Another important factor to consider is the influence of the RMS value of the primary current and output load of the ECT on wideband accuracy. To show the backgrounds of the performed laboratory studies, we also discuss the operation principles of the ECTs with closed and open feedback loops. The accuracy of the tested ECT deteriorated—as with the inductive CT—by the self-generation phenomenon. This resulted in rapid changes in the values of current errors and phase displacements determined for the low-order higher harmonics.

DC electronic current transformer is the data source of the system control and protection device, so its measurement delay has always been concerned. In this paper, the DC current transformer is modelled equivalently and the key factors affecting the delay of shunt and the remote module are analyzed. A field test method for the delay characteristics of the DC electronic current transformer is proposed. Moreover, a complex multi-state large current generator and integrated test system are developed. On the basis of the IEC 60044-8 standard transmission protocol, the accuracy of standard signal acquisition with the shunt is better than 0.2%. The maximum output current of the established testing system is 600 A. Based on the field test in an actual HVDC project, transient step and various frequency signal components are applied for analyzing.

Transformer failures are currently a major issue due to the widespread use of electronic transformers in smart grid monitoring systems. To stimulate regular upkeep practices, and raise grid reliability and efficiency, this work developed a sophisticated fault diagnosis approach for electronic current transformers (ECTs) utilizing analytics from big data. For efficient defect diagnosis in the ECT, the dynamic eagle perching optimized long-short term memory (DEPO-LSTM) technique is proposed. Fault sample datasets for ECTs are collected from big data to train the proposed approach. Min-max normalization is used in data preprocessing to remove noisy or redundant information. From the normalized data, important features are extracted using principal component analysis (PCA). Next, we apply the proposed technique in the framework for fault diagnosis, and the DEPO technique is used to improve the parameters of the LSTM. The simulations are carried out using the Matlab platform to assess the proposed DEPO-LSTM technique for ECT defect diagnostics. Based on the results, we deduced that our proposed approach outperformed other approaches presently in use for diagnosing ECT faults. The DEPO-LSTM algorithm is evaluated in terms of precision (97.15%), recall (97.42%), accuracy (96.23%), and F1-score (96.36%).

The electronic current transformer (ECT) acquisition card is widely used in smart grids with many advantages. However, with the continuous improvement of the power grid and localized intelligent electronic devices, the electromagnetic environment under the operating conditions of gas insulated switchgear (GIS) substations is becoming more complicated. The reliability and safety of the ECT acquisition card will be endangered due to the complicated electromagnetic environment. In order to solve these problems, this paper investigates the electromagnetic disturbed mechanism of the ECT acquisition card. The effects of different grounding methods on the electromagnetic interference of the ECT acquisition card were studied. A platform based on IEC 61000-4-4 was built, and the electromagnetic interference (EMI) of the ECT acquisition card with different grounding methods was measured. The results show that the lower grounding impedance of the ECT acquisition system increased the internal EMI. Further, the high frequency electrical fast transient/burst coupling mechanism was analyzed. The parasitic parameters of the acquisition card were extracted based on the critical circuit by using the finite element method. Then, the high-frequency EMI coupling model of the ECT acquisition card was established.

In this paper, we study the conducted interference to an electronic current transformer introduced in the process of bus-charging currents which are caused by switching a gas insulated switchgear (GIS) disconnector. To cope with these issues, the EMTP-ATP and Matlab/Simulink software are used to carry out equivalent modeling simulations and experimental research, respectively. More specifically, the very fast transient current generated by disconnector switching (DS) is used as the input source of the equivalent simulation model of the Rogowski coil, and the characteristics of conducted interference waveforms of the Rogowski coil, the active integrator and filter outputs under single and multiple breakdowns are analyzed step by step. Moreover, several anti-interference methods are proposed to improve the resistance to the high-voltage and high-frequency conducted interference for the Rogowski coil, such as reducing the Rogowski cut-off frequency, increasing the transient voltage suppressor (TVS), active filter, and Cy capacitor. Besides, the study also reveals that the residual charge of the integral capacitor will discharge with a time constant τ = 1 s after arc quenching with the first-order discharge circuit, which is composed of the feedback resistance and the integral capacitor C. Lastly, the experimental results demonstrate the correctness of the modeling method proposed in this paper and the effectiveness of anti-interference measures.

We describe the effect of noise generated by electric circuits in a measuring digital electronic current transformer on measurement accuracy. It is shown that the systematic error is affected by the parameters of the analog anti-aliasing filter, while the random error component is affected by the parameters of the digital averaging filter.

With the extensive use of electronic current transformer, check the original method cannot meet the requirements of electronic current transformer performance testing technology. In 500 kV Jincheng a variable electronic current transformer as the test object, the principle and design characteristics of electronic current transformer, proposes an effective test method, ratio and through field test of low power coils and Rogowski coils 2 coil error, phase error and polarity, verify the validity and accuracy of the method.

This paper mainly analyses, improvement and experiment using the device of Wuhan Hua gong Electric Automation Co., Ltd. existing. As a comparison, this paper firstly analyzes the measuring principle of electromagnetic current transformer and the saturation problem, coil measurement principle and error, a brief summary of the distinction between the two. One time, two times of converter and the merging unit as part of electronic current transformer, this paper also made some analysis. Then analyzed some improvement of transformer differential protection of electronic current transformer based on improved. Firstly, the hardware protection data interface part of, through the analysis of the reasonable selection, then it is based on transformer differential protection of electronic current transformer, the two line ratio braking curve formulation through the analysis of unbalanced current sources, make do with electromagnetic current transformer current unbalance and the ratio braking curve based on the comparative analysis. Finally, the relay protection software the program is changed the basic function of the device is tested, the test results showed that the improved protection device.

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.

A relatively newer generation of magnetic field sensors has found application in broadband electric current measurement. They are based on the magnetoresistance (MR) effect, remain linear for strong magnetic field stimulus, and can operate at a wide band of frequencies. This chapter explains the study of the effect of sensor size, and then designs a measurement system with small MR sensor head. A single magnetic sensor can be employed for large current measurement when placed in the close vicinity of a conductor. However, the magnetic field is complex in modern substations. Higher sensitivity limits the application of MR sensors in environments with nearby magnetic noise sources. A novel method for a wide range of electric current measurement with tunnel magnetoresistance sensors has been proposed to reduce the effect from an adjacent current‐carrying conductor, which is verified by numerical simulations, finite element analysis of the field, and laboratory experiments in the presence of strong magnetic disturbance.