Modeling and simulation of air-gapped current transformer based on Preisach Theory

Wu, Ya Hui; Dong, Xin; Mirsaeidi, Sohrab

doi:10.1186/s41601-017-0046-0

Cited by 14 publications

(6 citation statements)

References 15 publications

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“…The faulted section can then be isolated, and other parts of the microgrid can be resupplied with power. A low-bandwidth communication system is required to achieve this, which can be realized through coordination with a traditional distribution protection system [26] - [28]. The detected sign of the adjacent CT is sent to the local CT and compared according to (13).…”

Section: Proposed Protection Methodsmentioning

confidence: 99%

A Protection Method for Inverter-based Microgrid Using Current-only Polarity Comparison

Wang

Jing

2020

Journal of Modern Power Systems and Clean Energy

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The design of an effective protection system for inverter-based microgrids is a complicated engineering challenge. This is due to the fact that inverters have limited fault current capabilities, and that the conventional overcurrent protection is not suitable for inverter-based microgrids. This paper introduces a novel protection method for inverter-based microgrid using a current-only polarity comparison. The proposed method is based on the phase difference between the pre-fault and fault current components. The method responds to faults in both grid-connected and autonomous operation modes and provides a new way to identify faulted sections. Simulations of an inverter-based microgrid with a relay model are conducted using PSCAD/EMTDC software. The results show that the proposed method can detect faults in inverter-based microgrids.

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Section: Proposed Protection Methodsmentioning

confidence: 99%

A Protection Method for Inverter-based Microgrid Using Current-only Polarity Comparison

Wang

Jing

2020

Journal of Modern Power Systems and Clean Energy

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“…refers to the excitation inductance, and and are the total resistance and inductance of the secondary, respectively [10]. From Fig.…”

Section: A Current Transformer Basicsmentioning

confidence: 99%

“…This will produce errors and malfunction of protection or measuring equipment. Hence, in order to solve the issue, manufacturers inserted a small air gap in the core of the CT [10], as can be seen in Fig. 3.…”

Section: B Air-gapped Current Transformermentioning

confidence: 99%

“…(9) After that, the hysteresis differential equation for reversible susceptibility can be established: (10) Finally, combining (4) to (10), the resultant hysteresis differential equation for magnetization can be obtained by adding together the results of the irreversible and the reversible magnetization: (11) (12) However, (12) contains derivatives with respect to , meaning that it has to be reformulated so that the derivatives are with respect to time. To accomplish this, both sides of ( 12) are multiplied by [13].…”

Section: A Jiles-atherton Modelmentioning

confidence: 99%

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Air-Gapped Current Transformer simulation and accuracy assessment

Oliver

Wang

Zeze

2022

2022 IEEE 21st Mediterranean Electrotechnical Conference (MELECON)

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The implementation of smart grids makes it necessary to have reliable and efficient measuring devices. Current sensors used for metering purposes in the grid must be accurate enough to overcome new challenges that power networks face such as injection of undesirable Direct Current (DC) in the system. A Current Transformer (CT) is a transformer widely used to measure current in an electrical circuit. This paper describes the modelling and simulation of a CT with a variable air gap, provides different results of cases with different air gap ratios and evaluates the respective primary and secondary currents in each case according to the standard IEC for instrument transformers. Results show that if an air gap is present, the transformer only reached an accuracy class of 0.5 when the air gap ratio is 0.001.

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“…Electronic transformers are widely used in electrical power systems, especially the electronic current transformer based on Rogowski coil and the electronic voltage transformer based on capacitive voltage divider [1][2][3][4][5][6][7][8][9]. Since the output signals of Rogowski coil and capacitive voltage divider are proportional to the rate of change of the primary signals, they are required to recover the measured primary signals, which is usually realized by electronic integrator circuits [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

An improved distance relay based on electronic transformer by using instantaneous value after equal transfer processes

Wen

Shi³

et al. 2022

IET Generation Trans & Dist

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This paper analyses the formation mechanism of the transmission distortion of electronic voltage transformer, and points out that the integrator will magnify the transient transfer error and superimpose the dynamic additional component on the output signal, which may cause the transfer distortion of voltage signal in serious cases. To restrict the electronic transformer transient variable error effect on distance relay, a distance relay method using instantaneous value after equal transfer processes is proposed. It directly uses output differential signals of the capacitor voltage divider and Rogowski coil. The capacitor voltage divider and Rogowski coil are decomposed into several typical variable link in series. The virtual digital transfer link, which is constructed by the digital filter, is used to compensate for the difference parts of the transfer link, so that the voltage and current signals pass through the same transfer link. It can mitigate the influence of voltage and current signal transfer difference on the calculation accuracy of distance relay. The simulation results show that the proposed distance relay method has fast operation speed and is less affected by abnormal voltage and current signal transfer, and its performance is better than existing distance relay methods.

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Modeling and simulation of air-gapped current transformer based on Preisach Theory

Cited by 14 publications

References 15 publications

A Protection Method for Inverter-based Microgrid Using Current-only Polarity Comparison

A Protection Method for Inverter-based Microgrid Using Current-only Polarity Comparison

Air-Gapped Current Transformer simulation and accuracy assessment

An improved distance relay based on electronic transformer by using instantaneous value after equal transfer processes

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