Current Transformer Accuracy with Asymmetric and High Frequency Fault Currents

1981 ◽  
Vol PER-1 (3) ◽  
pp. 41-42 ◽  
Author(s):  
D. A. Douglass
Keyword(s):  
High Frequency ◽  
Current Transformer ◽  
Fault Currents

scholarly journals Improving sensitivity of residual current transformers to high frequency earth fault currents

2017 ◽  
Vol 66 (3) ◽  
pp. 485-494 ◽  
Author(s):  
Stanislaw Czapp ◽  
Krzysztof Dobrzynski ◽  
Jacek Klucznik ◽  
Zbigniew Lubosny ◽  
Robert Kowalak
Keyword(s):  
High Frequency ◽  
Low Voltage ◽  
Current Transformer ◽  
Residual Current ◽  
Fault Current ◽  
Earth Fault ◽  
Fault Currents ◽  
Proper Operation ◽  
Current Device ◽  
A Current

Abstract For protection against electric shock in low voltage systems residual current devices are commonly used. However, their proper operation can be interfered when high frequency earth fault current occurs. Serious hazard of electrocution exists then. In order to detect such a current, it is necessary to modify parameters of residual current devices, especially the operating point of their current transformer. The authors proposed the modification in the structure of residual current devices. This modification improves sensitivity of residual current devices when high frequency earth fault current occurs. The test of the modified residual current device proved that the authors’ proposition is appropriate.

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.

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