The effect of earth fault current harmonics on tripping of residual current devices

Czapp, Stanisław

doi:10.1109/isncc.2008.4627489

Cited by 33 publications

(13 citation statements)

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“…In order to avoid the effect of a high frequency waveform on electromechanical relay, an AC/DC converter in the secondary circuit of the current transformer may be used (Fig. 13) [17].…”

Section: Properties Of a Modified Current Transformer For High Frequementioning

confidence: 99%

“…It leads to the problem of RCDs compatibility with such types of current. This problem is discussed in many papers [2][3][4][5][6][7][8][9][10]. Voltage and current harmonics are mainly produced by power electronics converters [2].…”

Section: Introductionmentioning

confidence: 99%

“…For such earth fault currents, the tripping current of residual current devices can be very high [2]. This negatively influences the effectiveness of protection against electric shock.…”

Section: Introductionmentioning

confidence: 99%

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

Czapp

Dobrzyński

Klucznik

et al. 2017

Archives of Electrical Engineering

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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.

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“…In order to avoid the effect of a high frequency waveform on electromechanical relay, an AC/DC converter in the secondary circuit of the current transformer may be used (Fig. 13) [17].…”

Section: Properties Of a Modified Current Transformer For High Frequementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Czapp

Dobrzyński

Klucznik

et al. 2017

Archives of Electrical Engineering

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“…To detect an insulation fault, especially a line-to-earth fault, which potentially introduces an electric shock hazard or fire hazard, a suitable protective device of a proper sensitivity level should be selected and applied. The type of protective device and its operational algorithm depends on the type of power network (grounded, ungrounded, overhead line, cable line) [4,5], the necessity of detection of an arc fault [6,7], distorted voltages [8], special signals [9], DC currents [10,11], and the necessity of detection of non-sinusoidal alternating earth fault currents. Special attention should be given to the currents comprising very-low-frequency components [12] or high-order harmonics [13][14][15][16][17][18][19], as in circuits with power electronics converters [20].…”

Section: Introductionmentioning

confidence: 99%

Testing Sensitivity of A-Type Residual Current Devices to Earth Fault Currents with Harmonics

Czapp

2020

Sensors

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In many applications, modern current-using equipment utilizes power electronic converters to control the consumed power and to adjust the motor speed. Such equipment is used both in industrial and domestic installations. A characteristic feature of the converters is producing distorted earth fault currents, which contain a wide spectrum of harmonics, including high-order harmonics. Nowadays, protection against electric shock in low-voltage power systems is commonly performed with the use of residual current devices (RCDs). In the presence of harmonics, the RCDs may have a tripping current significantly different from that provided for the nominal sinusoidal waveform. Thus, in some cases, protection against electric shock may not be effective. The aim of this paper is to present the result of a wide-range laboratory test of the sensitivity of A-type RCDs in the presence of harmonics. This test has shown that the behavior of RCDs in the presence of harmonics can be varied, including the cases in which the RCD does not react to the distorted earth fault current, as well as cases in which the sensitivity of the RCD is increased. The properties of the main elements of RCDs, including the current sensor, for high-frequency current components are discussed as well.2 of 20 may prevent a person from fatal electric shock, provided that the RCD's rated residual operating current does not exceed 30 mA, which is assumed as the threshold of ventricular fibrillation [3].

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“…Full-wave Fourier algorithm is selected to finish the What's more, in [4,5], the developed construction of residual current devices (RCDs) contains simple discrete components such as electromechanical relay with a permanent magnet. If the residual current transformed by the current transformer reaches a predetermined level, its magnetic flux is high enough to reduce the magnetic flux of the permanent magnet to the level in which the spring is able to pull out the moving armature of the electromechanical relay to open the main circuit.…”

Section: Introductionmentioning

confidence: 99%

An innovative method to achieve minimum tripping current conformity for type A RCCBs

Yan

Sun

2015

IEICE Electron. Express

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This paper presents an innovative method to decrease the discreteness of minimum tripping current for type A residual current operated circuit breakers (RCCBs). Different but continuous time intervals' detection method is proposed to identify the residual current's type and judge whether its root mean square (RMS) value has exceeded the rated value in one cycle. That is, after the timer is started, 0-3 ms ²135°leakage current is detected, 3-7 ms ²90°is detected, 7-12 ms ²0°is detected, 3-7 ms and 12-16 ms type AC is detected. What's more, the method is fabricated in a mixed-signal 0.5 µm CMOS process, and test results show that the type A RCCB's tripping current variation is decreased to 2.8 mA, which greatly improves the chip's reliability and anti-interference ability.

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The effect of earth fault current harmonics on tripping of residual current devices

Cited by 33 publications

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

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

Testing Sensitivity of A-Type Residual Current Devices to Earth Fault Currents with Harmonics

An innovative method to achieve minimum tripping current conformity for type A RCCBs

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