Influences on safety issues for inverter supplied grid structures

Wieland, Thomas; Aigner, Maria; Schmautzer, Ernst; Pasker, Jürgen; Fickert, Lothar

doi:10.1109/pq.2012.6256211

Cited by 5 publications

(2 citation statements)

References 3 publications

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“…Such frequencies change the tripping threshold of RCDs-for very low frequency (e.g., 1 Hz) some RCDs may not trip at all. The impact of mixed-frequency residual currents on RCDs tripping is examined in papers [17][18][19]. They conclude that high-order harmonics may increase the tripping threshold of RCDs which can be quite dangerous for human life.…”

Section: Introductionmentioning

confidence: 99%

Behavior of Residual Current Devices at Frequencies up to 50 kHz

Czapp

Tariq

2021

Energies

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The use of residual current devices (RCDs) is obligatory in many types of low-voltage circuits. They are devices that ensure protection against electric shock in the case of indirect contact and may ensure additional protection in the case of direct contact. For the latter purpose of protection, only RCDs of a rated residual operating current not exceeding 30 mA are suitable. Unfortunately, modem current-using equipment supplied via electronic converters with a pulse width modulation produces earth fault currents composed of high-frequency components. Frequency of these components may have even several dozen kHz. Such components negatively influence the RCDs’ tripping level and, hence, protection against electric shock may be ineffective. This paper presents the results of the RCDs’ tripping test for frequencies up to 50 kHz. The results of the test have shown that many RCDs offered on the market are not able to trip for such frequencies. Such behavior was also noted for F-type and B-type RCDs which are recommended for the circuits of high-frequency components. Results of the test have been related to the requirements of the standards concerning RCDs operation. The conclusion is that these requirements are not sufficient nowadays and should be modified. Proposals for their modification are presented.

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Section: Introductionmentioning

confidence: 99%

Behavior of Residual Current Devices at Frequencies up to 50 kHz

Czapp

Tariq

2021

Energies

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“…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]. If residual current devices are used (they are even obligatory in some circuits), their sensitivity to the non-sinusoidal earth fault (residual) currents has to be verified.…”

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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Circuits with nonsinusoidal currents

Czapp

2022

Residual Current Devices

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Influences on safety issues for inverter supplied grid structures

Cited by 5 publications

References 3 publications

Behavior of Residual Current Devices at Frequencies up to 50 kHz

Behavior of Residual Current Devices at Frequencies up to 50 kHz

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

Circuits with nonsinusoidal currents

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