scholarly journals Shock safety modelling of indirect contact with low-voltage electric devices

2011 ◽  
Vol 60 (3) ◽  
pp. 303-315
Author(s):  
Włodzimierz Korniluk ◽  
Dariusz Sajewicz
Keyword(s):  
Ventricular Fibrillation ◽  
Electric Shock ◽  
Low Voltage ◽  
Indirect Contact ◽  
Probability Of Occurrence ◽  
Electric Device ◽  
Shock Protection

Shock safety modelling of indirect contact with low-voltage electric devices The article presents a shock safety model of an indirect contact with a low-voltage electric device. This model was used for computations and analyses concerning the following: the probabilities of appearance of the particular shock protection unreliability states, electric shock states (ventricular fibrillation), contributions of the unreliability of different shock protection elements to the probability of occurrence of these states, as well as the risk of electric shock (and the shock safety), and contributions of the intensity of occurrence of damages to different shock protection elements to this risk. An example of a possibility to reduce the risk of an electric shock through changing the intensity of occurrence of damages to the selected protection elements was provided.

The potential of electric shock for humane trapping of brushtail possums, Trichosurus vulpecula

1994 ◽  
Vol 21 (1) ◽  
pp. 49 ◽  
Author(s):  
ID Dix ◽  
SE Jolly ◽  
LS Bufton ◽  
AI Gardiner
Keyword(s):  
Ventricular Fibrillation ◽  
Electric Shock ◽  
Energy Levels ◽  
High Energy ◽  
Cardiac Response ◽  
Brushtail Possum ◽  
Electric Device ◽  
In The Wild ◽  
Very High Energy ◽  
Major Pest

The Australian brushtail possum is a major pest in New Zealand, and a device to kill possums in the wild by electric shock has been proposed. This investigation was to determine the best waveform and energy level for an electric device to humanely kill possums. The criterion set was a shock which would cause ventricular fibrillation and result in irreversible unconsciousness within a few minutes. Anaesthetised possums were shocked with sinusoidal alternating currents, direct current bursts and impulse waveforms of varying intensities and durations. An electrocardiogram was used to monitor the cardiac response. Although sinusoidal waveforms of a long duration did disrupt the heartbeat and might result in death, even shocks of very high energy levels did not consistently result in ventricular fibrillation. The use of electricity to trap and kill possums appears unacceptable on humanitarian grounds.

scholarly journals Behavior of Residual Current Devices at Frequencies up to 50 kHz

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1785
Author(s):  
Stanislaw Czapp ◽  
Hanan Tariq
Keyword(s):  
Electric Shock ◽  
High Frequency ◽  
Pulse Width Modulation ◽  
Low Voltage ◽  
Residual Current ◽  
Indirect Contact ◽  
Additional Protection ◽  
Operating Current ◽  
Low Voltage Circuits ◽  
Frequency Components

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.

Shock safety modeling method for low-voltage electric devices

2010 ◽  
Vol 59 (3-4) ◽  
pp. 153-167
Author(s):  
Włodzimierz Korniluk ◽  
Dariusz Sajewicz
Keyword(s):  
Bayesian Network ◽  
Electric Shock ◽  
Low Voltage ◽  
Modeling Method ◽  
Shock Protection

Shock safety modeling method for low-voltage electric devices The article describes a shock safety modeling method for low-voltage electric devices, based on using a Bayesian network. This method allows for taking into account all possible combinations of the reliability and unreliability states for the shock protection elements under concern. The developed method allows for investigating electric shock incidents, analysing and assessing shock risks, as well as for determining criteria of dimensioning shock protection means, also with respect to reliability of the particular shock protection elements. Dependencies for determining and analysing the probability of appearance of reliability states of protection as well as an electric shock risk are presented in the article.

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

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 2044
Author(s):  
Stanislaw Czapp
Keyword(s):  
Power Systems ◽  
Electric Shock ◽  
Low Voltage ◽  
Wide Spectrum ◽  
Residual Current ◽  
Motor Speed ◽  
Earth Fault ◽  
Fault Currents ◽  
Wide Range ◽  
Sinusoidal Waveform

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.

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