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Time response laboratory analysis for residual current devices

Abstract:

Residual Current Devices are protection elements used in many countries for electric shock prevention. These devices detect any differential current flowing from one live line to earth and the mechanism trips opening the circuit avoiding an accident on people. The residual current is standardized based on human tolerance, usually 30 mA. In order to analyze the effectiveness of this protection for real scenarios, in this paper, an experimental research was performed using an electrical human body model including capacitors and resistances. They were applied to the limbs and multiple resistive loads simulating house appliances. Later, in order to generate a controlled leakage current by short circuits, the model was connected to a variable resistive load. After analyzing multiple signals produced in a laboratory, the results showed that a traditional protection relay can trip in average at 8.81 milliseconds almost three times faster than the specifications in the datasheet. Besides, this elements correctly operate for different signal produced by short circuits.