Electrical link comprising an electrical protection device - current bias

A method to provide a secure supply of electric power to a user apparatus in a vehicle via an electrical link connecting the user apparatus and a power source supplying a DC voltage to the electrical link, wherein the vehicle includes a conductive structure forming a ground and the electrical link includes:

• an electrical conductor surrounded by an insulating cover;
• an electrical protection device including:
• a conductive sleeve arranged around the insulating cover;
• a current generator connected to a current injection point of the conductive sleeve;
• a circuit breaker in series with the conductor and configured to interrupt current transiting in the conductor;
• and
• a detection module comprising a shunt including a first terminal connected to a current tap-off point of the conductive sleeve and a second terminal connected to ground, a comparator including a first input connected to the first terminal of the shunt via a detection line and a second input connected to a DC voltage generator supplying a reference voltage (Vref), and a microcontroller connected between an output of the comparator and the circuit breaker,
• wherein the method comprises as successive steps:
• injection by the current generator of a direct current (Ig) at the current injection point;
• measurement of a magnitude of a current (Ir) via the shunt tapped off at the current tap-off point;
• comparison, by the comparator, of a voltage (Ur) on the detection line and the reference voltage (Vref), wherein the voltage (Ur) is determined from the current (Ir) and the comparator generates of an output signal indicative of the comparison;
• monitoring by the microcontroller of the output signal of the comparator and determining if the output signal indicates a current leak;
• and
• activation, by the microcontroller, of the circuit breaker to interrupt the current in the conductor in response to the output signal of the comparator being indicative of a current leak.

An electrical link system comprising:

• a conductor configured to connect to a DC voltage power source and to an electrically powered user apparatus;
• an insulating cover surrounding the conductor;
• a conductive sleeve around the insulating cover;
• a current generator generating a direct current (Ig) and connected to a current injection point of the conductive sleeve, wherein the current generator applies a the direct current (Ig) to the conductive sleeve;
• a circuit breaker in series with the conductor and configured to interrupt current through the conductor;
• a shunt resistor having a first terminal connected to a tap-off point of the conductive sleeve and a second terminal connected to a ground, and
• a comparator including a first input connected to the first terminal of the shunt resistor and a second input connected to a reference voltage, wherein the comparator generates an output signal indicative of a difference between the voltage applied to the first terminal and the reference voltage applied to the second terminal;
• a controller receiving the output signal from the comparator and, based on the output signal, determines whether to command the circuit breaker to interrupt the current in the conductor.