Method for detecting ground faults in a LVDC electric line and an electronic device thereof

An electronic device for detecting faults in a LVDC electric line, the line having first and second conductors, the device comprising:

• sensing means for providing at least a measuring signal (VM1, VM2) indicative of an unbalancing current (IG) between the conductors of said electric line;
• filtering means for filtering the measuring signal (VM1, VM2) and providing a first detection signal (VLOW) indicative of low-frequency components of said unbalancing current and a second detection signal (VHIGH) indicative of high-frequency components of said unbalancing current;
• processing means for processing said first and second detection signals (VLOW, VHIGH), said processing means being programmed to perform operations comprising:
• obtaining a third detection signal (RT) by calculating the ratio between said first and second detection signals (VLOW, VHIGH);
• and
• checking whether a DC current (IF) towards ground is present by comparing said third detection signal (RT) with a first threshold value (TH1).

An electronic device for detecting faults in a LVDC electric line, the line including first and second conductors;

• the device comprising:
• a magnetic core enchained with the first and second conductors of the electric line;
• an excitation circuit having an excitation winding wound around said magnetic core and configured to provide an excitation current along the excitation winding;
• a first sensor configured to send a current through the first conductor and provide a first measuring signal (VM1) in response to the excitation current in the excitation winding;
• a second sensor configured to send a current through the second conductor and provide second measuring signal (VM2) in response to the excitation current in the excitation winding;
• a filter configured to (a) low pass filter the first measuring signal (VM1) to output a first detection signal (VLOW) and (b) high pass filter the output a second measuring signal (VM2) to output a second detection signal (VHIGH);
• a processor programmed to perform operations comprising:
• calculating as third detection signal (RT) a ratio between the first and second detection signals (VLOW, VHIGH);
• and identifying a DC current (IF) towards ground in response the third detection signal (RT) exceeding a first threshold value (TH1).