Methods and systems for fault detection on direct current power lines

A fault detection system for detecting a fault condition on a direct current (DC) transmission line, the system comprising:

• a transmitter including a power source to energize a transmission line with high voltage DC power;
• and
• a receiver connected to the transmission line to couple the transmission line to a load, and including a signal generator to superimpose a sinusoidal signal on the high voltage DC power on the transmission line,
• wherein the transmitter includes a termination impedance higher than a characteristic impedance of the transmission line to reflect substantially all the sinusoidal signal thereby establishing a standing wave on the transmission line,
• wherein the transmitter includes a first fault detection circuit coupled to the transmission line through a first blocking capacitor and including first touch detection circuitry to detect an amplitude attenuation of the standing wave of more than a threshold amount and, in response, to disconnect the transmission line from the source and to couple the transmission line to ground through a first discharge resistor, and,
• wherein the receiver includes a second fault detection circuit coupled to the transmission line through a second blocking capacitor and including second touch detection circuitry to detect the amplitude attenuation of the standing wave of more than the threshold amount and, in response, to couple the transmission line to ground through a second discharge resistor.