Joint fault detection and communication for DC power lines

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

• a power transmitter to energize a transmission line with high voltage DC power;
• a power receiver to couple the transmission line to a load;
• at the power receiver, a signal generation means, including,
• means to generate and propagate a high frequency signal on the transmission line using multiple subbands and orthogonal frequency division multiplexing to encode a bitstream that includes a set of message symbols and a set of redundant symbols, and wherein the set of redundant symbols are transmitted on one or more of the multiple subbands;
• and
• at the power transmitter,
• means to receive the high frequency signal, to extract a set of propagated redundant symbols, and to measure, using the set of propagated redundant symbols, a parameter proportional to a channel frequency response of the transmission line,
• means to output a fault signal based on a change in the parameter that exceeds a threshold value, and
• means to, in response to the fault signal, disconnect the transmission line from the high voltage DC power.

A method of detecting a fault condition on a transmission line, the method comprising:

• energizing a transmission line with high voltage DC power from a power transmitter, wherein the transmission line is coupled to a load at a power receiver;
• generating and propagating a high frequency signal on the transmission line using multiple subbands and orthogonal frequency division multiplexing to encode a bitstream that includes a set of message symbols and a set of redundant symbols, and wherein the set of redundant symbols are transmitted on one or more of the multiple subbands;
• receiving, at the power transmitter, the high frequency signal and extracting a set of propagated redundant symbols;
• measuring, using the set of propagated redundant symbols, a parameter proportional to a channel frequency response of the transmission line, wherein the parameter comprises a measured energy of the set of propagated redundant symbols;
• outputting a fault signal based on a change in the parameter that exceeds a threshold value;
• and
• disconnecting the transmission line from the high voltage DC power in response to the fault signal.