DC feeder protection system

A direct current feeder protection system for use with a combiner box and an inverter, said direct current feeder protection system comprising:

• a first conductor;
• a second conductor;
• a third conductor;
• a fourth conductor;
• a fifth conductor;
• a sixth conductor;
• a first current sensor structured to sense first current flowing in the first conductor from the combiner box;
• a second current sensor structured to sense second current flowing in the second conductor to the combiner box;
• a first two-pole circuit interrupter structured to interrupt currents flowing in the first and second conductors;
• a third current sensor structured to sense third current flowing in the third conductor to the inverter;
• a fourth current sensor structured to sense fourth current flowing in the fourth conductor from the inverter;
• a second two-pole circuit interrupter structured to interrupt currents flowing in the third and fourth conductors;
• and
• a processor cooperating with said first, second, third and fourth current sensors to input said sensed first, second, third and fourth currents, respectively, and to output a number of commands to said first and second two-pole circuit interrupters, said processor comprising a routine structured to detect a number of:
• a directional current fault of said sensed first, second, third or fourth currents, a differential current fault of said sensed first and third currents or said sensed second and fourth currents, and a residual current fault of said sensed first and second currents or said sensed third and fourth currents, and to responsively output said number of commands,
• wherein the first, fifth and third conductors are electrically connected in series with a first pole of each of said first and second two-pole circuit interrupters, and
• wherein the second, sixth and fourth conductors are electrically connected in series with a second pole of each of said first and second two-pole circuit interrupters.