Three-rail power supply system

An asymmetric resistor network for limiting a fault current in a three-rail power supply, the three-rail power supply including a power supply and a rail system, the rail system having a power supply end and a termination end and comprising a positive rail, negative rail, and a ground rail, the asymmetric resistor network comprising:

• at the termination end of the rail system,
• a first resistor having two terminals and a first resistance value, one terminal of the first resistor coupled to the positive rail and another terminal of the first resistor coupled to the ground rail, and
• a second resistor having two terminals and a second resistance value, one terminal of the second resistor coupled to the negative rail and another terminal of the second resistor coupled to the ground rail;
• and
• at the power supply end of the rail system,
• a third resistor having two terminals and a third resistance value equal to the first resistance value, one terminal of the third resistor coupled to the negative rail and another terminal of the third resistor coupled to the ground rail, and
• a fourth resistor having two terminals and a fourth resistance value equal to the second resistance value, one terminal of the fourth resistor coupled to the positive rail and another terminal of the fourth resistor coupled to the ground rail, and
• wherein the negative rail is coupled to a negative terminal of the power supply, the positive rail is coupled to a positive terminal of the power supply, and the ground rail is coupled to a neutral terminal of the power supply through a fifth resistor having a fifth resistance value and electrically grounded to a ground at the termination end, at the power supply end, and at a plurality of intervals between the power supply end and the termination end,
• wherein, in response to one or more of the positive rail, the negative rail, and the ground rail experiencing a faulty connection, the asymmetric resistor network is configured to limit a fault current through the faulty connection.

A method for limiting a fault current in a three-rail power supply, the three-rail power supply including a power supply and a rail system, the rail system having a power supply end and a termination end and comprising a positive rail, negative rail, and a ground rail, the method comprising:

• at the termination end of the rail system,
• coupling a first terminal of a first resistor to the positive rail and a second terminal of the first resistor to the ground rail, the first resistor having a first resistance value,
• coupling a first terminal of a second resistor to the negative rail and a second terminal of the second resistor to the ground rail, the second resistor having a second resistance value,
• at the power supply end of the rail system,
• coupling a first terminal of a third resistor to the negative rail and a second terminal of the third resistor to the ground rail, the third resistor having a third resistance value equal to the first resistance value, and
• coupling a first terminal of a fourth resistor to the positive rail and a second terminal of the fourth resistor to the ground rail, the fourth resistor having a fourth resistance value equal to the second resistance value,
• wherein the negative rail is coupled to a negative terminal of the power supply, the positive rail is coupled to a positive terminal of the power supply, and the ground rail is coupled to a neutral terminal of the power supply through a fifth resistor having a fifth resistance value and electrically grounded to a ground at the termination end, at the power supply end, and at a plurality of intervals between the power supply end and the termination end, and
• in response to one or more of the positive rail, the negative rail, and the ground rail experiencing a faulty connection, limiting the fault current through the faulty connection.