Method and apparatus for detecting leakage current on a two wire DC or AC power line

• Main Author: HALVORSON; DAVID H
• Format: Patent
• Language: English
• Published: 03.10.2000
• Edition: 7
• Subjects: CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; ELECTRICITY; EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS; GENERATION

A method and apparatus detects leakage current on a two wire power line and, in particular, provides a way to prevent hazardous electrical shocks to personnel on ECP equipped railroad trains. Two resistors of equal value are respectively connected in series to the two wires of the power line. A sensing resistor is connected in series with a junction of first two resistors, and a low voltage power source is connected between the sensing resistor and earth ground. A sensor is connected across the sensing resistor to detect a leakage current. The sensor is capable of detecting either positive or negative leakage currents. An output of the sensor is supplied to a controller which controls a high voltage power source connected across the two wires of the power line to be either in an OFF state or enabled to be in an ON state, depending on whether a leakage current is sensed by the sensor.