Method and apparatus for limiting ground fault current

摘要

A ground fault current-limiting circuit for limiting telecommunication wireline voltage and ground fault current to prescribed safety parameters has a ground fault current sense resistor and associated line voltage control circuit installed in a ground-coupling link to the center tap of the output winding of a bipolar voltage converter's output transformer. The control circuit compares ground fault current of either polarity flowing through the sense resistor to a prescribed value. In response to this current limit being exceeded, the control circuit produces an output signal that causes the power source to reduce its output voltage so that the ground fault current will drop to within acceptable limits.