Low fault current isolator system

摘要

A low fault current isolation arrangement senses a loss of voltage and automatically isolates and de-energizes a down live primary wire if overcurrent protection devices have not cleared the high impedance fault in an electric power distribution network. Incorporating an operator selectable time delay response, the low fault current isolation arrangement permits overcurrent protection devices to attempt to detect and shut down the affected conductor, and then isolates and shuts down the low current fault if the overcurrent devices are not successful. The isolation arrangement continuously monitors AC voltage as remotely provided by smart meters even after a fault location is de-energized, and serves as a back up, and not as a replacement, for existing overcurrent protection schemes. A host computer operates in conjunction with plural smart meters each coupled to an associated customer distribution transformer in conjunction with the fault isolator to detect and shut down high impedance faults.

主权项

1. A tripping mechanism for rapidly and safely directing a high impedance fault in a high voltage conductor to neutral ground, said tripping mechanism comprising:
a solenoid having an arm movable between a first position and a second position and responsive to a signal representing a high impedance fault; an electrically conductive resilient member disposed adjacent said solenoid and engaged and maintained under tension by the solenoid's moveable arm in said first position; a hollow tubular member having first and second opposed ends and containing the high voltage fuse and moveable between a third position and a fourth position; and an electrically conductive rod having first and second opposed ends, wherein the first end of said rod is in contact with the second end of said tubular member when said tubular member is in said third position; wherein when the arm of said solenoid in response to said solenoid receiving a signal representing a high impedance fault moves from said first position to said second position for releasing tension in said resilient member, whereupon said resilient member engages said grounded rod into electrical contact with the high voltage fuse in said tubular member for moving said tubular member from said third position to said fourth position and for directing the high impedance fault via said resilient member to neutral ground potential.