Patent ID: 9684026
Date: 2017-06-20
CPC Classifications: B60L,G01R,H02H,Y02T

Claim:
1. An automated method for identifying candidate ground fault locations in a high resistance grounded multi-drive system with a multiphase AC source including a neutral connected to a system ground through a high resistance, the method comprising: (i) using a controller with at least one processor operative to communicate with a plurality of motor drives via a communications network, selecting a first one of a plurality of motor drives as a single selected motor drive for testing; (ia) using the controller, closing a system main circuit breaker to connect the multiphase AC source to the plurality of motor drives or to a shared rectifier; (ii) using the controller, disabling all non-selected ones of the plurality of motor drives; (iii) using the controller, enabling the single selected motor drive; (iv) using the controller, determining whether a ground fault is detected while the single selected motor drive is enabled and all the non-selected motor drives are disabled; (v) using the controller, selectively identifying the single selected motor drive as a candidate location of a ground fault if a ground fault is detected while the single selected motor drive is enabled and all the non-selected motor drives are disabled; and (vi) using the controller, selecting at least one remaining untested motor drive of the plurality of motor drives for testing, and repeating steps (ii)-(v) to selectively identify one or more candidate locations of the ground fault or to eliminate further ones of the plurality of motor drives from consideration as ground fault locations.