Patent ID: 9316679
Filing Date: 2016-04-19
CPC Classification: G01R

Claim Text:
1. A method for determining a location of a fault in an ungrounded power distribution system, wherein the power distribution system includes a set of feeders connected to a substation, wherein each feeder includes a set of loads connected by line segments and each line segment includes an upstream bus and a downstream bus, and the fault is a bolted single-phase-to-ground fault, comprising: determining shunt caused residual voltages on the upstream bus and the downstream bus of the line segment within a faulty feeder section of a faulty feeder; determining fault caused residual voltages on the upstream bus and the downstream bus of the line segment; designating the line segment as a faulty line segment when a reference angle of a faulty phase is between a first angle of a difference between an angle of the fault caused residual voltage and an angle of the shunt caused residual voltage on the upstream bus and a second angle of a difference between an angle of the fault caused residual voltage and an angle of the shunt caused residual voltage on the downstream bus; and determining a location of a point on the faulty line segment with a difference between the angle of the fault caused residual voltage and the angle of the shunt caused residual voltage in phase with the reference angle of the faulty phase as the location of the fault, wherein steps of the method are performed by a processor.