Patent ID: 9279847
Filing Date: 2016-03-08
CPC Classification: G01R,Y04S

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 is defined by a pair of buses, and the fault is a bolted single-phase-to-ground fault, comprising: detecting the fault on a faulty phase in the distribution system having the fault; comparing, in response to detecting the fault, a difference between an phase angle of a voltage and a phase angle of a current measured at a root of each feeder from the set of feeders to determine a faulty feeder having the fault; comparing a difference between a phase angle of a voltage and a phase angle of a current measured at boundaries of each section of the faulty feeder to determine a faulty section having the fault; testing each line segment of the faulty section for a change of a sign of a voltage on the faulty phase in the faulty section to determine a faulty line segment; and determining a distance from a terminal bus of the faulty line segment to a location along the faulty line segment having a value the voltage on the faulty phase equals zero to produce the location of the fault, wherein steps of the method are performed by a processor.