Method for Locating Faults in Ungrounded Power Distribution Systems

A system 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 a processor for:
• comparing, in response to detecting the fault on a faulty phase of a wire in the distribution system, a difference between an angle of a voltage and an 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 art angle of a voltage and an angle of a it 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 based on proportionality of the distance with impedance of the line segment and a proportionality of the distance with a shunt admittance of the line segment to produce the location of the fault.