Fault-type identification for electric power delivery systems

摘要

Disclosed herein are systems and methods for identifying a fault type in an electric power delivery system using an angle difference between a total zero-sequence current and a total negative-sequence current and a comparison of phase-to-phase currents against a threshold. The angle difference falls into one of a number of predetermined angle difference sectors. Each sector is associated with a phase-to-ground fault type and a phase-to-phase-to-ground fault type or two phase-to-phase-to-ground fault types. The phase-to-phase current(s) of the indicated phase-to-phase-to-ground fault type(s) associated with the sector are compared with a threshold to determine which of the fault types of the sector is the actual fault type. The threshold may be a multiple of a maximum phase-to-phase current.

主权项

1. A system for identifying a fault type in an electric power delivery system from a calculated total zero-sequence current and a calculated total negative-sequence current, calculated from a first plurality of currents associated with a first location of the electric power delivery system and a second plurality of currents associated with a second location of the electric power delivery system, comprising:
a first intelligent electronic device (IED) configured to obtain the first plurality of currents; the first IED configured to:
calculate an angular difference between the total zero-sequence current and the total negative-sequence current;determine which of a plurality of predetermined angular difference sectors includes the angular difference;compare a phase-to-phase current magnitude and a predetermined threshold; and,identify the fault type based on the determined angular difference sector and the comparison of the phase-to-phase current magnitude and the predetermined threshold;wherein the fault is identified as a second-phase-to-third-phase-to-ground fault when:
a magnitude of a second-phase-to-third-phase current is greater than the predetermined threshold; and,the determined sector is one selected from the group consisting of:
a sector associated with a second-phase-to-third-phase-to-ground fault or a first-phase-to-third-phase-to-ground fault; anda sector associated with a second-phase-to-third-phase-to-ground fault or a first-phase-to-second-phase-to-ground fault.