<abstract xml:lang="en" xmlns="http://www.w3.org/1999/xhtml">The notion of fault quotient refers to single-phase-earth and phase-to-phase faults in one-terminal and two-terminal (double fed), single or parallel power lines at determination of the distance to a fault place using the apparent impedance method. The fault quotient is determined as the ratio of the current through a fault place (fault current) to the current in a faulty phase at single-phase-earth faults and to the difference of currents in faulty phases at phase-to-phase faults. For one-terminal lines at single-phase-earth faults, neglecting capacitive and load currents, this ratio is 1, and for phase-to-phase faults it equals 1/2. For other cases it is a complex quantity, with the absolute value > 1 for single-phase-earth faults. Its significance grows with the fault resistance <italic>Rf</italic>. At <italic>Rf</italic> = 0 this ratio loses its significance for determination of the distance to a fault place. The tangent of the fault quotient angle with a real axis enters into the ultimate expressions for the reactance to fault place and for the fault resistance. The use of such a quotient facilitates reiterative calculations of the distance to a fault place.</abstract>

The notion of fault quotient refers to single-phase-earth and phase-to-phase faults in one-terminal and two-terminal (double fed), single or parallel power lines at determination of the distance to a fault place using the apparent impedance method. The fault quotient is determined as the ratio of the current through a fault place (fault current) to the current in a faulty phase at single-phase-earth faults and to the difference of currents in faulty phases at phase-to-phase faults. For one-terminal lines at single-phase-earth faults, neglecting capacitive and load currents, this ratio is 1, and for phase-to-phase faults it equals 1/2. For other cases it is a complex quantity, with the absolute value > 1 for single-phase-earth faults. Its significance grows with the fault resistance Rf. At Rf = 0 this ratio loses its significance for determination of the distance to a fault place. The tangent of the fault quotient angle with a real axis enters into the ultimate expressions for the reactance to fault place and for the fault resistance. The use of such a quotient facilitates reiterative calculations of the distance to a fault place.

The Role of Fault Quotient in Determination of the Distance to a Transmission Line Fault

Riga Technical University, 1 Kronvalda Blvd. 1, Riga, LV-1010, LATVIA

Latvian Journal of Physics and Technical Sciences

The notion of fault quotient refers to single-phase-earth and phase-to-phase faults in one-terminal and two-terminal (double fed), single or parallel power...

The Role of Fault Quotient in Determination of the Distance to a Transmission Line Fault

Published Online: Nov 21, 2008

Page range: 3 - 16

DOI: https://doi.org/10.2478/v10047-008-0021-7

Keywords
distance protection, fault resistance, single-phase-earth fault, phase-to-phase fault

This content is open access.

The Role of Fault Quotient in Determination of the Distance to a Transmission Line Fault

Published Online: Nov 21, 2008

Page range: 3 - 16

DOI: https://doi.org/10.2478/v10047-008-0021-7

Keywordsdistance protection, fault resistance, single-phase-earth fault, phase-to-phase fault

This content is open access.

Keywords
distance protection, fault resistance, single-phase-earth fault, phase-to-phase fault