US 5,661,664 A · One-terminal data fault location system and process for locating a fault

Abstract

A one-terminal process for locating a fault associated with a transmission system is disclosed. The process is based on the principle fault sequence can be determined by a distribution factor in positive faults may be any defect among phases or ground. The process begins by one end of a transmission line. If the data is oscillographic data, measured data is in phasor form, or after phasors have been calculated determined. Thereafter, a decision is made whether the pre-fault data data is sound, an equation is selected to calculate the fault location decision is made whether the phase is a three-phase fault. Then, a employed to compensate for the fault through a resistance by measuring part of the apparent line impedance. If the fault is not a three-phase formula is not employed and the appropriate equation is selected for the fault location parameter. Accurate fault location techniques for also disclose. The system is insensitive to the zero sequence current information about the system source impedances is required.

Claims23

Dependent claims

A process for locating a fault associated with one or more conductors of a multi-phase electric power transmission or distribution system, said fault being one of the following group of fault types:

phase-to-ground, phase-to-phase-to-ground, phase-to-phase, and phase-to-phase-to-phase;
said process comprising the steps of:
(a) obtaining a voltage phasor (V.sub.Af) and a current phasor (I.sub.sf), said voltage phasor being indicative of an amplitude and phase associated with a voltage waveform at a first prescribed location and said current phasor being indicative of an amplitude and phase associated with a current waveform at said first prescribed location;
(b) generating a fault location parameter m indicative of the location of the fault, wherein said fault location parameter is generated on the basis of at least one of the following equations:
(1) for a phase-to-ground fault, ##EQU38## wherein V.sub.Afa represents a measured phase a fault voltage;
I.sub.sf2 represents a negative sequence fault current;
I.sup.F.sub.sfa represents a measured phase a fault current compensated with a zero sequence current;
R.sub.l1 represents a positive sequence line resistance;
X.sub.l1 represents a positive sequence line reactance;
and .DELTA.I.sub.s1 represents a superimposed positive sequence current;
(2) for a phase-to-phase-to-ground fault, ##EQU39## wherein V.sub.Afbc represents a measured phase b to phase c fault voltage;
I.sub.sfbc represents a phase b to phase c fault current;
and .DELTA.I.sub.sbc represents a phase b to phase c superimposed fault current;
(3) for a phase-to-phase fault, ##EQU40## (4) for a phase-to-phase-to-phase fault, ##EQU41## wherein I.sub.sfa represents a phase a fault current;
and .DELTA.I.sub.sa represents a phase a superimposed fault current.

12 more elements

A system for locating a fault associated with one or more conductors of a multi-phase electric power transmission or distribution system, said fault being one of the following group of fault types:

phase-to-ground, phase-to-phase-to-ground, phase-to-phase, and phase-to-phase-to-phase, comprising:
(a) means for obtaining a voltage phasor (V.sub.Af) and a current phasor (I.sub.sf), said voltage phasor being indicative of an amplitude and phase associated with a voltage waveform at a first prescribed location and said current phasor being indicative of an amplitude and phase associated with a current waveform at said first prescribed location;
and
(b) means for generating a fault location parameter m indicative of the location of the fault, wherein said fault location parameter is generated on the basis of at least one of the following equations:
(1) for a phase-to-ground fault, ##EQU42## wherein V.sub.Afa represents a measured phase a fault voltage;
I.sub.sf2 represents a negative sequence fault current;
I.sup.F.sub.sfa represents a measured phase a fault current compensated with a zero sequence current;
R.sub.l1 represents a positive sequence line resistance;
X.sub.l1 represents a positive sequence line reactance;
and .DELTA.I.sub.s1 represents a superimposed positive sequence current;
(2) for a phase-to-phase-to-ground fault, ##EQU43## wherein V.sub.Afbc represents a measured phase b to phase c fault voltage;
I.sub.sfbc represents a phase b to phase c fault current;
and .DELTA.I.sub.sbc represents a phase b to phase c superimposed fault current;
(3) for a phase-to-phase fault, ##EQU44## (4) for a phase-to-phase-to-phase fault, ##EQU45## wherein I.sub.sfa represents a phase a fault current;
and .DELTA.I.sub.sa represents a phase a superimposed fault current.

12 more elements

An electric power transmission or distribution system, comprising:

(a) a plurality of conductors on which a fault could occur;
(b) means for obtaining a voltage phasor (V.sub.Af) and a current phasor (I.sub.sf), said voltage phasor being indicative of an amplitude and phase associated with a voltage waveform at a first prescribed location and said current phasor being indicative of an amplitude and phase associated with a current waveform at said first prescribed location, said means for obtaining a voltage phasor (V.sub.Af) and a current phasor (I.sub.sf) comprising a member of the group consisting of a protective relay, voltage and current transformers, a microprocessor, and an oscillograph;
(c) means for generating a fault location parameter m indicative of the location of the fault, wherein said fault location parameter is generated on the basis of at least one of the following equations:
(1) for a phase-to-ground fault, ##EQU46## wherein V.sub.Afa represents a measured phase a fault voltage;
I.sub.sf2 represents a negative sequence fault current;
I.sup.F.sub.sfa represents a measured phase a fault current compensated with a zero sequence current;
R.sub.l1 represents a positive sequence line resistance;
X.sub.l1 represents a positive sequence line reactance;
and .DELTA.I.sub.s1 represents a superimposed positive sequence current;
(2) for a phase-to-phase-to-ground fault, ##EQU47## wherein V.sub.Afbc represents a measured phase b to phase c fault voltage;
I.sub.sfbc represents a phase b to phase c fault current;
and .DELTA.I.sub.sbc represents a phase b to phase c superimposed fault current;
(3) for a phase-to-phase fault, ##EQU48## (4) for a phase-to-phase-to-phase fault, ##EQU49## wherein I.sub.sfa represents a phase a fault current;
and .DELTA.I.sub.sa represents a phase a superimposed fault current.

11 more elements

A system for locating a fault associated with one or more conductors of a multi-phase electric power transmission or distribution system, said fault being one of the following group of fault types:

phase-to-ground, phase-to-phase-to-ground, phase-to-phase, and phase-to-phase-to-phase, comprising:
(a) means comprising at least one of the following:
(i) a protective relay;
(ii) voltage and current transformers;
(iii) a microprocessor relay;
and, (iv) an oscillograph for obtaining a voltage phasor (V.sub.Af) and a current phasor (I.sub.sf), said voltage phasor being indicative of an amplitude and phase associated with a voltage waveform at a first prescribed location and said current phasor being indicative of an amplitude and phase associated with a current waveform at said first prescribed location;
and
(b) fault locating means, operatively coupled to said means for obtaining a voltage phasor (V.sub.Af) and a current phasor (I.sub.sf), for generating a fault location parameter m indicative of the location of the fault, wherein said fault location parameter is generated on the basis of at least one of the following equations:
(1) for a phase-to-ground fault, ##EQU50## wherein V.sub.Afa represents a measured phase a fault voltage;
I.sub.sf2 represents a negative sequence fault current;
I.sup.F.sub.sfa represents a measured phase a fault current compensated with a zero sequence current;
R.sub.l1 represents a positive sequence line resistance;
X.sub.l1 represents a positive sequence line reactance;
and .DELTA.I.sub.s1 represents a superimposed positive sequence current;
(2) for a phase-to-phase-to-ground fault, ##EQU51## wherein V.sub.Afbc represents a measured phase b to phase c fault voltage;
I.sub.sfbc represents a phase b to phase c fault current;
and .DELTA.I.sub.sbc represents a phase b to phase c superimposed fault current;
(3) for a phase-to-phase fault, ##EQU52## (4) for a phase-to-phase-to-phase fault, ##EQU53## wherein I.sub.sfa represents a phase a fault current;
and .DELTA.I.sub.sa represents a phase a superimposed fault current.

16 more elements

An electric power transmission or distribution system, comprising:

(a) a plurality of conductors on which a fault could occur;
(b) means for obtaining a voltage phasor (V.sub.Af) and a current phasor (I.sub.sf), said voltage phasor being indicative of an amplitude and phase associated with a voltage waveform at a first prescribed location and said current phasor being indicative of an amplitude and phase associated with a current waveform at said first prescribed location, said means for obtaining a voltage phasor (V.sub.Af) and a current phasor (I.sub.sf) comprising at least one of the following:
a protective relay, voltage and current transformers, a microprocessor, and an oscillograph;
(c) fault locating means, operatively coupled to said means for obtaining a voltage phasor (V.sub.Af) and a current phasor (I.sub.sf), for generating a fault location parameter m indicative of the location of the fault, wherein said fault location parameter is generated on the basis of at least one of the following equations:
(1) for a phase-to-ground fault, ##EQU54## wherein V.sub.Afa represents a measured phase a fault voltage;
I.sub.sf2 represents a negative sequence fault current;
I.sup.F.sub.sfa represents a measured phase a fault current compensated with a zero sequence current;
R.sub.l1 represents a positive sequence line resistance;
X.sub.l1 represents a positive sequence line reactance;
and .DELTA.I.sub.s1 represents a superimposed positive sequence current;
(2) for a phase-to-phase-to-ground fault, ##EQU55## wherein V.sub.Afbc represents a measured phase b to phase c fault voltage;
I.sub.sfbc represents a phase b to phase c fault current;
and .DELTA.I.sub.sbc represents a phase b to phase c superimposed fault current;
(3) for a phase-to-phase fault, ##EQU56## (4) for a phase-to-phase-to-phase fault, ##EQU57## wherein I.sub.sfa represents a phase a fault current;
and .DELTA.I.sub.sa represents a phase a superimposed fault current.

12 more elements

Dependencies are inferred from the claim text.

One-terminal data fault location system and process for locating a fault

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One-terminal data fault location system and process for locating a fault

Life of this patent

Abstract

Claims23