Automatic fault location system

Claim 2

A fault location system for locating a fault associated with one or more conductors of an electric power transmission or distribution system, comprising: a first transducer set for measuring a first voltage (V A ) and a first current (I A ), at a first prescribed location on at least one conductor; a second transducer set for measuring a second voltage (V B ) and a second current (I B ) at a second prescribed location on said at least one conductor; (c) a first relay, coupled to said first transducer set, for generating data (V Af , I Af ), indicative of an amplitude and phase of said first voltage and current; (d) second relay, coupled to said second transducer set, for generating data V Bf , I Bf ) indicative of an amplitude and phase of said second voltage and current; and (e) a fault location estimation processor, coupled to said first and second relays, for generating a fault location parameter m indicative of the location of the fault; wherein m is obtained from one of the following equations: ##EQU8## wherein δ represents a phase difference between said first and second voltages, A is a real number having a value which is a first predetermined function of I Af and a resistance and reactance of said at least one conductor, B is a real number having a value which is a second predetermined function of I Af and said resistance and reactance of said at least one conductor, C is a real number having a value which is a first predetermined function of I Bf and said resistance and reactance of said at least one conductor; and D is a real number having a value which is a fourth predetermined function of I Bf and said resistance and reactance of said at least one conductor.

Claim 3

A fault location system as recited in claim 1, wherein δ is obtained from the equations: ##EQU9## F(δ.sub.k)=b* cos δ.sub.k +a* sin δ.sub.k +C F'(δ.sub.k)=a* cos δ.sub.k -b* sin δ.sub.k a=-C*Re(V.sub.Af)-D*Im(V.sub.Af)-A*Re(V.sub.Bf)-B*Im(V.sub.Bf)+AC+BD b=D*Re(V.sub.Af)-C*Im(V.sub.Af)-B*Re(V.sub.Bf)+A*Im(V.sub.Bf)+BC-AD c=B*Re(V.sub.Af)-A*Im(V.sub.Af)-D*Re(V.sub.Bf)+C*Im(V.sub.Bf).

Claim 4

A fault location system as recited in claim 2, wherein A, B, C, and D are obtained from: A=R*Re(I.sub.Af)-X*Im(I.sub.Af) B=R*Im(I.sub.Af)+X*Re(I.sub.Af) C=R*Re(I.sub.Bf)-X*Im(I.sub.Bf) D=R*Im(I.sub.Bf)+X*Re(I.sub.Bf).

Claim 5

A fault location system for locating a fault associated with one or more conductors of an electric power transmission or distribution system, comprising: (a) a first transducer set for measuring a first voltage (V A ) and a first current (I A ) at a first prescribed location on at least one conductor; (b) a second transducer set for measuring a second voltage (V B ) and a second current (I B ) at a second prescribed location on said at least one conductor; (c) a first relay, coupled to said first transducer set, for generating data (V Af , I Af ) indicative of an amplitude and phase of said first voltage and current; (d) a second relay, coupled to said second transducer set, for generating data (V Bf , I Bf ) indicative of an amplitude and phase of said second voltage and current; (e) a fault location estimation processor, coupled to said first and second relays, for generating a fault location parameter m indicative of the location of the fault and for determining whether compensation is required of parameter m to compensate for long conductors in the electric transmission or distribution system; wherein m is obtained from one of the following equations: ##EQU10## wherein δ represents a phase difference between said first and second voltages, A is a real number having a value which is a first predetermined function of I Af and a resistance and reactance of said at least one conductor, B is a real number having a value which is a second predetermined function of I Af and said resistance and reactance of said at least one conductor, C is a real number having a value which is a first predetermined function of I Bf and said resistance and reactance of said at least one conductor, and D is a real number having a value which is a fourth predetermined function of I Bf and said resistance and reactance of said at least one conductor.

Claim 6

A fault location system for locating a fault associated with one or more conductors of an electric power transmission or distribution system, comprising: (a) a first transducer set for measuring a first voltage (V A ) and a first current (I A ) at a first prescribed location on at least one conductor; (b) a second transducer set for measuring a second voltage (V B ) and a second current (I B ) at a second prescribed location on said at least one conductor; (c) a first relay, coupled to said first transducer set, for generating data (V Af , I Af ) indicative of an amplitude and phase of said first voltage and current; (d) a second relay, coupled to said second transducer set, for generating data (V Bf , I Bf ) indicative of an amplitude and phase of said second voltage and current; (e) a fault location estimation processor, coupled to said first and second relays, for generating a fault location parameter m indicative of the location of the fault and for determining whether compensation is required of parameter m to compensate for long conductors in the electric transmission or distribution system; wherein m is obtained from one of the following equations: ##EQU10## wherein δ represents a phase difference between said first and second voltages, A is a real number having a value which is a first predetermined function of I Af and a resistance and reactance of said at least one conductor, B is a real number having a value which is a second predetermined function of I Af and said resistance and reactance of said at least one conductor, C is a real number having a value which is a first predetermined function of I Bf and said resistance and reactance of said at least one conductor, and D is a real number having a value which is a fourth predetermined function of I Bf and said resistance and reactance of said at least one conductor.

Claim 7

A fault location system as recited in claim 2, wherein said fault location processor determines whether compensation is required to parameter m for compensating for long conductors in the electric transmission or distribution system by computing A, B, C, and D from: A=R.sub.A *Re(I.sub.Af)-X.sub.A *Im(I.sub.Af) B=R.sub.A *Im(I.sub.Af)+X.sub.A *Re(I.sub.Af) C=R.sub.B *Re(I.sub.Bf)-X.sub.B *Im(I.sub.Bf) D=R.sub.B *Im(I.sub.Bf)+X.sub.B *Re(I.sub.Bf) wherein R A , R B , X A , and X B are resistance and reactance values.

Claim 8

A fault location system for locating a fault associated with one or more conductors of an electric power transmission or distribution system, comprising: (a) a first transducer set for measuring a first voltage (V A ) and a first current (I A ) at a first prescribed location on at least one conductor; (b) a second transducer set for measuring a second voltage (V B ) and a second current (I B ) at a second prescribed location on said at least one conductor; (c) a first relay, coupled to said first transducer set, for generating data (V Af , I Af ) indicative of an amplitude and phase of said first voltage and current; (d) a second relay, coupled to said second transducer set, for generating data (V Bf , I Bf ) indicative of an amplitude and phase of said second voltage and current; (e) a fault location estimation processor, coupled to said first and second relays, for generating a fault location parameter m indicative of the location of the fault; and for determining whether compensation is required of parameter m to compensate for shunt elements in the electric transmission or distribution system; wherein m is obtained from one of the following equations: ##EQU11## wherein δ represents a phase difference between said first and second voltages, A is a real number having a value which is a tint predetermined function of I Af and a resistance and reactance of said at least one conductor, B is a real number having a value which is a second predetermined function of I Af and said resistance and reactance of said at least one conductor, C is a real number having a value which is a first predetermined function of I Bf and said resistance and reactance of said at least one conductor, and D is a real number having a value which is a fourth predetermined function of I Bf and said resistance and reactance of said at least one conductor.

Claim 9

A fault location system for locating a fault associated with one or more conductors of an electric power transmission or distribution system, comprising: (a) a first transducer set for measuring a first voltage (V A ) and a first current (I A ) at a first prescribed location on at least one conductor; (b) a second transducer set for measuring a second voltage (V B ) and a second current (I B ) at a second prescribed location on said at least one conductor; (c) a first relay, coupled to said first transducer set, for generating data (V Af , I Af ) indicative of an amplitude and phase of said first voltage and current; (d) a second relay, coupled to said second transducer set, for generating data (V Bf , I Bf ) indicative of an amplitude and phase of said second voltage and current; (e) a fault location estimation processor, coupled to said first and second relays, for generating a fault location parameter m indicative of the location of the fault; and for determining whether compensation is required of parameter m to compensate for shunt elements in the electric transmission or distribution system; wherein m is obtained from one of the following equations: ##EQU11## wherein δ represents a phase difference between said first and second voltages, A is a real number having a value which is a tint predetermined function of I Af and a resistance and reactance of said at least one conductor, B is a real number having a value which is a second predetermined function of I Af and said resistance and reactance of said at least one conductor, C is a real number having a value which is a first predetermined function of I Bf and said resistance and reactance of said at least one conductor, and D is a real number having a value which is a fourth predetermined function of I Bf and said resistance and reactance of said at least one conductor.