Method of locating internal arcing in a gas-insulated line and an associated device

Patent metadata

Field	Value
Publication number	US-9702922-B2
Application number	US-201113806099-A
Country	US
Kind code	B2
Filing date	Jun 23, 2011
Priority date	Jun 23, 2010
Publication date	Jul 11, 2017
Grant date	Jul 11, 2017

Abstract

A method and a device for locating internal arcing that occurs in a compartment (CP i ) of a gas-insulated line (L), each compartment being provided with at least one pressure sensor (P i ). The method comprises: triggering pressure measurements in a compartment as soon as the difference between the currents that flow through two current toroids (TC i ) around two adjacent compartments exceeds a threshold value indicating the occurrence of internal arcing in the compartment; calculating a period Δt that separates the time at which the pressure detector began to detect a pressure variation and the time at which the internal arcing occurred; and calculating a distance d that separates the place at which the internal arc is formed from the position of the pressure sensor using the equation d=V/Δt in which V is the speed of sound in the gas.

First claim

The invention claimed is:

1. A method of locating an internal arc in a gas-insulated line consisting of a succession of compartments CP i (i=1, 2, . . . , N) filled with gas, the method being characterized in that, for each compartment CP i being surrounded by a current toroid TC i respectively (i=1, 2, . . . , N) through which there flows a current I i that is identical in the absence of interference from one compartment to another and being provided with at least one pressure sensor P i adapted to measure the pressure of the gas inside the compartment, the method comprises the following steps:
reading (E 1 ), at a sampling frequency, the currents I i that flow through the current toroids;
calculating (E 2 ), at the sampling frequency, current differences I diff/i such that I diff/i =I i+1 −I i , and storing the calculated current differences;
comparing (E 3 ) the stored current differences I diff/i with a current threshold value and, as soon as a current difference is greater than or equal to the threshold value at a time t t :
triggering (E 4 ) a succession of pressure measurements by the pressure sensor P i , and storing the measured pressure values in response to the current difference being greater than or equal to the threshold value;
calculating (E 7 ) from a time variations of the stored pressure measurements a pressure rise time t m at which the pressure measured by the pressure sensor P, begins to increase;
calculating (E 8 ) a period Δt P that is the difference between the times t m and t t ;
calculating (E 5 ) a time t 0 that characterizes the occurrence of internal arcing in the compartment CP i from a time variations of the stored current differences;
calculating (E 6 ) a period Δt i that is the difference between the times t t and t 0 ;
calculating (E 9 ) a period Δt that is the sum of the previously-calculated periods Δ i and Δt P ; and
calculating (E 10 ) the distance d that separates the pressure sensor P i from a place at which a fault occurred using the equation d=V/Δt in which V is the speed of propagation of sound in the gas.

2. A method according to claim 1 , wherein the current toroid TC i surrounds a first end of the compartment CP i and the pressure sensor P i is mounted on an end of the compartment opposite the first end.

3. A method according to claim 1 , wherein a first pressure sensor P i is mounted on the compartment at a first end of the compartment and a second pressure sensor P i is mounted on the compartment at an end of the compartment opposite the first end.

4. A device for locating an internal arc in a gas-insulated line consisting of a succession of compartments CP i (i=1, 2, . . . , N) filled with gas, the device being characterized in that it comprises:
N current toroids TC i (i=1, 2, . . ., N), each surrounding a distinct compartment and having flowing through it a current I i that is identical in the absence of interference from one compartment to another;
N detection processors DC i (i=1, 2, . . . , N), each able to read the current I i flowing through the current toroid TC i and the current I i−1 flowing through the current toroid TC, i−1 and including means for calculating the differences between the currents I i and I i−1 , for storing the calculated current differences, and for delivering a command signal at a time t t , as soon as the difference between the currents I i and I i−1 is greater than or equal to a threshold;
at least one pressure sensor P i mounted on each compartment CP i and adapted to measure the pressure of the gas inside the compartment;
N gas monitoring modules MG i (i=1, 2, . . . , N) each including means adapted to respond to the command signal by triggering successive measurements by the pressure sensor P i of the pressure of the gas contained in the compartment CP i and storing the successive pressure measurements effected in response to the current difference being greater than or equal to the threshold value; and
a supervisory unit adapted to calculate:
from a time variations of the stored pressure measurements, a pressure rise time t m that is the time at which the pressure measured by the pressure sensor P i begins to increase;
a period Δt P that is the difference between the times t m and t t ;
from a time variations of the stored current differences, a time t 0 that characterizes the occurrence of internal arcing in the compartment CP i ;
a period Δt i that is the difference between the times t t and t 0 ;
a period Δt that is the sum of the previously-calculated periods Δt i and Δt P ; and a distance d that separates the pressure sensor P i from a place at which the fault has occurred from the equation d=V/Δt in which V is the speed of propagation of sound in the gas.

5. A device according to claim 4 , wherein the current toroid TC i surrounds a first end of the compartment CP i and a pressure sensor P i is mounted on an end of the compartment opposite the first end.

6. A device according to claim 4 , wherein a first pressure sensor P i is mounted on the compartment at a first end of the compartment, a second pressure sensor P i is mounted on the compartment at an end of the compartment opposite the first end, and the current toroid surrounds the compartment at the center of the compartment.

Assignees

• Juge Patrice
• Granelli Guillaume
• Alstom Technology Ltd

Inventors

• Juge Patrice
• Granelli Guillaume

Classifications

• G01R31/1254

  of gas-insulated power appliances or vacuum gaps (testing switches G01R31/327; detecting electrical or mechanical defects in encased switchgear H02B13/065) · CPC title

• G01R31/08 Primary

  Locating faults in cables, transmission lines, or networks · CPC title

• G01R31/1272

  of cable, line or wire insulation, e.g. using partial discharge measurements (locating faults in cables G01R31/083) · CPC title

• G01R31/085 Primary

  in power transmission or distribution lines, e.g. overhead · CPC title

• G06F17/00

  Digital computing or data processing equipment or methods, specially adapted for specific functions (information retrieval, database structures or file system structures therefor G06F16/00) · CPC title