Method for detecting a fault occurring in a cable
A method for detecting and locating a fault affecting an electrical cable includes the steps of (a) placing a first sensor and a second sensor along the cable, the second sensor being an acoustic sensor; (b) detecting the occurrence of the fault with the first sensor at a first time, and with the second sensor at a second time; (c) taking into account a propagation speed of an acoustic wave generated by the fault; (d) estimating a position of the fault depending on the first time and on the second time, on the basis of the propagation speed resulting from step (c); (e) determining a reference propagation speed depending on the position resulting from step (d) of the fault, and comparing said reference propagation speed with the propagation speed taken into account in step (c); and, (f) depending on the comparison, validating the position resulting from step (d) or reiterating steps (c) to (f) while adjusting, in step (c), the propagation speed taken into account.
1. A method for detecting and locating a fault affecting a cable, the cable being configured to conduct an electrical current, the method comprising:
a) placing a first sensor and a second sensor, the first sensor being able to detect the occurrence of a fault in the cable, the second sensor being able to detect an acoustic wave propagating along the cable, following the occurrence of the fault in the cable;
b) detecting the occurrence of the fault with the first sensor, at a first time, and with the second sensor, at a second time, subsequent or identical to the first time;
c) selecting a propagation speed of the acoustic wave generated by the fault;
d) estimating a position of the fault depending on the first time and on the second time, on the basis of the propagation speed resulting from c);
e) determining a reference propagation speed depending on the position estimated in d) of the fault, and comparing the reference propagation speed with the propagation speed resulting from c); and
f) depending on the comparison,
validating the position resulting from d); or
reiterating c) to f) while adjusting, in c), the propagation speed
wherein, in e), the reference propagation speed is determined using a propagation function describing a variation in the propagation speed of an acoustic wave, in the cable, as a function of the propagation distance of the acoustic wave.
2. The method according to claim 1 , wherein the first sensor is an acoustic sensor, configured to detect the acoustic wave propagating along the cable.
3. The method according to claim 2 , wherein, in d), the position of the fault is estimated by:
di) calculating a time difference between the first time and the second time; and
dii) comparing a distance between the first sensor and the second sensor, along the cable, to a distance obtained by multiplying the propagation speed of the acoustic wave, resulting from c), by the time difference.
4. The method according to claim 2 , wherein, in d), the position of the fault is located between the first sensor and the second sensor.
5. The method according to claim 1 , wherein the first sensor is an electrical sensor, configured to measure an electrical signal propagating along the cable, and a variation generated by the fault in the electrical signal.
6. The method according to claim 5 , wherein, in d), the position is estimated by:
di) calculating a time difference between the first time and the second time; and
dii) multiplying the propagation speed of the acoustic wave, taken into account in c), by the time difference.
7. The method according to claim 1 , wherein, in a reiteration of c) to f), the propagation speed of an iteration corresponds to the reference propagation speed determined in e) of the preceding iteration.
8. A device for detecting and locating the position of a fault in a cable, the cable being configured to conduct an electrical current, the device comprising:
a first sensor, configured to detect the occurrence of a fault in the electrical cable;
a second sensor, configured to detect an acoustic wave propagating along the cable following the occurrence of the fault in the cable; and
a processor, connected to the first sensor and to the second sensor, and configured to execute instructions to implement steps c) to f) of the method according to claim 1 , on the basis of detection signals coming from the first sensor and the second sensor.
9. The device according to claim 8 , wherein the first sensor is a sensor configured to detect an acoustic wave propagating along the cable following the occurrence of the fault in the cable.
10. The device according to claim 8 , wherein the first sensor is an electrical sensor, configured to measure an electrical parameter relative to the current flowing through the cable.
11. The method according to claim 1 , comprising:
determining the reference propagation speed depending on the position estimated in d) of the fault using a variable propagation speed which varies as a function of distance from the fault.