Method for monitoring an electrical power supply line comprised in a seismic cable, corresponding system, computer program product and non-transitory computer-readable carrier medium

Abstract

It is proposed a method for monitoring an electrical power supply line comprised in a seismic cable and extending along the seismic cable. The seismic cable includes: a plurality of seismic sensors arranged along the seismic cable, a plurality of controllers arranged along the seismic cable, and an optical transmission line extending along the seismic cable for carrying data signals from or towards the controllers. The electrical power supply line supplies at least one pair of master and slave controllers. The master controller of a given pair of master and slave controllers performs a step of monitoring a portion of the electrical power supply line between the master and slave controllers, by using an optical loop established on a portion of the optical transmission line between the master and slave controllers, and starting from the master controller and passing through the slave controller.

Claims

1. A method for monitoring an electrical power supply line comprised in a seismic cable and extending along said seismic cable, said seismic cable further comprising: a plurality of seismic sensors arranged along the seismic cable, a plurality of controllers arranged along the seismic cable, an optical transmission line extending along said seismic cable for carrying data signals from or towards said controllers, said electrical power supply line supplying at least one pair of master and slave controllers, wherein the method comprises, for at least one given pair of master and slave controllers: the master controller monitoring a portion of said electrical power supply line comprised between said master and slave controllers, by using an optical loop established on a portion of said optical transmission line comprised between said master and slave controllers.

2. The method according to claim 1, wherein the master controller further performs: emitting an optical test signal through the portion of said optical transmission line comprised between said master and slave controllers, receiving an optical return signal supposed to result from a reflection of said test signal by the slave controller, said monitoring the portion of said electrical power supply line being performed as a function of said return signal.

3. The method according to claim 2, wherein the master controller further performs: determining an effective propagation duration elapsed between an emission instant of said optical test signal and a reception instant of said optical return signal; a first step of comparing the effective propagation duration with a first reference propagation duration which is as a function of a predetermined distance separating the master and slave controllers; obtaining a first piece of monitoring information as a function of the result of said first step of comparing.

4. The method according to claim 3, wherein said at least one given pair of master and slave controllers are separated by a cable portion comprising a plurality of cable sections, each cable section having an optical connector on both ends of said cable section, and wherein the master controller further performs, if the effective propagation duration is different from the first reference propagation duration: a second step of comparing the effective propagation duration with at least one second reference propagation duration, each being as a function of a predetermined distance separating said master controller and one of said optical connectors of the cable portion; obtaining a second piece of monitoring information as a function of the result of said second step of comparing.

5. The method according to claim 3, wherein the master controller further performs: processing said first piece of monitoring information and/or said second piece of monitoring information, delivering a positive or negative decision to stop supplying said slave controller via the portion of said electrical power supply line, as a function of the result of said step of processing.

6. The method according to claim 3, wherein the master controller further performs sending said first second piece of monitoring information and/or said second piece of monitoring information to a remote control system, accompanied with an identifier of said master controller, so as to take a positive or negative decision to stop supplying on said electrical power supply line.

7. A system for monitoring an electrical power supply line included in a seismic cable and extending along said seismic cable, said seismic cable further including: a plurality of seismic sensors arranged along the seismic cable, a plurality of controllers arranged along the seismic cable, an optical transmission line extending along said seismic cable for carrying data signals from or towards said controllers, said electrical power supply line supplying in cascade a succession of pairs of master and slave controllers on a succession of portions of said electrical power supply line, wherein the system comprises, for at least one given pair of master and slave controllers: optical means arranged to cooperate with a portion of said optical transmission line comprised between said master and slave controllers so as to form an optical loop starting from the master controller and passing through the slave controller, and means for monitoring, using said optical loop to monitor a portion of said electrical power supply line comprised between the master and slave controllers.

8. The system according to claim 7, wherein said optical means comprise: on the master controller side: an optical source arranged for generating an optical test signal through the portion of said optical transmission line, an optical sensor arranged for receiving an optical return signal supposed to result from a reflection of said optical test signal by light signal reflecting means comprised within the slave controller, on the slave controller side: said light signal reflecting means arranged for reflecting said optical test signal coming from the master controller.

9. The system according to claim 8, wherein said means for monitoring comprise means for processing the optical return signal received by the optical sensor.

10. The system according to claim 8, wherein said light signal reflecting means comprise a device having a return loss coefficient which is upper than −15 dB.

11. The system according to claim 10, wherein said device belongs to the following group: an optical reflective mirror; a disconnected right-cleaved physical contact optical connector.

12. The system according to claim 7, wherein said at least one given pair of master and slave controllers are separated by a cable portion comprising a plurality of cable sections, each cable section comprising an optical connector on both ends of said cable section having a return loss coefficient which is upper than −15 dB when disconnected.

13. The system according to claim 12, wherein each optical connector is a right-cleaved physical contact optical connector.

14. The system according to claim 7, wherein the seismic cable belongs to the group comprising: a seismic streamer; an ocean bottom cable.

15. A non-transitory computer-readable carrier medium storing a computer program product comprising a computer program code instructions which, when executed on a computer or a processor, implement a method for monitoring an electrical power supply line comprised in a seismic cable and extending along said seismic cable, said seismic cable further comprising: a plurality of seismic sensors arranged along the seismic cable, a plurality of controllers arranged along the seismic cable, an optical transmission line extending along said seismic cable for carrying data signals from or towards said controllers, said electrical power supply line supplying at least one pair of master and slave controllers, wherein, for at least one given pair of master and slave controllers, the method comprises: the master controller monitoring a portion of said electrical power supply line comprised between said master and slave controllers, by using an optical loop established on a portion of said optical transmission line comprised between said master and slave controllers.

Description

5. LIST OF FIGURES

(1) Other features and advantages of embodiments of the invention shall appear from the following description, given by way of an indicative and non-exhaustive examples and from the appended drawings, of which:

(2) FIG. 1, already described with reference to the prior art, presents an example of network of seismic cables towed by a seismic vessel;

(3) FIG. 2, already described with reference to the prior art, illustrates in detail the classic structure of a portion of seismic cable of FIG. 1;

(4) FIG. 3 provides, in the form of function blocks, a schematic illustration of the system according to a particular embodiment of the invention;

(5) FIG. 4 provides an example of chronograms showing the time evolution of the optical emission and reception level measured by a master controller to illustrate the principle of detecting a failure location on the electrical power supply line comprised between a master controller and a slave controller;

(6) FIG. 5 is a flowchart of a particular embodiment of the method according to the invention, implemented by a master controller;

(7) FIG. 6 shows the simplified structure of a controller according to a particular embodiment of the invention.

6. DETAILED DESCRIPTION

(8) In all of the figures of the present document, identical elements and steps are designated by the same numerical reference sign. The invention relies on the use of a safety optical loop to carry out the monitoring of an electrical power supply line within a seismic cable.

(9) The seismic cable according to the invention comprises: a plurality of seismic sensors arranged along the seismic cable, a plurality of controllers arranged along the seismic cable, an electrical transmission line (not shown on FIGS. 3 to 6) extending along the seismic cable for conveying electrical data signals between controllers and nodes, an optical transmission line extending along the seismic cable for conveying optical data signals from or towards the controllers, and from or towards the seismic vessel. an electrical power supply line supplying power to the controllers.

(10) The electrical transmission line typically comprises at least one pair of copper wires. It conveys electrical data comprising notably, but not exclusively, seismic data and test data between the controllers and nodes. The electrical transmission line is further used for powering the nodes arranged on the cable with a low voltage power.

(11) The optical transmission line typically comprises one or several optical fibers which convey optical data comprising notably, but not exclusively, seismic data and control data from master controller to slave controller and/or from slave controller to master controller. The optical transmission line typically cooperates with an optical light source (hereafter referenced as “Tx”) comprised in the master controller and with an optical light receiver (hereafter referenced as “Rx”) comprised in the slave controller, used respectively for optical data transmission and reception.

(12) FIG. 3 illustrates a particular embodiment of the monitoring system according to the invention, implemented in a portion 220 of a seismic cable, for example the seismic cable 100 illustrated on FIG. 1. The seismic cable portion 220 is comprised between a master controller C.sub.1 and a slave controller C.sub.2, the master controller C.sub.1 managing the power supply of the slave controller C.sub.2.

(13) The seismic cable portion 220 is divided into a set of successive cable sections dedicated to data acquisition, referenced S.sub.10, S.sub.20, S.sub.30, . . . S.sub.p. Each cable section may comprise a plurality of nodes (not shown on the figures) distributed along the cable at intervals that are not necessarily regular. As explained above, a node is adapted for collecting seismic data issued from a given associated set of sensors 210 and to digitize them before sending them, via the controllers, to the central unit situated on the seismic vessel. The seismic sensors 210, such as hydrophones or geophones or accelerometers, are arranged along the section and are adapted for detecting acoustic signals.

(14) Each cable section comprises an optical connector on both ends, adapted for allowing a mechanical and optical interconnection with another cable section or with a controller. The cable section S.sub.10 has the optical connectors O10.sub.1, O10.sub.2. The cable section S.sub.20 has the optical connectors O20.sub.1, O20.sub.2. The cable section S.sub.30 has the optical connectors O30.sub.1, O30.sub.2. The cable section S.sub.p has the optical connectors OP.sub.1, OP.sub.2.

(15) The master controller C.sub.1 has a connector on each of its ends, namely the connectors OM.sub.1, OM.sub.2. The slave controller C.sub.2 has a connector on each of its ends, namely the connectors OS.sub.1, OS.sub.2. The connector OM.sub.2 is adapted to mat with the connector O10.sub.1 of the first section S.sub.10 of the cable portion 220, whereas the connector OM.sub.1 is adapted to mat with a connector of a section of another cable portion not shown on the figure. The connector OS.sub.1 is adapted to mat with the connector Op.sub.2 of the last section S.sub.p of the cable portion 220, whereas the connector OS.sub.2 is adapted to mat with a connector of a section of another cable portion not shown on the figure.

(16) It is considered below that two connectors connected (of two sections or of a controller and a section), form a pair of connectors.

(17) According to an advantageous feature, the optical connectors are of the type that have a return loss coefficient upper than −15 dB when they are disconnected (or not connected). For example, each optical connector illustrated on FIG. 3 is right-cleaved physical contact optical connectors (for a right-cleaved physical contact, the contact area between two connectors coupled is polished without angle, in opposition with the connectors APC (“Angled Physical Contact”) where the contact area between two connectors is polished with an angle of 8 or 9 degrees. On APC connectors, the return loss is lower than −30 dB even if the optical connector is disconnected).

(18) It should be noted that each cable section comprises seismic sensors and nodes distributed along the cable at intervals that are not necessarily regular. A node is adapted for collecting and processing seismic data issued from a given set of sensors 210, then to sent them to the central unit situated on the seismic vessel via the controllers. The nodes are not shown on the figures to avoid overburdening them.

(19) The seismic cable portion 220 further comprises a portion of the optical transmission line, referenced 240, and a portion of the electrical power supply line, referenced 250.

(20) The operating principle of the invention is based on the addition of optical means arranged to cooperate with the portion 220 of the optical transmission line comprised between the pair of master and slave controllers C.sub.1, C.sub.2 so as to form an optical loop, starting from the master controller C.sub.1 and passing through the slave controller C.sub.2. The optical means according to the invention comprises: on the master controller side (C.sub.1): an optical source 310 (also referenced as “Tx” on the figure) arranged for generating an optical test signal 315 through the portion of the optical transmission line, an optical sensor 320 (also referenced as “Rx” on the figure), such as a photodiode, arranged for receiving a optical return signal 325 supposed to result from a reflection of the optical test signal by light signal reflecting means 360 comprised within the slave controller C.sub.2, light beam splitter 330, arranged between the optical source 310 and the portion 240 of the optical transmission line, for deviating the return signal, coming from the slave controller C.sub.2, onto the optical sensor 320, on the slave controller side (C.sub.2): light signal reflecting means 360 (such as an optical reflective mirror or a disconnected optical fiber connector for example), arranged at the end of optical line, for reflecting the optical test signal coming from the master controller C.sub.1, light beam splitter 350, arranged between the portion 240 of the optical transmission line and an optical receiver 340, for deviating the test signal, coming from the master controller C.sub.1, onto the light signal reflecting means 360.

(21) The optical loop is designed to operate as follows. In operation, the optical source 310, comprised in the master controller C.sub.1, injects a light pulse 315 of known amplitude, acting as a test signal, over the portion 240 of the optical transmission line. If the cable portion 220 has no defect (i.e. is not open or defective), the light pulse 315 goes through the optical transmission line portion 240 towards the slave controller C.sub.2, takes a deflection via the light beam splitter 350 in order to be directed to the optical reflective mirror 360. The light pulse 315 reflected by the mirror 360 forms a return signal that is then injected over the portion 240 of the optical transmission line via the light beam splitter 350. The return signal 325 goes through the optical transmission line portion 240 towards the master controller C.sub.1, and takes a deflection via the light beam splitter 330 in order to be directed to the optical sensor 320.

(22) The master controller C.sub.1 further comprises a monitoring unit 380 that uses this optical loop established on the portion 240 of optical transmission line, to monitor the portion 250 of the electrical power supply line comprised between the master C.sub.1 and slave C.sub.2 controllers. If the optical loop is detected as being closed, the monitoring unit 380 considers the portion 250 of the electrical power supply line has no defect. If the optical loop is detected as being open, the monitoring unit 380 considers the portion 250 of the electrical power supply line defective.

(23) The principle of the invention is therefore of checking, thanks to the optical loop, if the seismic cable is not open or defected by checking that the optical transmission line portion is not cut.

(24) The electrical power supply line monitoring is carried out by means of a processing of the optical return signal, described in detail below in relation with FIGS. 4 and 5. A processing unit comprised in the monitoring unit 380 performs this return signal processing.

(25) An optical circulator is rather used as a light beam splitter when the optical transmission line is based on a bidirectional communications on one fiber schema and a coupler (cooperating with an isolator) is rather used as a light beam splitter when the optical transmission line is based on a unidirectional communications schema.

(26) FIG. 5 is a flowchart of a particular embodiment of the method according to the invention, implemented by the master controller C.sub.1 of FIG. 3. This algorithm more particularly synthesizes the running of the different steps needed for monitoring the portion 250 of the electrical power supply line of a seismic cable.

(27) Using an Optical Loop

(28) At the step 51, the master controller C.sub.1 sends, via the optical source 310, the optical controller test signal 315 through the portion 240 of the optical transmission line between the master controller C.sub.1 and slave controller C.sub.2. An example of test signal emitted by the controller C.sub.1 is represented on the chronogram (A) of FIG. 4.

(29) At the step 52, the master controller C.sub.1 receives, via the optical sensor 320, an optical return signal 325. This return signal 325 is supposed to result from a reflection of the optical test signal 315 by the slave controller, and more precisely by the optical reflective mirror 360 comprised in the slave controller C.sub.2. An example of a return signal received by the controller C.sub.1 is represented on the chronogram (B) of FIG. 4. The return signal illustrated here is the reference optical signal resulting from the reflection of the optical test signal on the reflective mirror 360 arranged at the end of optical line. The reflective mirror 360 has typically a return loss coefficient typically upper than −15 dB.

(30) The master controller C.sub.1 then processes the optical return signal 325.

(31) At the step 53, the master controller C.sub.1 determines the effective duration (T) elapsed between an emission instant of the test signal 315 and a reception instant of the optical return signal 325, in order to compare it with a reference duration of a first type, hereafter referenced T.sub.ref.

(32) The reference duration of the first type T.sub.ref is understood to be the expected propagation duration necessary to an optical signal to propagate on the optical loop, starting from the master controller C.sub.1, passing through the slave controller C.sub.2 and coming back to the master controller C.sub.1.

(33) In a general manner, the optical loop is characterized by a reference duration of the first type T.sub.ref defined as follow:
T.sub.ref=2L/nc
with: L, the distance comprised between the controllers C.sub.1 and C.sub.2; n, the index of refraction of the optical fiber concerned in the optical transmission line; c, the speed of light in the medium of the index n (typically c=3.Math.10.sup.8 m.Math.s.sup.−1).

(34) At the step 54, the master controller C.sub.1 makes a check to see if the effective duration T determined in the previous step is equal to the reference duration of the first type T.sub.ref.

(35) If the effective duration T is equal to the reference duration of the first type T.sub.ref, the master controller C.sub.1 considers that the portion 250 of the electrical line supply line has no failure. Indeed, a positive result of the check step means that the optical loop is closed and the controller master controller C.sub.1 can propagate or continues to propagate the high voltage to the slave controller C.sub.2 via the electrical line portion 250.

(36) If the effective duration T is different from the reference duration of the first type T.sub.ref, the master controller C.sub.1 considers that the portion 250 of the electrical line supply line is open or defective. Indeed, a negative result of the check step means that the optical loop is open and the controller master controller C.sub.1 must stop supplying the slave controller C.sub.2 or not propagate the high voltage to the slave controller C.sub.2 via the electrical line portion 250.

(37) At the step 55, the master controller C.sub.1 generates a first piece of monitoring information as a function of the result of the step 54: in case of positive result (T=Tref), the electrical power supply line is detected as operational, in case of negative result (T≠Tref), the electrical power supply line is detected as defective.

(38) In other words, this first piece of monitoring information is used to know if the electrical line portion 250 is considered as being defective or not defective.

(39) Using an Optical Sub-loop

(40) A negative result of the step 54 means that either no optical return signal has been detected by the optical sensor 320 or the optical return signal 325 detected by the optical sensor 320 does not result from a reflection of the optical test signal 315 by the slave controller C.sub.2, but results from a reflection of the optical test signal 315 by one of the pairs of connected optical connectors (OM.sub.2-O10.sub.1 (called P.sub.1); O10.sub.2-O20.sub.1 (called P.sub.2); O20.sub.2-O30.sub.1 (called P.sub.3); O30.sub.2-O40.sub.1 (called P.sub.4) . . . Op.sub.t-OS.sub.1 (called P.sub.m)) of the cable portion 220. In the both cases, the electrical line portion 250 is considered as being open or defective.

(41) The master controller C.sub.1 makes, at the step 56, a comparison between the effective duration T determined in the step 53 (i.e. duration elapsed between the emission instant of the test signal 315 and the reception instant of the optical return signal 325) and reference durations of a second type, hereafter referenced reference durations T.sub.x.

(42) A reference duration of the second type T.sub.x is understood to be the propagation duration necessary to an optical signal to propagate on an optical sub-loop starting from the master controller C.sub.1, passing through the pair of optical connector P.sub.x, and coming back to the master controller C.sub.1.

(43) In a general manner, the optical sub-loop is characterized by a reference duration of the second type T.sub.x defined as follow:
T.sub.x=2L.sub.x/nc
with: L.sub.x, the distance comprised between the controllers C.sub.1 and the optical connector of index x, with 1≦x≦m, x being an integer comprised between 1 and m being the number of pairs of connected optical connectors arranged on the optical transmission line portion; n, the refractive index of the optical fiber concerned in the optical transmission line; c, the speed of light in the medium of the refractive index n (typically c=3.Math.10.sup.8 m.Math.s.sup.−1).

(44) Indeed, when an optical right cleaved physical contact connector is disconnected on the optical transmission line portion 240, this last has the capacity of reflecting at least partially the optical test signal 315 sent by the optical source 310.

(45) It should be noted that with other types of optical connectors like angle cleaved physical contact connectors (APC connectors) or expanded beam connectors, the signal reflected by the connector is very low (<−50 dB or −30 dB) that which is difficult to detect with standard components used for transmission, and this value is the same as the connector is connected or disconnected. It should be noted that the optical return signal to be take into account by the master controller C.sub.1 for the signal processing is the one that results from a reflection on the last optical connector placed slave along the optical transmission line portion. Due to the presence of a plurality of optical connectors, and so the plurality of return signals, it is important to note that only the last return signal received by the controller C.sub.1 is taken into account in the processing.

(46) The chronogram (C) of FIG. 4 illustrates the reception level of the optical return signals received by master controller C1 and that results from reflections of the test signal 315 on the pairs of optical connectors P.sub.1, P.sub.2 et P. The signals 401 and 402 results from a reflection of the test signal by the pairs of connected optical connectors P.sub.1, P.sub.2 respectively. The return signal 403 is the last return signal received by the optical sensor 320. It results from a reflection of the test signal by the pair of optical connector P.sub.x which is the last slave connector capable of reflecting the optical signal.

(47) It should be noted that when a right-cleaved physical contact optical connector is disconnected, it has a return loss level (loss of optical signal power resulting from the reflection caused by a discontinuity) (typically upper than −15 dB), which is much higher than the same optical connector but connected (typically equal to −30 dB).

(48) The effective duration T determined in the step 53 is then compared with the reference durations of the second type T.sub.1, T.sub.2, T.sub.3, . . . , T.sub.m.

(49) If the master controller C.sub.1 detects that the effective duration T determined in step 53 for the last return signal received is identical to the reference duration of the second type T.sub.3 for example, this means that a failure or an opening has been detected and located slave the third pair of optical connector P.sub.3 (x=3) on the cable portion 220.

(50) At the step 57, the master controller C.sub.1 generates a second piece of information relative to the location of a failure detected on the electrical power supply line comprised between the two controllers C.sub.1 and C.sub.2.

(51) The principle here is thus of detecting the furthest slave optical sub-loop not open in order to provide an additional piece of information on the location of a failure detected on the seismic cable.

(52) At the step 58, the master controller C.sub.1 then delivers a decision to stop supplying the slave controller C.sub.2 via the portion 250 of the electrical power supply line as a function of the first piece of monitoring information and/or the second piece of monitoring information. Therefore, it is possible not only to stop supplying the slave controller C.sub.2 if the portion of electrical power supply line is detected as defective, but it is also possible to have a piece of information on the location of the failure detected on the electrical power supply line.

(53) It should be noted that the decision-making process performed at the step 58 can be implemented either by the master controller C.sub.1 as described above or by a remote control system. In the second embodiment, the processing of monitoring information can be carried out at a remote location, for example by a control system placed on-board the 115 vessel, to take a decision to stop supplying the electrical power supply line. However, a step of sending the first second piece of monitoring information and/or the second piece of monitoring information to a remote control system must be done by the controller C.sub.1 prior the execution of step 58. An identifier enables the remote control system to identify the master controller C.sub.1 concerned can be also sent with the monitoring information.

(54) In addition, it should be noted that the method described above can be executed either before starting to supply the electrical power supply line (at seismic cable level or at seismic cable portion level) or during operation, for example implemented at regular time interval during optical data communications.

(55) It should be noted that the technique of monitoring according to the invention can be implemented by a master controller for which the slave controller is placed immediately following (or preceding) the master controller along the seismic. But it can also be implemented by a master controller for which the slave controller is not the immediate successive (or preceding) controller but a following (or preceding) controller separated from the slave controller by at least one controller.

(56) It should be further noted that the technique of monitoring according to the invention can be implemented in a bidirectional way. Indeed, the power supply can be carried out from a master concentrator placed at cable end side towards a slave concentrator placed nearer the seismic vessel, and vice versa.

(57) FIG. 6 shows the simplified structure of a monitoring device 70 according to a particular embodiment of the invention. The monitoring device 70 can be the monitoring unit 380 comprised in the master controller C.sub.1 of FIG. 3 for example.

(58) The monitoring device 70 comprises a non-volatile memory 73 (e.g. a read-only memory (ROM) or a hard disk), a volatile memory 71 (e.g. a random access memory or RAM) and a processor 72. The non-volatile memory 73 is a non-transitory computer-readable carrier medium. It stores executable program code instructions, which are executed by the processor 72 in order to enable implementation of the method described above in relation with FIG. 5 (method for monitoring an electrical power supply line comprised in a seismic cable).

(59) Upon initialization, the aforementioned program code instructions are transferred from the non-volatile memory 73 to the volatile memory 71 so as to be executed by the processor 72. The volatile memory 71 likewise includes registers for storing the variables and parameters required for this execution. The processor 72 receives an optical return signal (referenced 74) supposed to result from a reflection of a test signal by the slave controller and carries out the electrical power supply line monitoring as a function of the return signal (corresponding to the steps 52 to 58).

(60) According to the program code instructions, the processor 72 executes the program code instructions allowing to the device to deliver a decision 75 to stop supplying the electrical power supply line as a function of the return signal 74.

(61) All the steps of the above monitoring method can be implemented equally well: by the execution of a set of program code instructions executed by a reprogrammable computing machine such as a PC type apparatus, a DSP (digital signal processor) or a microcontroller. This program code instructions can be stored in a non-transitory computer-readable carrier medium that is detachable (for example a floppy disk, a CD-ROM or a DVD-ROM) or non-detachable; or by a dedicated machine or component, such as an FPGA (Field Programmable Gate Array), an ASIC (Application-Specific Integrated Circuit) or any dedicated hardware component.

(62) It should be noted that the invention is not limited to a purely software-based implementation, in the form of computer program instructions, but that it can also be implemented in hardware form or any form combining a hardware portion and a software portion.

(63) Although the present disclosure has been described with reference to one or more examples, workers skilled in the art will recognize that changes may be made in form and detail without departing from the scope of the disclosure and/or the appended claims.

(64) The exemplary embodiment here above described is applied to marine seismic exploration using seismic streamers. The invention of course is not limited to this particular field of application and can be applied to other field of application like marine seismic exploration using Ocean Bottom Cables (OBC) for seabed acquisition, for example.

(65) An exemplary embodiment of the present disclosure provides a technique for monitoring an electrical power supply line comprised in a seismic cable that avoids the use of an electrical safety loop.

(66) An exemplary embodiment of the present disclosure provides a technique of this kind that offers a seismic cable with a lightered and reduced size structure.

(67) An exemplary embodiment of the present disclosure provides a technique of this kind that offers a cost-effective seismic cable.

(68) An exemplary embodiment of the present disclosure provides a technique of this kind that relies solely on seismic cable architecture classically used.

(69) Although the present disclosure has been described with reference to one or more examples, workers skilled in the art will recognize that changes may be made in form and detail without departing from the scope of the disclosure and/or the appended claims.