Automated system and method for testing the efficacy and reliability of distributed temperature sensing systems

An automated method for testing the reliability and the efficacy of a distributed sensing system deployed on a structure to be monitored, the method comprising the steps of:

• (a) emitting from a distributed sensing unit pulses of light through a sensing line formed by at least one fibre optic sensing cable laid out on or along a structure to be monitored and at least one fibre optic test cable optically coupled to the at least one sensing cable;
• (b) actuating at least one device arranged relative to the at least one test cable so as to induce a change in the at least one physical parameter associated with the at least one test cable;
• the at least one physical parameter associated with the at least one test cable being selected from the group consisting of:
• (i) temperature;
• (ii) strain;
• and (iii) temperature and strain;
• (c) receiving, at the distributed sensing unit, backscattered light signals associated with locations along the sensing line;
• (d) deriving from the light signals received the at least one physical parameter associated with locations along the sensing line;
• (e) determining whether a change in the at least one physical parameter associated with the sensing line at a location thereof has been detected by the distributed sensing unit within a predetermined time period;
• (f) triggering an alarm condition indicative of the occurrence of a malfunction in the distributed sensing system, if no change has been detected within the predetermined time period;
• (g) if a change has been detected within the predetermined time period, determining whether the change detected is associated with the at least one test cable;
• (h) calculating the reaction time of the distributed sensing system, if the change detected is associated with the at least one test cable;
• and
• (I) triggering an alarm condition indicative of the occurrence of a sensing event at a location along the structure being monitored, if the change detected is associated with the at least one sensing cable.

A distributed sensing system comprising:

• at least one fibre optic sensing cable laid out on or along a structure to be monitored;
• a distributed sensing unit for sensing along a sensing line at least one physical parameter associated with the sensing line at a location thereof;
• the at least one physical parameter being selected from the group consisting of:
• (a) temperature;
• (b) strain;
• and (c) temperature and strain;
• the distributed sensing system being optically coupled to the at least one sensing cable;
• at least one fibre optic test cable optically coupled to the at least one sensing cable to form the sensing line;
• at least one device arranged relative to the at least one test cable to induce a first change in the at least one physical parameter associated with the at least one test cable;
• the first change being detectable by the distributed sensing unit;
• a controller configured for autonomously actuating the at least one change-inducing device to thereby test the efficacy and reliability of the distributed sensing unit, the actuating occurring at least one of at randomly selected times, at predetermined times and at predetermined time intervals;
• and
• a relay configured for communication with the distributed sensing unit and the controller;
• the relay being operable:
• (i) to trigger a first testing-event alarm condition in response to a signal received from the distributed sensing unit indicative of an occurrence of a simulated sensing event if the first change is detected;
• and
• (ii) to trigger a sensing-event alarm condition in response to a signal received from the distributed sensing unit indicative of an occurrence of a sensing event at a location along the structure being monitored if the second change is detected by the distributed sensing unit;
• the second change including a change in the at least one physical parameter associated with the at least one sensing cable,
• wherein the controller is operable to monitor a response of the distributed sensing unit to the change in the at least one physical parameter associated with the at least one test cable and to trigger a second testing-event alarm condition indicative of an occurrence of a malfunction in the distributed sensing system if no change has been detected within a predetermined time period.

A distributed sensing system comprising:

• at least one fibre optic sensing cable laid out on or along a structure to be monitored;
• a distributed sensing unit for sensing along a sensing line at least one physical parameter associated with the sensing line at a location thereof;
• the at least one physical parameter being selected from the group consisting of:
• (a) temperature;
• (b) strain;
• and (c) temperature and strain;
• the distributed sensing system being optically coupled to the at least one sensing cable;
• at least one fibre optic test cable optically coupled to the at least one sensing cable to form the sensing line;
• at least one device arranged relative to the at least one test cable to induce a change in the at least one physical parameter associated with the at least one test cable;
• the change being detectable by the distributed sensing unit;
• a controller configured for autonomously actuating the at least one change-inducing device to thereby test the efficacy and reliability of the distributed sensing unit, the actuating occurring at least one of at randomly selected times, at predetermined times and at predetermined time intervals;
• and
• a relay configured for communication with the distributed sensing unit and the controller;
• the relay being operable to trigger an alarm condition in response to a signal received from the distributed sensing unit indicative that a change in the at least one physical parameter associated with the sensing line at a location thereof has been detected,
• wherein the controller is operable to monitor a response of the distributed sensing unit to the change in the at least one physical parameter associated with the at least one test cable based on input received from the relay or the lack thereof and to measure a time elapsed between the occurrence of the change in the at least one physical parameter associated with the at least one test cable and a detection thereof by the distributed sensing unit.