Smart Sensor Technology for Gas Pipeline Monitoring Hawk Measurement Systems

Fibre Optic Distributed Sensor (FOS) The optical fibre cable is the sensor: The multiple core Fibre To The Home (FTTH) cable can be used as a distributed acoustic and strain sensor. The standard loose tube telecommunication fibre cable could be used as a temperature sensor.

FOS The optical fibre cable is the sensor: Sheath Loose tube Optical fibre Adhesive tape Ideal design integrates loose tube fibre (for temperature sensing), tight buffered fibre (for strain and acoustic sensing) and adhesive tape together in one cable, so it could stick to flat surface.

Distributed Acoustic Sensor (DAS) Leak sound signal location Leak sound waveform The TRS called for New Installations, however, it has always been clear, although unstated, that there also needs to be a solution for existing infrastructure. Intensity (a.u.) Intensity (a.u.) Time (ms) Position (m) Detect leak position Detect leak hole size

DAS Third party interference detection: Position (m) Time (ms) The TRS called for New Installations, however, it has always been clear, although unstated, that there also needs to be a solution for existing infrastructure. Position (m) Intensity (a.u.) Sound signal location Time (ms) Intensity (a.u.) Sound waveform

Performance Specifications for DAS Maximum fibre length 50 km Spatial Resolution 0.5 m Location accuracy Within 5 m or better Identify activities Gas leak, Gas pressure and leak hole size, digging, normal vehicle, human and animal passing etc. Acoustic wave bandwidth 0 – 20 kHz distance pending Real time detection Yes Two channel detection to minimize signal fading Tolerance to single cable fault* Fault Detection / Reporting Programmable fault alarms and reports Sensor Life Time >30 years Operating temperature range Control unit: +5 OC to +60 OC Optical fibre cable: -30 OC to +70 OC Control unit size 4U 19” rack enclosure Operating Voltage 90 – 250 Vac 9-30 Vdc Power consumption <180 VA The TRS called for New Installations, however, it has always been clear, although unstated, that there also needs to be a solution for existing infrastructure. * Both fibre ends need to be accessible (DAS2)

Temperature Detection (Joule-Thomson effect) Leakage from a compressed gas line is identified by the development of a cold spot due to the pressure release known as the Joule-Thomson effect. Typical Joule- Thomson effect figures for natural gas are -0.5°C/ bar x delta p which indicates that small pressure changes result in significant temperature variations. The pipeline outer surface being rapidly cooled by the Joule-Thomson effect, a temperature gradient develops in the soil around the pipeline surface. The speed of the temperature gradient development depends on the type of soil and may vary from a few seconds to a few minutes. The cooling effect is independent of the soil temperature and that the magnitude of the cooling effect remains the same regardless of soil temperature. The TRS called for New Installations, however, it has always been clear, although unstated, that there also needs to be a solution for existing infrastructure.

Distributed Temperature Sensor (DTS) Fibre optic sensor detection of temperature change over a 12m region: The TRS called for New Installations, however, it has always been clear, although unstated, that there also needs to be a solution for existing infrastructure.

Performance Specifications for DTS Maximum fibre length 50 km Spatial Resolution 0.5 m Location accuracy Within 5 m or better Temperature Resolution 0.1 C Temperature Accuracy ±0.1C Signal Averaging 1 to 16,000,000 Data collection time 1 to 30 seconds, dependent on distance, accuracy and interrogation method. Fault Detection / Reporting Programmable fault alarms and reports Sensor Life Time >30 years Operating temperature range Control unit: +5 OC to +60 OC Optical fibre cable: -30 OC to +70 OC Control unit size 4U 19” rack enclosure Operating Voltage 90 – 250 Vac 9-30 Vdc Power consumption <180 VA

Distributed Strain Sensor (DSS) Distance (m) The strain change at a pipe surface and deformation of a pipe could be detected by optical fibre cable. Multiple cables can provide strain detail along more than one axis.

Performance Specifications for DSS Maximum fibre length 50 km Spatial Resolution 0.5 m Location accuracy Within 5 m or better Strain Resolution 2με Strain Accuracy ± 2 με Signal Averaging 1 to 16,000,000 Data collection time 1 to 30 seconds, dependent on distance, accuracy and interrogation method. Fault Detection / Reporting Programmable fault alarms and reports Sensor Life Time >30 years Operating temperature range Control unit: +5 OC to +60 OC Optical fibre cable: -30 OC to +70 OC Control unit size 4U 19” rack enclosure Operating Voltage 90 – 250 Vac 9-30 Vdc Power consumption <180 VA

Multiple Parameter FOS Combination of sound, temperature and strain detection minimizes the chance of false alarm DAS-Sound DTS-Temperature DSS-Strain Fiber optic sensing can detect and localise leaks continuously and accurately along the entire length of the pipeline. It detects the signature of leak: Leak sound, cool spot due to leak and strain change.

Fibre Optic Sensing Distributed sensor can continuously monitor vibration, strain and temperature on pipe line for the entire length of optical fibre. Fibre optic cable is easy to install. Fibre optic cable is passive – No electrical power required. Little or no maintenance required. Fibre optic sensing has low cost. Fiber optic sensor is weather independent without being compromised by rain, fog etc, and not disturbed by moisture, dust or smog.

Scope of Monitoring Vibration and sound of leak and third party intrusion Temperature Stress, strain along tensile members and cables attached to pipeline Emergence of pipe deformation Loss of ground support due to soil erosion

HAWK Fibre Optic Sensor (HAWK FOS) HAWK fibre optic sensing data collection system compares outputs from multiple technologies to improve sensing reliability and discriminate against false positives. Advanced cable design improves sensitivity of both temperature and strain measurement. Enhanced acoustic sensing technology virtually eliminates signal fading. Simple filtering and performance enhancement software.

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