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 • The standard loose tube telecommunication fibre cable could be (FTTH) cable can be used as a used as a temperature sensor. distributed acoustic and strain sensor. FOS The optical fibre cable is the sensor: Sheath Optical fibre Adhesive tape • Loose tube 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 Intensity (a.u.) Intensity (a.u.) Leak sound waveform Position (m) Detect leak position Time (ms) Detect leak hole size DAS Third party interference detection: Sound waveform Intensity (a.u.) Intensity (a.u.) Sound signal location Position (m) Time (ms) 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 Yes Tolerance to single cable fault* Yes Fault Detection / Reporting Programmable fault alarms and reports Sensor Life Time >30 years Operating temperature range Control unit size Operating Voltage Power consumption * Both fibre ends need to be accessible (DAS2) Control unit: +5 OC to +60 OC Optical fibre cable: -30 OC to +70 OC 4U 19” rack enclosure 90 – 250 Vac 9-30 Vdc <180 VA 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 JouleThomson 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. Distributed Temperature Sensor (DTS) Fibre optic sensor detection of temperature change over a 12m region: 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 ±0.1C 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 Control unit: +5 OC to +60 OC Operating temperature range Control unit size Optical fibre cable: -30 OC to +70 OC 4U 19” rack enclosure 90 – 250 Vac Operating Voltage Power consumption 9-30 Vdc <180 VA Distributed Strain Sensor (DSS) Strain () 130 80 30 -20 7570 7575 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. 7580 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 size Operating Voltage Power consumption Control unit: +5 OC to +60 OC Optical fibre cable: -30 OC to +70 OC 4U 19” rack enclosure 90 – 250 Vac 9-30 Vdc <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. Thank You!