New Technology Leading the Way for Pipeline Leak Detection
The United States has the largest network of energy pipelines in the world, with more than 2.4 million miles of pipe. Pipelines are used to transport and distribute fluids such as oil, natural gas, water, and petroleum-based products over long distances. Typically, pipelines are located underground and have been deemed difficult to monitor and inspect. It is vital to keep pipelines operating smoothly and to quickly detect any sign of leakage or other physical damage.
Hawk Measurement (HAWK) has designed and developed a revolutionary technology that immediately detects pipeline leakage, ground disturbances, manual and machine excavation, theft, hot tapping and vehicle movement on buried and unburied pipelines. Not only does it detect and alert, but it also provides an accurate location of the occurrence, allowing for extremely rapid response and quick repair. HAWK’s Praetorian System features Fiber Optic Sensing (FOS) technology, allowing for continuous real-time monitoring of long assets such as pipelines. The Fiber Optic Cable is installed along the pipeline and senses changes in sound, stress, temperature or vibration, allowing the system to cross-reference and remove false signals. Unlike other Fiber Optic Sensing companies on the market that only look at temperature, HAWK’s Praetorian System features temperature and vibration (multi-variable sensing) to positively identify the leak.
There are two main ways that leakages are detected through distributed sensors. The two methods are called Distributed Temperature Sensing (DTS) and Distributed Acoustic Sensing (DAS) and they respond to changes in temperature and vibration respectively. Distributed Acoustic Sensor (DAS) systems look for the noise generated by the fluid escaping (under pressure), which then vibrates the pipe wall that the fiber is connected to. This vibration has been able to detect leaks down to half a liter (0.13 Gallons) per minute in water pipelines.
Distributed Temperature Sensor (DTS) systems rely on a physical principle called the Thompson-Joule effect, which is attributed to a localized drop in temperature that occurs when any fluid is moved from high to low pressure. An example of this is aerosol cans getting cold with extended use or a barbeque gas cylinder freezing on a hot day. This effect is more prevalent in gases but does occur in liquids and slurries. This localized drop can be detected and subsequently the presence of a leak can be inferred. Temperature only systems are not recommended for leak detection applications.
The best choice is a Multi-variable Fiber Optic Sensing System. The main advantage of these sensors is the resistance to false reporting. Typically, these Multi-variable Fiber Optic Sensing Systems are configured in such a way that means that both an appropriate DAS and DTS response should be seen at the same location for a signal to be confirmed to be a leak, an increase in acoustic signal must be present at the same place as a localized decrease in temperature. This built in “self-checking” method means that not only is the system highly accurate but also immune to almost all environmental effects (such as rain, snow, wind, etc.) and is all but tamper proof. Due to the optical nature of the signal captured by the device, the systems are immune to all electrical and environmental interference, unless the fiber optic cable is crushed or has severed the system. For this reason, HAWK’s Praetorian has been designed with multi-variable sensing, to detect changes in liquid or gas temperature movement, sound and vibration from third-party intrusions and changes in stress or strain due to pipe bending or loss of support in order to detect pipeline leaks.
The Praetorian Fiber Optic Sensing System uses a combination of Rayleigh backscatter and time of flight technology to determine the presence, location, intensity and frequency of vibrations along an optical fiber in real time. The Fiber Optic Sensing System has a built-in Human Machine Interface (HMI) and can be operated directly or connected to an existing Control System such as a SCADA. The Fiber Optic System can provide alarm notifications (red, amber, and green) depending on the condition of the components. Reporting and alarms can be sent to smart phones, tablets and computers via SMS and email alerts. The report includes the location of an alarm, the alarm classification, its longitude and latitude, the alarm intensity as well as the time and date. Installation is easy and there is no maintenance or calibration required after commissioning. The Praetorian Fiber Optic System is very intuitive and is built with self-diagnostics to self-monitor the unit’s condition and maintain optimum performance. HAWK’s Praetorian is alsod equipped with a predictive analysis feature to determine occurrences such as excavation, leaks or pipeline corrosion before they even happen. This type of preventative technology saves thousands.
When it comes to monitoring something as critical as pipelines, a reliable and accurate leak detection system is imperative. Unlike other fiber optic sensing systems on the market, HAWK’s modular hardware and software are unique and has world leading specifications, minimizing false positives and maximizing flexibility, leading HAWK to have the best sensing capability on the market. Incorporating smart technologies to detect, predict and prevent potential catastrophes is essential for corporations and industries worldwide.