Integrating Leak Detection Into SCADA Systems
For pipeline operators, deciding to implement leak detection is easy. However, determining how to accomplish it is hard. Leak detection is a good tool for quickly raising alarms for theft, identifying product loss due to wear and corrosion to the pipe, and/or preventing environmental events caused by spills.
Whether driven by safety and production concerns or regulatory requirements, the method chosen for leak detection has a significant impact on its effectiveness.
Approaches to leak detection can be categorized as either “external” or “internal” methods. Integrating leak detection into existing SCADA systems can provide alarm management of a leak event as well as record keeping and trending before and after the event. Locating the leak with a precise location facilitates quicker response and repairs. Choosing the approach method defines costs for new and existing systems and the practicality of adding leak detection to existing systems.
External Leak Detection Equipment
External leak detection involves the installation of detection equipment on the pipeline. Detection equipment can monitor the dynamics of the flow for changes that would indicate a leak. This type of approach uses instrumentation installed on the pipe to detect changes in sonic patterns or vibration. The ability to pinpoint the location of the leak is a function of the location of the instrumentation. Typically, the leak can be located to a section or area between instruments. Visual monitoring can employ CCTV with analytic software to monitor changes in the images captured. Installing instrumentation on new systems is costly due to the number of devices required and the communication network required. The costs go up significantly when adding leak detection to existing systems. External methods of leak detection may fail to meet expectations for several reasons:
• The installation process is quite intrusive, because it requires digging up buried pipe.
• Monitoring is very rudimentary and is a function of the pipeline SCADA operation. Operators observe an event and react to it. The speed of response is a function of how accurate the identification of the leak’s location is, and when it alarms. Some detection approaches require more significant leaks to trigger an alarm.
• The equipment is only effective if the device is in the exact right location. For example, if using vibration or sonic detection, the instrumentation must be installed frequently enough that the area of the leak can be pinpointed, and even then, you can only identify an area of concern. Where the pipe is above ground, CCTV coverage is limited even with analytic software.
• Adding a significant number of detection instruments to a system increases the operational complexity and the number of maintenance items. Considering the cost of constant monitoring, equipment repairs and the complexity of installation, external leak detection carries both a high capital expense and ongoing cost. The additional operational expense required to support this system of instruments and communication networks can be significant.
• Providing power sources to drive remotely installed monitoring equipment and instrumentation poses a host of challenges and costs.
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