REALTIME MONITORING OF PIPELINES FOR THIRD-PARTY CONTACT
Third-party contact with pipelines (typically caused by contact with a digging or drilling device) can result in mechanical damage to the pipe, in addition to coating damage that can initiate corrosion. Because this type of damage often goes unreported and can lead to eventual catastrophic failure of the pipe, a reliable, cost-effective method is needed for monitoring the pipeline and reporting third-party contact events. The impressed alternating cycle current (IACC) pipeline monitoring method developed by Southwest Research Institute (SwRI) consists of impressing electrical signals on the pipe by generating a time-varying voltage between the pipe and the soil. The signal voltage between the pipe and ground is monitored continuously at receiving stations located some distance away. Third-party contact to the pipe that breaks through the coating (thus resulting in a signal path to ground) changes the signal received at the receiving stations. The IACC method was shown to be a viable method that can be used to continuously monitor pipelines for third-party contact. Electrical connections to the pipeline can be made through existing cathodic protection (CP) test points without the need to dig up the pipe. The instrumentation is relatively simple, consisting of (1) a transmitting station with a frequency-stable oscillator and amplifier and (2) a receiving station with a filter, lock-in amplifier, frequency-stable oscillator, and remote reporting device (e.g. cell phone system). Maximum distances between the transmitting and receiving stations are approximately 1.61 km (1 mile), although the length of pipeline monitored can be twice this using a single transmitter and one receiver on each side (since the signal travels in both directions). Certain conditions such as poor pipeline coatings or strong induced 60-Hz signals on the pipeline can degrade IACC performance, so localized testing should be performed to determine the suitability for an IACC installation at a given location. The method can be used with pipelines having active CP systems in place without causing interference with operation of the CP system. The most appropriate use of IACC is monitoring of localized high-consequence areas where there is a significant risk of third-party contact (e.g. construction activity). The method also lends itself to temporary, low-cost installation where there is a short-term need for monitoring.
- Research Organization:
- Southwest Research Institute, San Antonio, TX (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FC26-03NT41878
- OSTI ID:
- 891937
- Country of Publication:
- United States
- Language:
- English
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REALTIME MONITORING OF PIPELINES FOR THIRD-PARTY CONTACT
REALTIME MONITORING OF PIPELINES FOR THIRD-PARTY CONTACT