36 COMMUNICATIONS/TELEMETRY
Gas pipeline monitoring: moving from analogue to wireless
As it continues with a major expansion of its natural gas pipeline transmission system, a major Irish energy provider has invested in wireless technology. This, as Sean Ottewell reports, both replaces ageing, hardwired devices and acts as part of a trial to decide the future specifications that the company requires.
Como parte de la
importante ampliación de su sistema de transmisión de tuberías de gas, uno de los principales proveedor de energía irlandeses ha invertido en tecnología inalámbrica. Sean Ottewell explica que dicha inversión tiene como objetivo sustituir los dispositivos cableados antiguos y a la vez forma parte de un ensayo para decidir las especificaciones de futuro que requiere la empresa.
Mit dem enormen Ausbau der eigenen Erdgas- Pipeline hat ein namhafter irischer Energieversorger in die Wireless- Technologie investiert. Im Zuge dessen, so bereichtet Sean Ottewell, werden nicht nur veraltete und fest verschaltete Anlagen ersetzt, sondern es ist auch Teil eines Versuchs, der über die zukünftigen Spezifikationen entscheidet, die auf der Wunschliste des Unternehmens stehen.
transmission and distribution of natural gas to more than 600 000 customers.
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Management of the gas pipeline system is a sophisticated 24-hour operation involving constant monitoring through supervisory control and data acquisition (SCADA) systems. Gas is transmitted at high pressure, around 60–80 bar, from its main facilities and then at remotely located above ground installations (AGIs) it is reduced appropriately to supply regional distribution points and commercial customers. Bord Gáis has in excess of 200 AGIs throughout Ireland, and at all these sites the gas lines in and out are monitored. Existing AGIs have between three and 12
pressure transmitters measuring both inlet and outlet pressure. The cooling effect as a result of pressure reduction is also measured using temperature transmitters. These devices are connected, by hardwiring, to an onsite remote terminal unit (RTU) that transmits data back to a SCADA system master terminal unit at the central monitoring station in Cork on the country’s south coast. Should thresholds be exceeded to pressure or temperature, alarms are activated. Bord Gáis’ Mains Renewal
Programme aims to ensure that the Irish natural gas facility is one of the most modern pipeline systems in Europe. As part of the process, existing AGIs reaching the end of their lifespan are being upgraded with the latest instrumentation. One such site was at Middleton, near Cork, where a number of instruments needed to be upgraded with the latest temperature and pressure transmitters. When Bord Gáis looked to upgrade the facility with new instrumentation, it was decided to use a network of wireless pressure and temperature transmitters.
The Middleton site is quite
eading Irish energy provider Bord Gáis is wholly owned by the government of Ireland and responsible for the supply,
unusual as it is divided by a road. Although cable ducting was already in place and this could have been reused, this facility presented an excellent application to test wireless technology with a view to installing wireless at other AGIs.
“Having adopted general packet radio
service (GPRS) as a back- up communications technology for our RTUs, we were very comfortable with wireless,” said Frank Smiddy, communication and instrumentation engineer, Bord Gáis. “We like to think that we are very forward thinking and open to new ideas and we are always looking to improve our service using the latest technology.” Whenever new AGIs are installed to support extensions to the pipeline system, or existing sites are upgraded, Bord Gáis is continually looking to minimise any installation costs. Power and data cabling are usually installed in ducting at the AGIs. However, burying cables can prove to be costly and time consuming. For the upgrade at Middleton, wireless promised to be lower cost, offered faster installation and start up, and easy integration into the existing RTUs using Modbus serial communications. Although there is minimal traffic on the road dividing the Middleton facility, Bord Gáis
Fig. 1. Bord Gáis’ AIG at Middleton near Cork. Ireland. In the event of obstructions such as temporary scaffolding, new equipment or a parked construction trailer, the self-organising wireless technology simply re-routes messages along the network. Courtesy of Emerson Process Management.
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