BP is a British oil and energy company with global headquarters in London and is one of the largest private energy corporations in the world. In the United States, BP operates numerous refineries, including one in Ohio.
Challenge
At the Ohio refinery, engineers and technicians researched wireless communication possibilities for increased efficiency and timer monitoring. They needed to determine whether reliable data transmission via radio would stand up to an environment with a high level of EMI, and if the cost of cabling a large area with remote storage tanks could be reduced or eliminated.
The power stations close to the plant carry large amounts of power via high-voltage lines, creating strong interference fields. The possible negative effects of these to wireless transmissions were the primary concern. Another problem was the lack of power at the potential installation sites of the crude tanks to be monitored. Battery power would be required at the remote sites.
For a proof of concept, the BP engineers selected a remote groundwater pump, monitoring level using an ultrasonic meter. The water level was indicated via an industry standard 4-20 mA analogue signal and when a high level limit was reached, a digital alarm signal was generated via a remote contact. Due to the remote location of this pumping station, cabling for the level and alarm information would have been cost prohibitive and impractical.
Solution
BP installed the Trusted Wireless Data Radio with I/O system from Phoenix Contact to collect the analogue and digital I/O data from the remote site, and transmit that data wirelessly back to the control station. The wiring at the remote site was straightforward using Phoenix Contact’s I/O extension modules. These add-on I/O ‘slices’ allow I/O wiring to take place as it would in a hard-wire system, but the I/O transmits without wires, making this modular approach flexible to accommodate future system expansions.
At the control room, the data from the remote site is received by another Phoenix Contact Trusted Wireless data radio where it is interfaced to the plant’s Honeywell DCS system via RS-232 cable and Modbus protocol. This allows the DCS to read and write data from/to the remote site in the same way as a conventionally wired system.
Another advantage of the solution is the option to evaluate additional information from the wireless system. In addition to the groundwater level and alarm status, the DCS can also poll RSSI (receive signal strength indication), supply voltage generated by the solar power system, and the local temperature inside the RTU. This is done via Modbus registers inside the Trusted Wireless Data Radio. These can be archived in the DCS using trend diagrams.
Summary and results
BP validates Phoenix Contact Trusted Wireless technology for reliable data transmission in high EMI environments.
Data radios with I/O provide an easy to install wireless system for access to a remote I/O site without additional remote PLCs.
Additional diagnostic values, such as RSSI, power supply voltage and site temperature are provided at no additional cost. Return on Investment estimated at over $75 000.
BP determined that if the system were cabled then it would require ditches and cables installation over a distance of approximately 1 km. The cost of completing this depends on the type of surface to be excavated for cable installation. BP estimated that by going wireless, they could save over $75 000 in installation costs.
According to BP, the wireless communication system is exceptionally reliable in the high EMI environment. As a result, BP implemented wireless technology for the level monitoring function for all the crude oil tanks on this site and at an additional plant on the Ohio River. Wireless technology is installed in a total of sixteen crude oil tanks at the plant. In addition to the Ohio site, BP has since taken several previously cabled sites, each with up to fifty tanks, and implemented a wireless monitoring solution from Phoenix Contact.
For more information contact Anike Visser, Phoenix Contact, +27 (0)11 801 8200, [email protected], www.phoenixcontact.co.za
| Tel: | +27 11 801 8200 |
| Email: | [email protected] |
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