For the upgrade at Middleton, wireless promised to be lower cost, offered faster installation and start-up, as well as easy integration into the existing RTUs using Modbus serial communications. Although there is minimal traffic on the road dividing the Middleton facility, Bord Gáis could not use a line-of-sight wireless solution as the signal may be interrupted by passing cars affecting the reliability of the communications.
At Middleton, Rosemount wireless transmitters included five measuring pressure, one differential pressure, and one temperature. All have been successfully installed and are sending measurements back to the control room via the RTU. The devices are placed in enclosures, standard practice for all instrumentation used at Bord Gáis AGIs, and the Smart Wireless Gateway is positioned within the instrumentation kiosk, which is effectively a “walk in” enclosure.
“We found that the enclosures do not interfere with the signals at all. We tested a few devices that were positioned furthest away from the gateway and these worked without any problems so we proceeded to install the rest of the transmitters,“ explained Brid Sheehan, Communication & Instrumentation Engineer, Bord Gáis. “Reliability of the wireless signal has not been an issue. We trend the wireless transmissions from the control room so we can see if there are any problems, but so far there hasn’t been any.“
‘EASY TO INSTALL AND INTEGRATE’
Reliability improved at PPL Generation
At PPL Generation power plants in Pennsylvania, Smart Wireless technology has proved to be “extremely cost-effective and reliable.” For example, in providing continuous performance data on critical boiler feed pumps at the Montour power stations as well as feedwater and air heaters at the Brunner Island Unit 1. “The additional information provided by the wireless instruments allows us to more effectively monitor the mechanical and thermal performance of these valuable assets,” says Joe Murach, supervisor of equipment reliability.
Key temperature and pressure measurements were not available previously to populate software designed to analyze thermal performance and determine preventive maintenance schedules. Company officials had long wanted to obtain this information, but the high cost of installing wiring was a roadblock they could not overcome. Wireless was the only option for obtaining the needed data, Murach says.
“The Emerson technology is able to handle the power plant environment,” Murach says. “The transmitters communicate with the gateway without a problem even across several floors and through walls. Going wireless eliminated the need for drilling through concrete decks, installing conduit and cable trays, and pulling wires. Instead, we have an easily installed, cost-effective and reliable wireless network.”
“We are now able to more closely monitor the condition of our valuable assets like the feedwater pumps and determine the thermal efficiency of critical equipment,” adds Murach. “The newly available information allows us to optimize boiler efficiency and detect problems at their onset. This enables our maintenance personnel to make repairs at the most opportune time rather than waiting until something fails unexpectedly.”