Calibration Equipment at Seabank Power Station.

Seabank Power is a recently commissioned CCGT
(Combined Cycle Gas Turbine) electricity generating plant
situated in Hallen near Bristol within site of the new impressive
Severn Bridge.

 The station was built as a 'turn-key' contract by
 Siemens Power Generation and runs 24 hours a day,
 365 days a year barring routine maintenance outages.
 Seabank Power consists of two generating modules
 the second of which is in final commissioning and is
 due for hand-over by the end of the year.
 The first module has two single shaft gas turbines
 with HRSG (heat recovery steam generators) on the
exhaust end supplying steam to the single steam turbine.

The arrangement is highly efficient as the waste gasses from the
combustion process are used to heat water to create steam for the
stream turbine. This arrangement produces approximatley 75 5MW 
epending on ambient conditions. The station will become a 1200WM
site when the second modules' generation is included.

The Gas Turbines uses odourless natural gas, which is transferred
to the Main site at Hallen from the Gas Compression site at Pucklechurch
through a purpose built 27km pipeline. This provides approximately
8 hours of running on stored gas in the pipe.

Seabank Powers water cooling system uses secondary treated sewage
water which is further treated on site to a very high standard and recycled
in the system which improves efficiency and increases water purity as the
water changes state.

Due to the complexity of the process the control system is very measurement
intensive meaning that Seabank Power's Maintenance Department has a full
time job providing calibration, repair and routine servicing of these devices
around site.

Plant Measurement Equipment
Most measurements are performed by sensors and transmitters situated
around the plant. In total, there are over 4000 of these devices in use,
60% of which are monitoring pressure, 30% temperature and the remaining
10% measuring other parameters such as vibration, pH, flow etc.

 The pressure transmitters, most of which are 4-2OmA devices
 from a mixture of suppliers, monitor pressure of water, steam,
 gases (natural gas, hydrogen, carbon dioxide) and oil
 (for lubrication and cooling). Pressure ranges vary from vacuum
 through to 250bar, in gauge, absolute or differential modes.
Maintenance Department The maintenance department was designed to handle these activities, which needed to be furnished with suitable equipment to perform calibration, management and repair servicing. In the process of selecting the equipment for the department several suppliers were considered including Beamex, Druck, Fluke and Haven Automation. The chosen supplier would need to have the capability of supplying portable calibration instruments for on-site work, a comprehensive test bench for the department and calibration management software to control effectively and simply the large number of sensors and transmitters. It was important for the equipment in all these tasks to be up to date and supported by an experienced engineering supplier team. After careful study and negotiation with several suppliers, it was decided that Beamex could fulfil all the requirements in offering a complete package with their new MC5 portable calibrator, the comprehensive and flexible facilities of their test benches, and the QM6 calibration management software.
The chosen Beamex equipment is now in regular use, with the MC5 portable calibrator proving ideal for use around the plant performing calibration and operational checks for transmitters in-situ, saving considerable time in avoiding removal of the unit and returning to the workshop for investigation. Dave Avent of Seabank Power commented... "Beamex visited our site with their demonstration trailer, where we were able to see and discuss their wide range of calibration equipment and software". Dave continued... "We were one of the first to purchase the new MC5 calibrator and it has more than proved itself in its portable role.
At present we use the standard model with 2 bar and 20 bar internal sensors, together with the optional external module giving us pressure calibrations up to 160 bar. We simply download calibration management information for particular transmitters from the QM6 software on the test bench computer and perform all the checks we need at the transmitter point on the plant. We hope to increase our number of MC5's in the near future. The test bench performs many functions and is fitted with a choice of supplies and calibration procedure equipment, including a PC loaded with the QM6 software package. This contains a database of all the transmitters in use containing a history of calibration information together with dating details to initiate when calibration checks are needed to be performed. This software is an invaluable tool in the calibration process, particularly with logging characteristics of the large number of transmitters present on the station. With all of these Beamex facilities, the maintenance engineers can undertake many activities including calibration, general service and some repair work such as resetting of zero and span controls, through to a complete instrument calibration. Dave agrees that their present set-up is more than fulfilling the tasks that they present to it and foresees extension in the future to include more MC5 portable calibrators and making use of their second license on the QM6 calibration software by bringing in a second PC system. Successful Combination A successful combination of Beamex's comprehensive calibration systems being used by Seabank Power Station, an up to date electricity generating plant employing the latest methods in efficiency, technology and environmental friendly procedures. ___________________________________________ For more information, please contact:- Beamex Ltd. Tel: +44(0) 1455 821920 November 2000

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