Gas transmission system software integrity

Considers two gas transmission stations at either end of the pipeline sited in areas of different population density, this would mean that different pressure constraints would be placed upon them. The solution currently used in the gas industry is to control the outlet pressure of the up stream station, to a value which could exceed 100 lbf/in/sup 2/. The up stream pressure is modulated by a programmable process controller. The control system and its software maximises the pressure inside the population boundary, but also ensures that the pressure inside the boundary does not exceed 100 lbf/in/sup 2/, even at times of low demand when a small pipeline pressure drop occurs. In the software of the process controller is a pipeline model which will calculate the measured variable i.e. the down stream station pressure. The system software is used to improve the accuracy and integrity of the actual and calculated measured variable.<
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