Method and system for controlling fluid transportation in a pipe network

A control system for fluid transportation comprising:

• means for reserving fluid;
• a plurality of demand nodes for exhausting the fluid;
• a pipe network for connecting said reserving means with said demand nodes;
• a plurality of sensors located at a predetermined number of points in said pipe network which number is less than the number of said demand nodes for detecting flow parameters in said pipe network at said points;
• adjust means located at a selected point in said pipe network for adjusting the flow rate of said fluid in said pipe network;
• a memory unit for storing past demand volumes of said fluid at said demand nodes;
• demand volume prediction means for predicting at first time intervals demand volumes of said fluid at said demand nodes from said past demand volumes read from said memory unit;
• operation plan scheduling means, in response to said predicted demand volumes supplied from said demand volume prediction means, for calculating operation plan scheduling values for flow rates and pressures in said pipe network and a manipulation amount of said adjust means based on said predicted demand volumes;
• demand volume estimation means connected to said demand volume predicting means, operation plan scheduling means and said plurality of sensors to respectively receive said predicted demand volumes, said operation plan scheduling values and said detected flow parameters, said demand volume estimation means estimating at second time intervals shorter than said first time intervals, in response to a manipulation amount supplied thereto, a demand volume of said fluid for each of said demand nodes as a function of a linear pipe network equation based on said manipulation amount, said detected flow parameters, said predicted demand volumes and said operation plan scheduling values, said estimation means storing said estimated demand volume in said memory unit and further estimating a demand volume of said fluid for each of said demand nodes to be used in the next control cycle of said adjust means based on said first mentioned estimated demand volume;
• and
• manipulation amount calculation means connected to said demand volume predicting means, said operation plan scheduling means and said estimation means for calculating, in response to said further estimated demand volume supplied from said estimation means, a manipulation amount of said adjust means based on said predicted demand volumes, said operation plan scheduling values and said further estimated demand volume and for controlling said adjust means in accordance with said calculated manipulation amount such that variations in flow rates and pressures caused by variations in said estimated demand volumes approach said operation plan scheduling values by calculating said manipulation amount to meet a predetermined evaluation function.

A method for controlling fluid transportation in a pipe network system having means for reserving fluid, a plurality of demand nodes for exhausting said fluid, a pipe network for connecting said means with said demand nodes, a plurality of sensors located at a predetermined number of points in said pipe network which number is less than the number of said demand nodes for detecting flow parameters in said pipe network at said points, adjust means located at a selected point in said pipe network for adjusting a flow rate of said fluid in said pipe network, and a memory unit for storing a pattern of past demand volumes of said fluid at said demand nodes, the method comprising:

• a first step of reading out said pattern of past demand volumes from said memory unit and calculating predicted demand volumes y.sub.r of said fluid at said demand nodes;
• a second step of calculating operation plan scheduling values for flow rates, pressures and a manipulation amount from said predicted demand volumes y.sub.r calculated in said first step and from corresponding scheduled values by pipe network analysis,
• a third step of estimating flow parameters in said pipe network based on said predicted demand volumes y.sub.r calculated in said first step and said operation plan scheduling values calculated in said second step, from the flow parameters detected by said plurality of sensors and a change of said manipulation amount and flow balance requirements and pressure balance requirements in said pipe network to estimate a demand volume of said fluid for each of said demand nodes and storing said demand volume in said memory unit and to further estimate the variation of said demand volume;
• a fourth step of calculating manipulation amounts u.sub.r based on said predicted demand volumes y.sub.r calculated in said first step and said operation plan scheduling values calculated in said second step and said estimated demand volume estimated in said third step, and controlling said adjust means in accordance with said amounts u.sub.r which causes differences between said flow parameters estimated in said third step and scheduled values to be smaller than predetermined values.

A method for controlling fluid transportation in a pipe network system having means for reserving fluid, a plurality of demand nodes for exhausting said fluid, a pipe network for connecting said means with said demand nodes, a plurality of sensors located at a predetermined number of points in said pipe network which number is less than the number of said demand nodes for detecting flow parameters in said pipe network at said points, adjust means located at a selected point in said pipe network for adjusting the flow rate of said fluid in said pipe network, and a memory unit for storing a pattern of past demand volumes of said fluid at said demand nodes, the method comprising:

• a first step of reading out said pattern of past demand volumes from said memory unit and calculating predicted demand volumes y.sub.r of said fluid at said demand nodes;
• a second step of calculating operation plan scheduling values for flow rates and pressures in said pipe network and a manipulation amount of said adjust means from said predicted demand volumes y.sub.r calculated in said first step so that said calculated scheduling values satisfy a desired optimum operation plan,
• a third step of estimating flow rates x and pressures p in said pipe network based on said predicted demand volumes y.sub.r calculated in said first step and said operation plan scheduling values calculated in said second step from the flow rates and pressures detected by said plurality of sensors and a change in manipulation amount .DELTA.u.sub.t and flow balance requirements and pressure balance requirements in said pipe network to estimate a demand volume y.sub.t of said fluid for each of said demand nodes and storing said estimated demand volume in said memory unit, and further estimating a demand volume y.sub.t+1 for the next control cycle of said adjust means based on said first mentioned estimated demand volume y.sub.t and a preselected statistical variation parameter,
• a fourth step of calculating a manipulation amount u.sub.t+1 based on said predicted demand volumes y.sub.r calculated in said first step and said operation plan scheduling values calculated in said second step and said further estimated demand volume estimated in said third step, and controlling said adjust means in accordance with said calculated manipulation amount u.sub.t+1 so that variations in the flow rates and pressures caused by variation in the estimated demand volumes approach said operation plan sheduling values.