Pipe Friction Parameters Identification And The Mutiple Hydraulic Conditions Analysis Of Heat-supply Networks

In the heat-supply networks, the accuracy of pipe friction parameters (PFPs)values could affect network running level, pipe network reliability andsimulation results. In previous studies, most scholars believe that using theobserved data of multiple hydraulic conditions relative to single hydrauliccondition can get better identification results, but there is not much theoreticalresearch about using the multiply conditions to identify PFPs. When all nodespressure heads and nodes discharges observed values in a certain hydrauliccondition are available, the PFPs identification equations are consistent and haveinfinitely many solutions.And it is not able to obtain PFPs unique values. So thispaper will analyse the identification feasibility of PFPs unique values by usingthe all nodes pressure heads and nodes discharges observed values of multiplehydraulic conditions respectively from the solution existence of identificationalgebraic equations and observability theory.When the all nodes pressure heads and nodes discharges observed values areknown in the multiple hydraulic conditions, this paper establishes the heat-supply network PFPs identification mathematical model by decoupling theenergy equations which tree branch pipes and link branch pipes meetrespectively. And this paper put forwards the concept of identificationuncertainty and points out that there is a minimum condition number to identifythe PFPs unique values.The article study the PFPs unique values identificationproblem based on the observability theory. It is found that when the hydraulicconditions are similar, it is not able to obtain the PFPs unique values by usingmultiple hydraulic conditions.In the actual heat-supply network, the node pressure observed data generally arepartially available. So the paper studies the PFPs unique values identificationrelated problem in the multiple hydraulic conditions when the node pressureobserved data are partially available. Finally a numerical example is carried outin the different observation conditions, which illustrates that PFPs unique valuescan be obtained by using the observation data of multiple hydraulic conditionsand it improves the accuracy of identification results effectively. The study purpose of this work is in order to establish a theoretical calculation frameworkfor solving PFPs unique values in the multiple hydraulic conditions and providethe theory basis for the PFPs identification problem of actual heat-supplynetwork in the multiple hydraulic conditions.