Identification of model flow parameters and model coefficients with the help of integrated measurements of pipeline system operation parameters

The problem of state and parameter estimation of natural gas pipeline system under stationary and non-stationary gas flow is considered. The initial information for solving the problem are pressure and flow measurements with standard measuring equipment. Measurement errors are considered random values that have a normal distribution with zero expectation. The developed methodology takes into account the whole complex of measured parameters in their relationship. The problem reduces to an optimization task; the objective function is derived from the maximum likelihood method. The effectiveness of the methodology was tested on a real object – a complex gas distribution system of a looped structure. The hydraulic efficiency coefficients for this facility are estimated in stationary and non-stationary modes. We use a non-standard model with lumped parameters, which allows us to switch from a system of partial differential equations to a system of ordinary differential equations connecting nodal pressures and flow rates at the arcs of the network graph. In a computational experiment using the gas pipeline branch as an example, the developed algorithm showed very fast convergence.