ASSESSMENT OF GAS PARAMETERS UNCERTAINTY IN A DAMAGED GAS PIPELINE BASED ON A STEADY-STATE GAS FLOW MODEL

Detecting gas leaks due to damage to gas pipelines and determining the volume of natural gas losses is important for reducing the imbalance in gas pipeline systems and increasing their reliability. The volume of lost gas can be determined based on the pressure and temperature of the gas at the location of the damage and the geometric characteristics of the damage. Since the gas parameters at the place of damage to the gas pipeline may differ significantly from the measured values ​​of the gas parameters at the nodal points, they should be determined based on mathematical models of gas movement. While determining the volume of lost gas, it is also essential to estimate the uncertainty of this volume, which requires also estimating the uncertainty of the pressure and temperature of the gas at the point of damage. This article is devoted to developing analytical equations for assessing the uncertainty of gas pressure and temperature at the damage point, obtained using a mathematical model of steady-state gas flow. The methodology for evaluating the uncertainty of gas pressure and temperature at the pipeline damage point is considered, taking into account various factors such as pressure, temperature, flow rate, gas composition, and the geometric characteristics of the pipeline. The research relies on standardized procedures and methods for uncertainty analysis presented in JCGM 100:2008 and ISO 5168:2013. As a result of the study, equations for the relative standard uncertainty of pressure and temperature of natural gas at the damage point were derived, and the influence coefficients of the uncertainty components were found, enabling the assessment of these parameters' uncertainty while considering the uncertainties of the pipeline's geometric characteristics and the flow gas-dynamic parameters. Examples of calculating the relative standard uncertainty of pressure and temperature of the gas at the damage point are provided for the case of a complete pipeline rupture. The obtained equations for the uncertainty of pressure and temperature of gas at the damage point will serve as the basis for the methodology for estimating the uncertainty of the volume of gas lost due to damage.