Objective Pipeline network managers need to calculate the transmission loss daily. When the transmission loss exceeds the warning value, it is necessary to analyze the abnormal causes. An accurate calculation method of the transmission loss is conducive to the early detection of problems and provides support for the analysis of causes.

Method By selecting a certain step size, the pipeline between adjacent stations of the long-distance natural gas pipeline was divided into several control volumes. Using the classic fourth-order R-K formula, the temperatures and pressures at both ends of different control volumes were calculated respectively. When the step size was small enough and the temperature and pressure changes at both ends of the control volume were extremely small, the average pressure and temperature of the control volume could be taken to calculate the pipeline stock of the control volume, and then the transmission loss could be calculated.

Result In the case of accurate measurement of the metering instrument and the adoption of the AGA 92DC method for the calculation of the compression factor, the absolute value of the transmission loss rate calculated by this method was mostly smaller than that of the field method, and the average value of the absolute value of the transmission loss rate calculated by this method was smaller than that calculated by the field method.

Conclusion The transmission loss rate calculated by this method is smaller than that calculated by the field method, and the transmission loss calculated by the field method is larger.