Study On Gas Supply Reliability Of Natural Gas Trunk Pipe Network Based On Hydraulic Condition

As a clean, efficient, fossil energy, natural gas is an important way of the21st century world energy structure optimization, and the pipeline is the best choice of the gas mass transfer. The span of China’s natural gas resources and markets is large, there are bad geographic conditions, numerous ecological sensitive and complicated social environment along the pipeline, the user needs is also diverse. All of these factors comprehensive intertwined, makes China’s natural gas pipeline network become the world’s most complex gas transmission pipeline network system, and has the most difficult transportation task. As the key factors of manufacturing and supply of natural gas, the role of natural gas pipeline network is self-evident, the quality of the network also directly determines the manufacture and supply of gas field. Natural gas pipeline network system has a very high requirements on safety and gas transmission capacity. Therefore, system reliability should be incorporated into the whole process of network planning, design, and operation maintenance, thorough control the network system reliability and the regularity of interaction between the units of a comprehensive is the inevitable requirements of the development of natural gas pipeline in our country. In this paper, study the gas supply reliability of natural gas pipeline network system based on the analysis of the hydraulic conditions of the fault condition of pipe network system.Integrated reliability evaluation of natural gas pipe network system, the first step should be study on the topological structure of network in fault conditions, according to the topological structure of fault conditions, combine with the basic model of hydraulic calculation, calculating the flow distribution of fault conditions, according to the calculated results of the flow, finish the final calculation of reliability index.When research topological structure of failure network, the first plane is to build the correlation matrix associated pipe network and hybrid matrix contains valves information, using the matrix method to transform the plane into a valve pipe network model, based on the valve network model and its associated matrix, we can intuitively search out all connected subgraphs shutdown area, and then develop a fault element corresponding off valve program, by searching the plane pipe network fault isolation, network fault reconstruction.According to the characters of gas flow in the pipe, setting up the basic model of the gas pipe network hydraulic calculation, based on node equation method, combined with the basic knowledge of graph theory, compiling the pipe network hydraulic calculation program by using MATLAB software. On the base of the hydraulic calculation model and the fault network topology structure, pipe network system hydraulic analysis model in fault conditions is established. Using TGNET for Gas software to simulate the hydraulic calculation results of fault conditions to verify the accuracy of the calculation results.Finally, based on the state space method to establish the basic model for quality evaluation of reliability, analyze the reliability index evaluation scope, establishing the design load reliability index and the quota supply reliability index for comprehensive evaluation of system reliability. In addition, we propose to introduce the idea of stress-strength interference theory into supply reliability evaluation, the market demand is regarded as stress, gas supply capacity as strength, establishing the demand-supply interference model, and using the Monte Carlo method to solve the supply reliability.Then, through the calculation of valve net, hydraulic model of failure network, and quota supply of gas reliability index calculation, the integrated reliability evaluation of natural gas pipeline network system is completed.