| Real-time calculation of node flow and online simulation for city gas network has been systemically studied in this paper, and the study result has been confirmed in case of medium pressure gas network of Baoji city, the realization of online simulation is important to achieve optimal scheduling and intelligent operation for the city gas network. The main contents of this paper are as follows.(1)The node flow and the friction coefficient and other factors that affect the simulation accuracy of gas network are discussed, combining with user types of gas supply and various users of the gas law and at the base of getting business data and meter reading data, the coefficient of variation of node flow is gotten. According to the coefficient of variation of node flow, real-time online calculation for node flow of monitored users and general users is realized.(2)The Chung method, Lucas method. Residual viscosity method and Unified corresponding state method of four calculations for gas kinematic viscosity has been compared and analyzed, gas kinematic viscosity has been calculated using unified corresponding state method with high accuracy, friction factor of gas network is analyzed and calculated using Newton iteration method, compared with the traditional test method, the Newton iteration method has high accuracy.(3)Taking into account the characteristics of large storage capacity and access speed of online simulation data, database system of off-line simulation software was improved and ODBC data access interface based on access database of off-line simulation software was conversed to ADO data access interface based on SQL server2000 database was completed and the foundation was laid for to realize the online simulation of simulation software. Through the real-time data access interface,the monitoring data of SCADA system was gotten directly to realize the function of non-uniform time intervals of online simulation, analysis and calculation of off-line simulation and online load forecasting of nodes and the online simulation has high accuracy through the engineering example.(4)Based on the original function of steady-state gas pipeline network simulation software, tool tip in window client area for nodes and pipe information of network model and object query functions for finding the node number and pipe number were added, which improve the engineering practicality of simulation software and lay the foundation for online simulation. SCADA system measured data and online simulation data of Baoji city the medium pressure gas network were comparative contrasted and analyzed, simulation errors are within±5%, it can meet the needs of production operations and scheduling management and realize intelligent operation and optimize scheduling of city gas network. |
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