Hydraulic Analysis And Optimal Operation Of City Gas Pipeline Network In Case Of Emergency

With the rapid development of the natural gas industry, the city gas was also in rapid development period, the scale of the construction of natural gas pipeline network in China were growing more and more rapidly, as the city’s major infrastructure, they act as an important role in life and production. With the progress of economic construction and social development, urban gas supply security led to more and more attention. However, frequent accidents in natural gas pipeline network posed a severe challenge to the gas supply system. It is of great importance for monitoring and scheduling the entire pipeline network to simulate the accident hydraulic conditions.This paper demonstrates the necessity of analysis of accident conditions for improving the reliability during the gas pipeline network design. This method can’t guarantee all users’ requirements when the accident occurred during the peak load operation. For this case, this paper establishes a model to simulate the operating conditions of the gas pipeline network under accident, and associates actual nodal flow with the nodal pressure, and establishes a segment function to the actual nodal flow. Then, the genetic algorithm(GA) is used to optimize the nodal flow, thus analyzing the scope and extent of the accident influence.With the increased requirements for the reliable supply of city gas, the use of multiple gas sources supply has become increasingly common. In addition, a large scale pipeline network is usually set to more than one regulator station. In this paper, the optimization goals are to make the total amount of gas supply and the supply coefficient of important users under pipeline network accident maximum, and the constraints are pipeline network hydraulic calculation basic equations, the requirements for gas flow and pressure of each node, the total amount of each gas source supply, and the maximum pressure of pipeline network. In addition, the decision variable is the pressure of each gas source. Thus, the optimal operation model to avoid gas source accident is built. Then, NSGA-Ⅱ is used to solve this model and the optimal scheduling policy under accident.The city gas pipeline network hydraulic calculation software is compiled, it can import Auto CAD network topology automatically, and calculate the normal and accidental operation conditions, and output pipeline network hydraulic calculation diagram. This software realizes the engineering quantity statistics and the output of report and image of the results. After the comparative analysis, the software has credible accuracy.