Study on the multi-objective optimization of reliability and operating cost for natural gas pipeline network

The development of natural gas pipeline network towards larger scale and throughput has encouraged better reliability of the pipeline network to satisfy transportation requirement. For a natural gas pipeline network with a variety of components and complicated topology, a multi-objective optimization model of both reliability and operating cost was proposed. Failure of each component and the state of pipeline network under failure conditions were considered and minimum cut set method was used to calculate the reliability of the pipeline network. The variables to be determined for the optimization objectives are the rotating speed of compressors and the opening of valves. The solving procedure of the proposed model is provided based on Decoupled Implicit Method for Efficient Network Simulation (DIMENS) method and NS-saDE algorithm. The validity of the optimization model was evaluated by its application on a complicated pipeline network. The results illustrated that the optimization model depicted the relative relationship between reliability and operating cost for different throughput, by which the operation scheme with both satisfying reliability and operating cost could be obtained. Also, the customer reliability and the impact of the failure of each pipeline on the whole network could be evaluated quantitatively to identify the consumers and pipelines of maintenance priority. The pipeline network reliability could be improved through proper monitoring and maintenance of these consumers and pipelines.