Surge protection for large diameter long distance flat pipeline system: A case study

For the long-distance water pipelines, the surge's damage is enormous, both high pressure and low pressure caused by water hammer can damage the pipeline and pump station. Specific to the large diameter long distance flat pipelines, the outstanding problem of water hammer is sub-atmospheric pressure, so the research about searching an effective protective measurement against surge is essential. In this paper, a long-distance water transmission project cross the Yellow River in Northwest China was illustrated. After analyzing the characteristics of the project, it worked out a unique surge protection approach for the large diameter long distance flat pipeline, which was used to withstand the stresses of transients in the project. And at the same time, it provided the available methods of surge protection for similar projects. Considering two cases, the pipeline was under or above the embankment, for each case the paper took hydropneumatic tank and air valves as the devices, and the pump trip hammer was simulated. According to the simulation results, it can be known that, for the long-distance flat pipeline, increase the elevation of some local pipeline, that would be helpful to reduce the surge's damage, and it could reduce the cost of surge protection. As the section under the riverbed is submerged, to ensure a reliable air intake for air valves, the paper also involved research about the air pipeline. What's more, it simulated the surge once there is a pump trip for lower flowrate while there is a pipeline breakage, and the reasonableness of the connecting pipelines was proved from the perspective of surge protection.