Abstract：Aiming at the problem of accidental pump stop protection under the over-hump condition of the axial flow pumping station with siphon outlet channel, based on the basic theory of transient flow, a multi-objective optimization model of water hammer protection measures is established with the total gate closing time, gate fast closing stroke and fast closing time as decision variables, and the maximum reverse speed, maximum reverse flow rate, maximum water hammer pressure and minimum water hammer pressure as evaluation objectives. And chaos particle swarm optimization algorithm is used to solve this model. The results show that, compared with the standard particle swarm optimization algorithm, the chaos particle swarm optimization algorithm has strong particle diversity, high optimization ability and good algorithm stability, which effectively improves the water hammer protection effect of two-stage gate closing; the results of multiple optimization show that in the two-stage gate closing, the first stage closing speed and angle have a greater impact on the reverse speed, reverse flow and other indicators, while the gate closing law and gate flow have a greater impact on the manimum water hammer pressure. When the maximum over-hump water level of the pump station is less than 2 m, the strategy of ″14 s fast closing stroke 66%, 104 s slow closing stroke 34%″ can effectively protect the water hammer from stopping the pump water hammer.
