Subatmospheric pressure protection for large diameter long distance pipeline system: A case study

Typical surge analysis of long distance pipelines involve pump power failure and startup at lift stations discharging into force mains. Utilities have several options for protecting pipeline systems from the effects of transients and surges. But how to select an effective surge protection strategy to design the system to withstand the stresses of transients is still a great challenge, especially for a high-lift, multiple peaks long distance system. This paper describes unique considerations that should be addressed when performing hydraulic transient analysis and recommending surge protection for water supply systems. Hydropneumatic tanks, surge tanks, vacuum breaker valves, surge-anticipator valves (SAV), surge relief valve (SRV), or both of them combined, and air valves will be discussed. Recent project examples and the effect of these new devices on surge protection in China will be presented.