The Closing Law Optimizing Nvestigation Of Turbine Guide Vane With Howell-bunger And Ring Jet Valve

The transient process of hydropower plant is a kind of temporary phenomenon,it usually appears when units operating condition change.Hydropower plants often implement many tasks,such as power generation,peak shaving,frequency control,etc.The load change is frequent,especially for load rejection that may cause serious accident,so it should be given special concern.Simulation study on the transient process can predict preferably control parameters in transient process,it avoid the occurrence of some undesirable situation.Optimization of guide vane closing law can reduce pressure rise in penstock and spiral case,the calculating results provide the basis for the strength optimization design of related structure components.For projects which install howell-bunger valve instead of surge tank to control pressure rise in penstock,there are already many applications in worldwide distinct,but still blank in China.So,it is necessary to study the matching way of guide vane and discharge release valve for hydropower plant.Base on pressure transient theory and method of characteristic curve,found numerical model of power generating system,two closing laws of guide vane are given respectively as per discharge release valve close normally and refuse to close.First of all,some basic calculation cases are given according to the arrangement of hydropower project.When discharge release valve close normally,the closing optimization have finished as per guide vane adopting one/two/three straight closure,the conclusion is that three straight closure of guide vane is the best matching way with release valve.Secondly,perform the applicable investigation of matching way for controlling minimum pressure at draft tube inlet and penstock.The conclusion is that it apply these conditions,calculation results meet requirements of the transient process control.Finally,when discharge release valve refuse to close,the applicable investigation of guide vane closing law has also finished,the conclusion is that three straight closure of guide vane is not applied this situation.After performing the investigation of matching way again,the new matching way is given,finish the matching investigation of guide vane and release valve.