Investigation Of The Influence Of The Turbine Wicket Gates Closure Law Pattern On The Water Hammer Effect During Turbine Off-Design Operation

Hydraulic transients are accelerated by the wicket gate closing in hydroelectric power plants. When the wicket gate is closed, there is a sudden change in velocity due to the closure. Therefore, a study has been carried out here, wherein water hammers on different hydropower components use optimum closure laws: Fast closure laws, slow closure laws, and instant load rejection. Hammer V10i software was used to investigate the phenomenon of pressure transient. The results show that the maximum transient pressure is strongly influenced by a very short closing time and was increased to 41.24% from the slow to the fast closure. Furthermore, the results from instant load rejections reveal that the transient pressure will be less than the fast and slow closure. So, the closing law selection can positively influence the entire hydropower plant system. Furthermore, the results show that there was a decrease in pressure near the turbine during the different load rejections, Fast closure, slow closure, and instant load rejection, where 57.7%, 15%, and 0.46%, respectively, and the decrease in turbine rotation speed were as 5.1%, 60%, and 24% respectively. Moreover, results reveal that maximum and minimum flow variation reached -29.75% and 41.2% during the fast closure.