A novel pelton turbine model for water hammer analysis

english

2009

volume 55, issue 6

Univerza v Ljubljani, Fakulteta za strojništvo

This paper presents a novel Pelton turbine model for water hammer analysis. Water hammer phenomena have been investigated in Perućica high-head hydropower plant (HPP), Montenegro. During its first phase of modernisation and refurbishment new distributors (needle valves) have been installed on the first two Pelton turbine units. Closure of the Pelton turbine distributors for the case of emergency shut-down and load rejection under governor control is modelled by two different closing laws i.e. the two-speed closing law and the law that considers actual (measured) needle stroke. Dissipation torques in turbine housing and shaft bearings are considered in the model. Stop procedure of the turbine unit is also investigated. Numerical results using the standard quasi-steady friction model and the convolution based unsteady friction model for different distributor closing laws are compared with the results of measurements. The agreement between computed and measured results is reasonable. It is shown that the effect of unsteady friction on water hammer events in Perućica HPP is of little importance (slow varying transients).

14.07.2011