Transient Analysis of Variable-Pitch Pump Turbines

Abstract

A method of analyzing the transient behavior of a pump turbine with variable-pitch blades is presented. A series of equations that describe the behavior of the unit during the transient period is found by interpolation of the unit’s characteristic. These equations are combined with the method of characteristic solution to the waterhammer equations to describe the behavior of an entire system during a transient period. A complete performance characteristic of a variable-pitch pump turbine is presented. Example problems which utilize this characteristic illustrate the method of analysis. The examples prove that the variation in pitch of a unit’s blades is very important in predicting the head across the unit, the discharge through the unit, and the speed of the unit during a transient period.