Calculation of Four-Quadrant Characteristics of Turbines

For handling of extreme operation conditions of turbines or in cases of disturbance or breakdown of turbine plants, it is important to have knowledge about the characteristics far away from the design point. This paper explains the attempt of a calculation method for computing the complete four-quadrant characteristics of a turbine on the basis of the mean section cascade characteristics of the blading. The cascade characteristics for normal and backward flow are pointed out and with these are calculated the stage characteristic lines for perfect gas. The turbine characteristics are computed by superimposition of the stage characteristics and compared to measuring results.