The numerical representation of pump-turbine performance characteristics
This thesis investigates the hydraulic transient analysis of hydro-power plants with particular emphasis being placed on the turbine and pump-turbine boundary conditions. A lack of suitable data, in the form of the machine performance characteristics, during the early stages of a hydro-power station's development led to the investigation of alternative sources of performance characteristics, not based on the testing of a hydraulically similar model turbine. Two methods of obtaining turbine performance characteristics were developed, one based on the published performance characteristics of typical reaction turbines and the second based on performance characteristics from a turbine of similar specific speed. The problems particular to the unit parameter representation of four quadrant reversible pump-turbine performance characteristics for use in hydraulic transient analyses were investigated. A review of alternative forms of representation led to the solution of the pump-turbine boundary based on a modified unit parameter representation. The method reduces the multi-variable problem of the pump-turbine boundary condition to that of a single variable. The solution algorithm is equally successful for use with standard turbines. A computer program for the analysis of hydraulic transients in hydro-power plants was developed and comparisons with site recordings, taken during a full load rejection at a typical pumped storage scheme, made in order to verify the operation of the computer program. Further simulations demonstrate the combined boundary condition of turbine and relief valve.