Abstract
A number of studies have been made on the hunting phenomena of synchronous machines. However, most of them have been concerned with the mathematical analysis based on equivalentcircuit models of machine and system, and experimental studies are quite rare. Besides, few papers have treated the phenomena from the viewpoint of internal airgap fluxes which actually govern the machine behaviors.
This paper describes the experimental results on hunting phenomena of synchronous generators caused by a fast-acting AVR (Automatic Voltage Regulator) in a laboratory-model one-machine/infinite-bus power system. Changes of airgap fluxes in the process of hunting phenomena are measured by a search coil wound around a stator tooth top of the tested synchronous generator and are examined. The interaction is made clear between field fluxes and quadrature-axis fluxes both of which directly influence the hunting phenomena. The results obtained are confirmed by simulation studies. Thus, the relationship between system stability and machine fluxes is given a clearer understanding than before.
