Impacts of Quadrature-axis Transient Reactance of Synchronous Condenser on Simulation Results of Rotor Angle Stability

Synchronous machines for large-capacity turbine generators generally have a solid-steel rotor structure. In power system dynamic analysis, it is known that the synchronous generator model considering quadrature axis transient reactance xq' is more accurate than a model that neglects xq' for a synchronous machine with a solid-steel rotor. However, in Japan, synchronous machine models neglecting xq' appears to be widely used for turbine generators. This is primarily because there is no significant difference between considering xq' and neglecting it in rotor angle stability analysis of synchronous generator (SG). On the other hand, the introduction of synchronous condenser (SC) is one measure to maintain system stability. SC may have solid-steel rotor structure, similar to that of large-capacity turbine generators, but it is not clear whether there is significant difference in rotor angle stability analysis between considering xq' and neglecting it. In this paper, the impacts of xq' of the SC on the rotor angle stability analysis are investigated. The results of the simulations show that there is a clear difference in rotor angle stability analysis of SC between considering xq' and neglecting it.