A modified balanced truncation method and its application to model reduction of power system

The balanced truncation method (BTM) can make the reduced model preserve the controllability, observability, stability, and dynamic response of the original model, but some steady-state deviations between the reduced model and the original model exist. On the premise of keeping the merits of the BTM, this paper modifies the BTM to narrow the deviations by introducing a gain factor into the transfer function matrix of the reduced model to adjust the steady-state value of the reduced model, but not to change the dynamic behavior. For verifying the modified BTM, we apply the method to the model reduction of a typical two-machine system. The testing results indicate that the modified method can decrease the deviations, lower the order of the system, and retain dynamic behaviors of the original model.