An improved analytical method of generators aggregation based on structure preserving technique

This paper presents an improved analytical method of coherency generating unit aggregation. Firstly, the presented method eliminates voltage deviations resulted from aggregating generators moved to the common bus. Then, the time domain model of generating units with detailed models, based on the coefficient matrices structure preservation, is deduced. The key idea of this model is to keep the same values between the sum of current phasors on each axis of synchronous plane and equivalent generating one. At last, parameters of the equivalent generating unit are directly derived. Compared with traditional methods such as transfer function fittings in frequency domain, the new method can be applied to generators of different structures or complexities. Various simulation results demonstrated a satisfactory match between the original system and the equivalent system.