Study on Two Dynamic Aggregation Algorithms of Coherent Generators

Dynamic aggregation of coherent generators is the main step in constructing dynamic equivalent model of power systems. In this paper two typical algorithms of coherent generators dynamic aggregation are reviewed briefly, the first model is traditional frequency domain algorithm, namely the generator terminal bus aggregation algorithm which uses the iterative process in frequency domain to derive the parameters of equivalent generator, the second model is weighted-average algorithm based on engineering, the approach frequency domain is more complicated so that it is considerable calculation and time consuming than the weighted-average method when two models are applied to large-scale power systems. For validation purpose, two models are tested on IEEE-39 bus system and the simulation results indicate that two equivalent system models can preserve the main dynamic characteristics of the original system well, on the other hand, the frequency domain model is an accuracy model so that it is suitable for precise analysis to power systems, the weighted average model is more deviation than the frequency domain model so that it is used to practical engineering.