Model complexity may have a significant impact on transient stability results of mixed AC/DC systems. The dynamics of various mixed AC/DC models with a focus on different gen-erator orders and multi-level modular converter (MMC) VSC-HVDC model types is investigated within this paper. MMC VSC-HVDC converter models are based on average value model (AVM) and simplified AVM, while 2nd, 3rd and 6th order generator models are formulated within the research. The paper also considers the impact of inner current control bandwidth. Based on the simulation result, substantial change over the transient stability result is seen with respect to differ-ent types of modelling complexity used within the research.