Parallel computations for real-time simulation of large power system models is conventionally performed by using propagation delays embedded in line models. However, using the same approach to simulate distribution grids results in modelling inaccuracies, due to the short lengths of most distribution feeders. This paper illustrates the drawbacks of the delay-based parallelization technique by assessing the dynamic response of a large active distribution grid model and applies a delay-free parallelization technique (i.e. the State-Space-Nodal algorithm) to address inaccuracy issues inherent to the delay-based approach. ; QC 20161007