  Smart grid systems are characterized by high complexity due to interactions
between a traditional passive network and active power electronic components,
coupled using communication links. Additionally, automation and information
technology plays an important role in order to operate and optimize such
cyber-physical energy systems with a high(er) penetration of fluctuating
renewable generation and controllable loads. As a result of these developments
the validation on the system level becomes much more important during the whole
engineering and deployment process, today. In earlier development stages and
for larger system configurations laboratory-based testing is not always an
option. Due to recent developments, simulation-based approaches are now an
appropriate tool to support the development, implementation, and roll-out of
smart grid solutions. This paper discusses the current state of
simulation-based approaches and outlines the necessary future research and
development directions in the domain of power and energy systems.
