The power system is drastically changing towards new schemes at two different levels. At the high voltage level, requirements for exploitation in a large-scale of cheaper and cleaner renewable energies such as hydro, nuclear, onshore /offshore windfarms, solar power in the desert, etc., are merging for the transmission network. The competition at this level for the economic efficiency is through the wholesale electricity markets with reflection into the retail markets at the distribution level.

Renewable energy sources as distributed generations are penetrating increasingly, more smart equipment, like smart metering infrastructures, are being utilized, the infrastructures are also growing in terms of complexity and interdependency, and the communication system used for information flow are also being extensively developed as well as operational methods. Therefore development of advanced management systems, either equipment or strategies, is vital for power networks.

Deployment of any new systems and technologies and establishing appropriate control and management systems as well as new regulations requires accurate laboratory test and validation. Laboratory tests implies modelling and simulation of the systems, reproducing the system real behavior to study various scenarios.

There are many different types of simulation tools for modelling and planning for power systems, from large-scale high voltage transmission systems to low voltage distribution grids or even small controllers or devices, for a variety of applications, from transient analysis to long-term planning. Real time simulation provides a virtual environment of the systems in which new control strategies or technologies can be tested ex-ante before implementing in the real world system providing trustable real-like information on impacts and benefits. Real time simulation reproduces the behavior of a physical system through running its computer-based model at the same rate as actual time. In power systems, real-time simulation aims at reproducing with accuracy the behavior of the physical variables (e.g. voltages, currents, phases, etc). Real time simulation is typically used for reproducing the dynamics of fast phenomena, closed-loop testing of protection and control equipment, and generally all “what-if” analyses regarding transients.