Distributed computing offers many advantages for all types of computational applications. Realizing heterogeneous simulation platforms may benefit from many facilities of distributed computing. However, distributing simulation components over a network raises many challenges concerning communications, data exchange, numerical stabilities and others. A well-known solution that addresses some of these challenges is the High Level Architecture (HLA). The HLA is an industry standard for distributed simulation and interoperability. So far the HLA has been used in industry for Discrete Event Simulations (DES). In this paper it is presented how the HLA can also be employed for continuous simulations. Two HLA specific algorithms for distributing explicitly coupled continuous simulation components over the network are presented. The simulation components follow the Functional Mock-up Interface (FMI) specification. The FMI is a specification for model exchange and co-simulation among simulation tools. Any simulation component conforming to FMI, generated from any of the more than forty simulation tools1 that are supporting or planning to support the FMI, can be considered in the proposed architecture.

PowerFactory is a powerful power system analysis tool used for simulating the electrical grid. 'Smart Grid' envisions a modernized electrical grid that uses communication to gather and act on information. The ever increasing communication and controls in power systems increases the complexity of the system. Co-simulation becomes essential to couple system simulators from different domains. This paper gives an overview of possible PowerFactory / Matlab coupling approaches. It further discusses the advantages and limitations of each of these. Additionally, an alternate coupling approach is suggested, its pros and cons are discussed. Two test cases have been implemented that highlight different advantages of the proposed method.

The energy system of the future is expected to be composed of a large variety of technologies and applications. However, the diverse nature of these components, their interlinked topology, and the sheer size of the system lead to an unprecedented level of complexity. Industry is confronted with severe problems in designing interoperable grid components, analyzing system stability, and improving efficiency. This paper describes the main challenges of continuous time-based and discrete event-based models of such cyber-physical energy systems. Using a characteristic test model, the scalability of the two approaches is analyzed. The results show the strengths and weaknesses of these two fundamentally different modeling principles that need to be considered when working with large scale cyber-physical energy systems.