Convergent Interoperability Stack for Smart Grid ICT Infrastructures

The "smart grid", i.e., the combination of an infrastructure for the transmission and distribution of electrical energy with a corresponding information and communication technology (ICT) infrastructure, is intended to ensure the stability of the power grid in the future while at the same time enabling the integration of renewable (mostly volatile) energy sources.The basic problem here is primarily the strong heterogeneity of the stakeholders (energy suppliers, grid operators, customers, equipment manufacturers, system operators, authorities, etc.). An ICT infrastructure must enable all these groups to run their respective applications under defined quality conditions (limited latency, required availability, etc.).Despite many standardization efforts, a generic approach (independent of a specific use case) for the interoperability of all these subsystems is still missing. In closed environments such as in home automation, frameworks exist that provide functionalities such as a common data model or consistent addressing for nodes.However, such frameworks are hardly suitable in the highly distributed smart grid. Therefore, this dissertation aims at a lightweight solution without central frameworks. The required middleware functions are to be mapped to a suitable protocol stack, which essentially has an end-to-end characteristic and requires few central services.Thus, an open meta-architecture for a distributed “system of systems” can be created with minimal access barriers for the participating stakeholders. The protocol stack for data exchange between stakeholders must cover the necessary functionality to ensure interoperability of the stakeholders’ applications. The algorithmic base therefore includes data structures as well as state information and protocol sequences.Finally, the used protocol stack is also validated and evaluated in this dissertation, based on concrete scenarios. The evaluation analyses the results of the executed test scenarios with respect to scalability, coupling strength, rights management, concurrency, trust, security, addressing, statefulness, overlay architectures, and virtualization possibilities.