Adaptive Quality of Service Provisioning for an Efficient and Resilient Operation of Smart Distribution Grids

• Applicants: Professor Dr.-Ing. Reinhard German; Professor Dr. Sebastian Lehnhoff
• Subject Area: Electrical Energy Systems, Power Management, Power Electronics, Electrical Machines and Drives ; Security and Dependability, Operating-, Communication- and Distributed Systems
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 470145579

The operation of modern energy systems is based on a large number of measurement, control and automation tasks for monitoring and operating extensively distributed resources. For these tasks, e.g. voltage stability monitoring or state estimation, different quality of service (QoS) requirements must be guaranteed, as they serve as the basis for higher optimization functions that realize reliable, efficient and forward-looking overall system operation. In transmission systems, a dedicated and high-performance communication infrastructure allows a parallel execution of these communication-intensive functions and services. In the course of the expansion of renewable energies at lower voltage levels of the distribution networks and the shift of system responsibility to (operators of) these plants and systems, similar functions and services must also be implemented at the distribution network level in Smart Grids – so-called ”Smart Grid Services” (SGSs). A comparable digitalization as in the transmission grid does not exist due to different planning approaches, but mainly for cost reasons. Therefore, in addition to the optimization of energy-related processes in the distribution networks, reliable, efficient, adaptive and forward-looking planning and operation of SGSs via heterogeneous and more resource-limited communication systems are required. To our knowledge, there is currently no suitable method for an adaptive QoS provisioning that both takes into account dynamically changing QoS requirements and priorities of SGSs and is able to guarantee the QoS requirements of critical services. In this project, we will therefore conduct research on online reconfiguration methods based on a two-step QoS-provisioning approach: At a first level, discrete optimization is used to find an allocation of SGSs to available servers and allocation of flows to paths through the communication network based on a topological view of the compute, storage, and communication facilities. At this level, all flows are simply characterized by bit rates. At a second level, Network Calculus is used to ensure analytically that all critical SGSs can meet their QoS requirements. For this purpose, traffic characterizations of flows are more detailed and incorporate also burstiness and the behavior of network elements can be described in more detail but still on an abstract level by service curves. If QoS requirements of critical SGSs are violated, iterations over the two steps are necessary. The overall effect of the two-step approach will then be assessed by simulation in order to validate whether the two-step QoS-provisioning approach works well and to check the impact of the allocation on the non-critical SGSs. The approach then needs to be extended in order to take the conditions during reconfiguration into account as well.

• DFG Programme: Research Grants