State description of cyber-physical energy systems

Abstract

The integration of ICT into power systems has increased the interdependencies between the two systems. The operation of power system depends on several ICT-enabled grid services which manifest the interdependencies. ENTSO-E system state classification is a tool that is widely used by operators to determine the current operational state of the power system. However, it does not adequately describe the impact of ICT disturbances on the operation of the power system. Despite their interconnections, the operational states of both systems have been described separately so far. This paper bridges the well-established ENTSO-E systems state classification with an ICT system state classification, forming a new model considering the state classification of the ICT-enabled grid services. The model is developed by first identifying the ICT-enabled services, remedial actions and the respective performance requirements that are required by the power system. Then the states of these services are specified based on the supporting ICT system. The resulting joint state description shows how performance degradation of ICT-enabled services (introduced by disturbances) can affect the operation of the interconnected power system. Two case studies of such ICT-enabled services, namely state estimation and on-load tap changer control, are investigated in terms of how their operational states affect the states of the power system. A third case study highlights the interdependencies that exist between the services. These case studies demonstrate the interdependencies that exist between power and ICT systems in modern cyber-physical energy systems, thus highlighting the usage of a unified system state description.

Impact of ICT Latency, Data Loss and Data Corruption on Active Distribution Network Control

“…In [8], the operational states of the ICT-enabled grid services were introduced as a means to capture their performance in a generalized manner. The authors in [7], [23] discuss the operational state classification for two services, namely state estimation, and on-load tap changer control.…”

“…Additionally, two exemplary fallback strategies to mitigate the consequences of data loss are analyzed. Finally, the results are used to identify concrete thresholds for three operational service states (i.e., normal, limited, and failed) in order to summarize the performance of the ADN control service as described in [8].…”

“…This improves the interpretability of the results and provides an overview of the performance of service for system operators and planners. The operational state of a service, presented in [8] and demonstrated in [7], can be classified as normal, limited or failed. These operational states denote the performance of the service.…”

“…The low ICT penetration on these grid levels implies that only few data is generated and transmitted. However, the increasing penetration of ICT in power systems in the future can lead to potential new risks due to controllers' dependency on communication as well as the propagation of disturbances between the domains [8].…”

Ancillary services and electric vehicles: An overview from charging clusters and chargers technology perspectives

“…Similarly, energy arbitrage and seasonal balancing are believed to be necessary services to cope with the unpredictability of RESs [142,143]. Additionally, emergency power and black-start capability are programmed for blackouts (according to ENTSO-E) [144], or to provide emergency power to areas affected by local emergencies [130].…”