The critical infrastructure is constantly under cyber and physical threats. Applying security controls without guidance or traceability can create a false sense of security. Security standards facilitate security knowledge and control best practices in a more systematic way. However, the number of standards is continually increasing. Product providers that operate in multiple geographical regions often face the obligation to comply with multiple standards simultaneously. This introduces the problem of the convenient interpretation of different standards. Thus, a comprehensive analysis of the requirements from different security standards and guidelines applicable to the smart grid has been performed to detect similarities that can be shaped into entities of the conceptual model for requirement representation. The purpose of the model—presented in a form of a Unified Modeling Language (UML) class diagram—is to give product providers a canonical way to map requirements from arbitrary standards, guidelines, and regulations and accelerate the cross-standard compliance readiness by defining priority for requirement implementation. In addition, the research showed that multiple vectors should impact the priority of the implementation of the security controls defined through the requirements: domain affiliation, the essence of the requirement, associated threats, risks, and social dependencies between actors involved in the implementation. To examine the model correctness, NISTIR 7628—de facto smart grid standard—was used to provide insights into how the model would be used for requirements implementation tracking. The structure of individual requirements was analyzed to detect the building blocks and extract relevant parts that can be mapped to the model components. Further, all requirements were classified into one of the defined domains to provide the basis for referencing similar requirements from different standards. Finally, one arbitrary requirement was used to demonstrate model usage, and depict all available information that can be provided to the users in a custom-made scenario where the need arises to have simultaneous alignment with three standards—NISTIR 7628, NIST 800-53, and IEC 62443-3-3.

Power grids are constantly evolving, and data changes are increasing. Operational technology (OT) is controlled by IT technologies in smart grids, where changes in the physical world impose changes in the software data model, as well as the continuous generation of data points, resulting in time series datasets. The increased need for processing large amounts of data combined with requirements to maintain and increase overall performances has created a significant challenge for traditional database solutions and relational database models. The main idea of this paper was to find and propose a graph model that will allow the retrieval of historical connectivity in a reduced time complexity. Furthermore, the research question was addressed by evaluating three different approaches where the results provide a foundation for the proposed design guidelines related to optimizing graph-based databases for a modern smart grid system. The results of the experiments demonstrated reduced time complexities from 3 to 5 times depending on the typical industry usage patterns and the selected graph model. This suggests that the design decision may severely affect the outcome for given smart grid use cases when using historical features in OT technologies. Therefore, the main contribution of the research is the proposed guidelines on how to design an optimal graph model that satisfies the described smart grid requirements.