2019 Other Open Access

Enhanced power grid evaluation through efficient stochastic model-based analysis
Masetti G.
The electrical infrastructure can be considered nowadays as a meta-critical infrastructure: in fact it is the basis for almost all the critical infrastructures a modern nation can have, such as water, oil, gas and transportation. This implies that its correct operation is a fundamental requirement to the correct operation of the critical infrastructures that depend on it. To allow pervasive control and monitoring towards resilience and performance enhancements, the Smart Grid is emerging as a convergence of information and commu- nication technology with power system engineering. In particular, the ever increasing level of distributed energy resources penetration calls for more and more sophisticated monitoring and control facilities. So, studying the influence of distributed energy resources, of new control policies and ICT on the dependability of distribution grids offers valuable insights on how to improve the design of Smart Grids. In addition to standard dependability measures such as reliability and availability, among greatly relevant measures specifically defined for electrical distribution systems there are the voltage quality and the energy required, but not supplied, by the distribution system. A popular approach to assess electrical distribution specific measures, in presence of failures or attacks to the ICT system and/or to the electric in- frastructure, is the stochastic model-based analysis. Although several studies have been already proposed, the research in this context still faces a number of challenges, mainly due to the need: i) to consider both the ICT sub- system and the controlled electrical infrastructure, to properly account for (inter)dependencies through which operations (and failures/attacks) propa- gate; ii) to model and analyze the SG components at a sufficiently detailed level of abstraction, targeting realistic representation of their structure and behavior in view of promoting accuracy of the assessment itself. Both nomi- nal and a variety of faulty behaviors are to be investigated, since the interest is on assessing resilience and quality related attributes; iii) to tackle realistic segments of SG in terms of topology size, to make the evaluation study of real interest to stakeholders involved in the field. To cope with all these needs results in huge and complex models, to be typically defined in a modular fashion and requiring sophisticated composi- tional operators. Moreover, model solution through simulation-based eval- uation becomes unavoidable in presence of non-Markovian behavior of the involved components, thus preventing the use of analytical approaches. Given the above premises, the stochastic model-based analysis of realistic SG topologies is a research area where further investigations and enhance- ments are highly desirable. In this context, this thesis offers contributions in the direction of promoting efficient evaluation of SG in realistic scenarios from a resilience perspective.

2020 Conference article Open Access

Trading dependability and energy consumption in critical infrastructures: Focus on the rail switch heating system
Chiaradonna S., Di Giandomenico F., Masetti G.
Traditionally, critical infrastructures demand for high dependability, being the services they provide essential to human beings and the society at large. However, more recent attention to cautious usage of energy resources is changing this vision and calls for solutions accounting for appropriate multi-requirements combinations when developing a critical infrastructure. In such a context, analysis supports able to assist the designer in envisioning a satisfactory trade-off among the multi-requirements for the system at hand are highly helpful. In this paper, the focus is on the railway sector and the contribution is a stochastic model-based analysis framework to quantitatively assess trade-offs between dependability indicators and electrical energy consumption incurred by the rail switch heating system.Moving from a preliminary study that concentrated on energy consumption only, the analysis framework has been extended to become a solid support to devise appropriate tuning of the heating policy that guarantees satisfactory trade-offs between dependability and energy consumption. An evaluation campaign in a variety of climate scenarios demonstrates the feasibility and utility of the developed framework.Source: 25th IEEE Pacific Rim International Symposium on Dependable Computing, pp. 150–159, Perth, Australia, 01/12/2021
DOI: 10.1109/prdc50213.2020.00026
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