A risk assessment framework for the smart grid

Author(s):  
Riadh W. Y. Habash ◽  
Voicu Groza ◽  
Dan Krewski ◽  
Greg Paoli
Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3428
Author(s):  
Amitkumar V. Jha ◽  
Bhargav Appasani ◽  
Abu Nasar Ghazali ◽  
Nicu Bizon

The smart grid (SG), which has revolutionized the power grid, is being further improved by using the burgeoning cyber physical system (CPS) technology. The conceptualization of SG using CPS, which is referred to as the smart grid cyber physical system (SGCPS), has gained a momentum with the synchrophasor measurements. The edifice of the synchrophasor system is its communication network referred to as a synchrophasor communication network (SCN), which is used to communicate the synchrophasor data from the sensors known as phasor measurement units (PMUs) to the control center known as the phasor data concentrator (PDC). However, the SCN is vulnerable to hardware and software failures that introduce risk. Thus, an appropriate risk assessment framework for the SCN is needed to alleviate the risk in the protection and control of the SGCPS. In this direction, a comprehensive risk assessment framework has been proposed in this article for three types of SCNs, namely: dedicated SCN, shared SCN and hybrid SCN in an SGCPS. The proposed framework uses hardware reliability as well as data reliability to evaluate the associated risk. A simplified hardware reliability model has been proposed for each of these networks, based on failure probability to assess risk associated with hardware failures. Furthermore, the packet delivery ratio (PDR) metric is considered for measuring risk associated with data reliability. To mimic practical shared and hybrid SCNs, the risk associated with data reliability is evaluated for different background traffics of 70%, 80% and 95% using 64 Kbps and 300 Kbps PMU data rates. The analytical results are meticulously validated by considering a case study of West Bengal’s (a state in India) power grid. With respect to the case study, different SCNs are designed and simulated using the QualNet network simulator. The simulations are performed for dedicated SCN, shared SCN and hybrid SCN with 64 Kbps and 300 Kbps PMU data rates. The simulation results are comprehensively analyzed for risk hedging of the proposed SCNs with data reliability and hardware reliability. To summarize, the mean risk with data reliability (RwDR) as compared to the mean risk with hardware reliability (RwHR) increases in shared SCN and hybrid SCN by a factor of 17.108 and 23.278, respectively. However, minimum RwDR increases in shared and hybrid SCN by a factor of 16.005 and 17.717, respectively, as compared to the corresponding minimum RwHR. The overall analysis reveals that the RwDR is minimum for dedicated SCN, moderate for shared SCN, and highest for hybrid SCN. 


Buildings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 247
Author(s):  
Charlotte Svensson Tengberg ◽  
Carl-Eric Hagentoft

Design-build contractors are challenged with the task of minimizing failure risks when introducing new technical solutions or adapting technical solutions to new conditions, e.g., climate change. They seem to have a disproportional trust in suppliers and their reference cases and might not have adequate resources or methodologies for sufficient evaluation. This creates the potential for serial failures to spread in the construction industry. To mitigate this, it was suggested that a predefined risk assessment framework should be introduced with the aim of providing a prequalification and requirements for the use of the technical solution. The objectives of this paper are to develop a comprehensive risk assessment framework and to explore the framework’s potential to adequately support the design-build contractor’s decisions. The framework uses qualitative assessment, relying on expert workshops and quantitative assessments, with a focus on simulation and probabilities. Tollgates are used to communicate risk assessments to the contractor. The framework is applied to a real-life case study of construction with a CLT-structure for a Swedish design-build contractor, where exposure to precipitation during construction is a key issue. In conclusion, the chosen framework was successful in a design-build contractor context, structuring the process and identifying difficulties in achieving the functional requirements concerning moisture. Three success factors were: documentation and communication, expert involvement, and the use of tollgates. Recommendations to the design-build contractor on construction of CLT structure are to keep construction period short and to use full weather protection on site.


2021 ◽  
Vol 25 (4) ◽  
pp. 1144-1162
Author(s):  
Milad Alipour-Bashary ◽  
Mehdi Ravanshadnia ◽  
Hamidreza Abbasianjahromi ◽  
Ehsan Asnaashari

2018 ◽  
Vol 69 (7) ◽  
pp. 1159 ◽  
Author(s):  
P. Bayliss ◽  
C. M. Finlayson ◽  
J. Innes ◽  
A. Norman-López ◽  
R. Bartolo ◽  
...  

The internationally important river–floodplains of the Kakadu Region in northern Australia are at risk from invasive species and future sea-level rise–saltwater inundation (SLR–SWI), requiring assessments of multiple cumulative risks over different time frames. An integrated risk-assessment framework was developed to assess threats from feral animals and aquatic weeds at three SLR-scenario time frames (present-day, 2070 and 2100) to natural (magpie goose habitats), cultural (indigenous hunting–fishing sites) and economic (tourism revenue less invasive species control costs) values. Probability density functions (pdfs) were fitted to spatial data to characterise values and threats, and combined with Monte Carlo simulation and sensitivity analyses to account for uncertainties. All risks were integrated in a Bayesian belief network to undertake ‘what if’ management-scenario analyses, and incorporated known ecological interactions and uncertainties. Coastal landscapes and socio-ecological systems in the region will be very different by 2100 as a result of SLR; freshwater ecosystems will transform to marine-dominated ecosystems and cannot be managed back to analogue conditions. In this context, future invasive-species risks will decrease, reflecting substantial loss of freshwater habitats previously at risk and a reduction in the extent of invasive species, highlighting the importance of freshwater refugia for the survival of iconic species.


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