Risk-based dynamic security assessment for power system operation & operational planning

open6noAssessment of dynamic stability in a modern power system (PS) is becoming a stringent requirement both in operational planning and in on-line operation, due to the increasingly complex dynamics of a PS. Further, growing uncertainties in forecast state and in the response to disturbances suggests the adoption of risk-based approaches in Dynamic Security Assessment (DSA). The present paper describes a probabilistic risk-based DSA, which provides instability risk indicators by combining an innovative probabilistic hazard/vulnerability analysis with the assessment of contingency impacts via time domain simulation. The tool implementing the method can be applied to both current and forecast PS states, the latter characterized in terms of renewable and load forecast uncertainties, providing valuable results for operation and operational planning contexts. Some results from a real PS model are discussed.openCiapessoni, Emanuele; Cirio, Diego; Massucco, Stefano*; Morini, Andrea; Pitto, Andrea; Silvestro, FedericoCiapessoni, Emanuele; Cirio, Diego; Massucco, Stefano; Morini, Andrea; Pitto, Andrea; Silvestro, Federic

A Risk-Based Methodology and Tool Combining Threat Analysis and Power System Security Assessment

A thorough investigation of power system security requires the analysis of the vulnerabilities to natural and man-related threats which potentially trigger multiple contingencies. In particular, extreme weather events are becoming more and more frequent due to climate changes and often cause large load disruptions on the system, thus the support for security enhancement gets tricky. Exploiting data coming from forecasting systems in a security assessment environment can help assess the risk of operating power systems subject to the disturbances provoked by the weather event itself. In this context, the paper proposes a security assessment methodology, based on an updated definition of risk suitable for power system risk evaluations. Big data analytics can be useful to get an accurate model for weather-related threats. The relevant software (SW) platform integrates the security assessment methodology with prediction systems which provide short term forecasts of the threats affecting the system. The application results on a real wet snow threat scenario in the Italian High Voltage grid demonstrate the effectiveness of the proposed approach with respect to conventional security approaches, by complementing the conventional "N - 1" security criterion and exploiting big data to link the security assessment phase to the analysis of incumbent threat

Risk Assessment Techniques for Civil Aviation Security

Following the 9/11 terrorists attacks a strong economical effort was made to improve and adapt aviation security, both in infrastructures as in airplanes. National and international guidelines were promptly developed with the objective of creating a security management system able to supervise the identification of risks and the definition and optimisation of control measures. Risk assessment techniques are thus crucial in the above process, since an incorrect risk identification and quantification can strongly affect both the security level as the investments needed to reach it. The paper proposes a set of methodologies to qualitatively and quantitatively assess the risk in the security of civil aviation and the risk assessment process based on the threats, criticality and vulnerabilities concepts, highlighting their correlation in determining the level of risk. RAMS techniques are applied to the airport security system in order to analyse the protection equipment for critical facilities located in air-side, allowing also the estimation of the importance of the security improving measures vs. their effectiveness

Electricity infrastructure enhancement for the security of supply against coordinated malicious attacks

© 2016 IEEE. The impact of coordinated malicious attacks may be dramatically severe and may yield a wide area blackout. A preventive measure is enhancing the infrastructure through investment. Due to limited budget, a decision making is required to select the best possible options, considering cost/benefit ratio. We designed a time-step simulation framework representing the evolution of post-contingency failures and load/system restoration. System unserved energy is translated into economic losses. Different enhancement options can be compared in terms of benefit (reduction in the cost of unserved energy) and of cost (investments needed) to eventually rank them. The simulation framework also provides a way to derive an optimal lost load recovering strategy to accelerate system restoration. In this paper the simulation framework is applied to a real network (Austrian transmission grid) to evaluate the technical and economic impacts of a coordinated malicious attack

CCTV Surveillance System, Attacks and Design Goals

Closed Circuit Tele-Vision surveillance systems are frequently the subject of debate. Some parties seek to promote their benefits such as their use in criminal investigations and providing a feeling of safety to the public. They have also been on the receiving end of bad press when some consider intrusiveness has outweighed the benefits. The correct design and use of such systems is paramount to ensure a CCTV surveillance system meets the needs of the user, provides a tangible benefit and provides safety and security for the wider law-abiding public. In focusing on the normative aspects of CCTV, the paper raises questions concerning the efficiency of understanding contemporary forms of ‘social ordering practices’ primarily in terms of technical rationalities while neglecting other, more material and ideological processes involved in the construction of social order. In this paper, a 360-degree view presented on the assessment of the diverse CCTV video surveillance systems (VSS) of recent past and present in accordance with technology. Further, an attempt been made to compare different VSS with their operational strengths and their attacks. Finally, the paper concludes with a number of future research directions in the design and implementation of VSS

Developing ‘Nexus Capabilities’: towards transdisciplinary methodologies

Draft discussion paper (initially without references) for review at an ESRC Nexus Network workshop, to be held at the University of Sussex, 29-30th June 2015. Many ideas summarised here have been further developed and explored over the ten-year research programme of the STEPS Centre

Precaution in the governance of technology

Equally at national and the highest international levels, few issues in technology governance are more vexed than those around the precautionary principle. Often using colourful rhetoric – and frequently paying scant attention to the substantive form taken by precaution in any given setting, even ostensibly academic analyses accuse precautionary approaches of being ‘dangerous’, ‘arbitrary’, ‘capricious’ and ‘irrational’ – somehow serving indiscriminately to ‘stifle discovery’, ‘suppress innovation’ and foster an 'anti-technology’ climate. The widely advocated alternative is ‘science based’ risk assessment – under which single aggregated probabilities are assigned to supposedly definitively-characterised possibilities and asserted to offer sufficient representations of the many intractable dimensions of uncertainty, ambiguity and ignorance. The high economic and political stakes combine with their expediency to entrenched institutional and technological interests, to intensify these arguments. Amidst all the noise, it is easy to miss the more balanced, reasonable realities of precaution. By reference to a large literature on all sides of these debates, this paper shows how these pressures are not only misleading, but themselves seriously unscientific – leading to potentially grave vulnerabilities. Experience over more than a century in technology governance, shows that the dominant issues are not about calculation of probabilities, but about the effects of power in innovation and regulatory systems, the need for balanced consideration of alternative options, scrutinising claimed benefits as much as alleged risks and always being vigilant for the ever-present possibility of surprise. In this light, it is not rational to assert that incertitudes of many difficult kinds must always take the convenient forms susceptible to risk assessment. To invoke the name of science as a whole, in seeking to force such practices, is gravely undermining of science itself. And these pressures also seriously misrepresent the nature of innovation processes, in which the 2 branching evolutionary dynamic means that concerns over particular trajectories simply help to favour alternative innovation pathways. Precaution is about steering innovation, not blocking it. It is not necessarily about ‘banning’ anything, but simply taking the time and effort to gather deeper and more relevant information and consider wider options. Under conditions of incertitude to which risk assessment is – even under its own definition – quite simply inapplicable, precaution offers a means to build more robust understandings of the implications of divergent views of the world and more diverse possibilities for action. Of course, like risk assessment, precaution is sometimes implemented in mistaken or exaggerated ways. But the reason such a sensible, measured approach is the object of such intense general criticism, has more to do with the pervasive imprints of power in and around conventional regulatory processes, than it does with any intrinsic features of precaution itself. Whilst partisan lobbying is legitimate in a democracy as a way to advance narrow sectoral interests, it is unfortunate when such rhetorics seek spuriously to don the clothing of disinterested science and reason in the public interest. Taking the best of all approaches, this paper ends by outlining a general framework under which more rigorous and comprehensive precautionary forms of appraisal, can be reconciled with riskbased approaches under conditions where these remain applicable. A number of practical implications arise for innovation and regulatory policy alike, spanning many different sectors of emerging technologies. In the end, precaution is identified to be about escaping from technocratic capture under which sectoral interests use narrow risk assessment to force particular views of the world. What precaution offers to enable instead is more democratic choice under ever-present uncertainties, over the best directions to be taken by innovation in any given field

The most frequent N-k line outages occur in motifs that can improve contingency selection

Multiple line outages that occur together show a variety of spatial patterns in the power transmission network. Some of these spatial patterns form network contingency motifs, which we define as the patterns of multiple outages that occur much more frequently than multiple outages chosen randomly from the network. We show that choosing N-k contingencies from these commonly occurring contingency motifs accounts for most of the probability of multiple initiating line outages. This result is demonstrated using historical outage data for two transmission systems. It enables N-k contingency lists that are much more efficient in accounting for the likely multiple initiating outages than exhaustive listing or random selection. The N-k contingency lists constructed from motifs can improve risk estimation in cascading outage simulations and help to confirm utility contingency selection

The political economy of electricity system resource adequacy and renewable energy integration: A comparative study of Britain, Italy and California

The need to integrate growing shares of variable renewable resources, like solar and wind, into the power system has initiated a new wave of resource adequacy policy reforms. Securing adequate resources on the system, particularly flexible and peak capacity, is indeed crucial for ensuring long-term grid reliability amid increased supply variability. While extensively explored from a techno-economic perspective, the political economy drivers and implications of these changes are frequently overlooked. Yet, power system evolution is not merely shaped by logics of techno-economic optimisation, it is also inherently political, rooted in specific liberalisation histories, political and institutional settings. This paper contributes to the literature by conducting a comparative political economy analysis of recent resource adequacy reforms in Britain, Italy, and California. It explores how differences in the technical and political economy contexts of these jurisdictions affected their strategies for securing resource adequacy capacity and investment between 2013 and 2021. Conclusions draw on the analysis of over 134 policy documents and 53 in-depth interviews with power system stakeholders. All jurisdictions introduced significant changes in resource adequacy policy, including explicit out-of-market mechanisms to remunerate resource adequacy capacity. The energy transition is thus reconfiguring state-market relations in the power sector, even in traditionally liberal countries. However, variation exists in the scope of reform, mechanism designs, policy trade-offs, and technological outcomes. This stems from context-specific political priorities, state-market relations, national and multi-level governance arrangements, market structures and stakeholder interests. This has important implications for power sector governance, as discussed in this paper