An Assessment of PIER Electric Grid Research 2003-2014 White Paper

This white paper describes the circumstances in California around the turn of the 21st century that led the California Energy Commission (CEC) to direct additional Public Interest Energy Research funds to address critical electric grid issues, especially those arising from integrating high penetrations of variable renewable generation with the electric grid. It contains an assessment of the beneficial science and technology advances of the resultant portfolio of electric grid research projects administered under the direction of the CEC by a competitively selected contractor, the University of California’s California Institute for Energy and the Environment, from 2003-2014

Disruption risk analysis of the overhead power lines in Portugal

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGThe growing increase in frequency and intensity of extreme weather events (EWEs) has a wide impact on energy systems and consumers, as energy transmission infrastructures - overhead power lines (OPL). The main objective of this work is to present the methodology of risk analysis of the EWEs on OPL in Portugal. The level of risk associated with each of the identified events is classified according to the probability of occurrence and consequences, in a risk matrix, and through the cause-and-effect analysis. It is concluded that, in Portugal, the extreme wind – corresponding to level 11 of the Beaufort Wind Force Scale, that is, values equal to or higher than 105.1 km h- 1 (29.22 m s-1) – is the main factor that provoked the OPL disruption, between 28% and 40% of analyzed events associated with windstorms. Considering the occurrence of compound events - wind and rain - the probability of damage to OPL is between 21% and 30%; for wind and ice, it is 3%–5%. EWEs represent a serious risk for electrical systems, and it is necessary to develop effective solutions to minimize the associated impacts, such as the modification and upgrade of the current design and engineering standards, and electrical network monitoring.Fundação para a Ciência e a Tecnologia | Ref. UID/GEO/50019/2019Fundação para a Ciência e a Tecnologia | Ref. PTDC/CTAMET/29233/2017Fundação para a Ciência e a Tecnologia | Ref. LISBOA-01-0145-FEDER-029233Fundação para a Ciência e a Tecnologia | Ref. NORTE-01-0145- FEDER-029233Fundação para a Ciência e a Tecnologia | Ref. UIDB/04033/2020Fundação para a Ciência e a Tecnologia | Ref. 2021.04927.BDXunta de Galicia | Ref. ED431C 2021/4

POWER DISTRIBUTION SYSTEM RELIABILITY AND RESILIENCY AGAINST EXTREME EVENTS

The objective of a power system is to provide electricity to its customers as economically as possible with an acceptable level of reliability while safeguarding the environment. Power system reliability has well-established quantitative metrics, regulatory standards, compliance incentives and jurisdictions of responsibilities. The increase in occurrence of extreme events like hurricane/tornadoes, floods, wildfires, storms, cyber-attacks etc. which are not considered in routine reliability evaluation has raised concern over the potential economic losses due to prolonged and large-scale power outages, and the overall sustainability and adaptability of power systems. This concern has motivated the utility planners, operators, and policy makers to acknowledge the importance of system resiliency against such events. However, power system resiliency evaluation is comparatively new, and lacks widely accepted standards, assessment methods and metrics. The thesis presents comparative review and analysis of power system resilience models, methodologies, and metrics in present literature and utility applications. It presents studies on two very different types of extreme events, (i) man-made and (ii) natural disaster, and analyzes their impacts on the resiliency of a distribution system. It draws conclusions on assessing and improving power system resiliency based on the impact of the extreme event, response from the distribution system, and effectiveness of the mitigating measures to tackle the extreme event. The advancement in technologies has seen an increasing integration of cyber and physical layer of the distribution system. The distribution system operators avails from the symbiotic relation of the cyber-physical layer, but the interdependency has also been its Achilles heel. The evolving infrastructure is being exposed to increase in cyber-attacks. It is of paramount importance to address the aforementioned issue by developing holistic approaches to comprehensibly upgrade the distribution system preventing huge financial loss and societal repercussions. The thesis models a type of cyber-attack using false data injection and evaluates its impact on the distribution system. It does so by developing a resilience assessment methodology accompanied by quantitative metrics. It also performs reliability evaluation to present the underlying principle and differences between reliability and resiliency. The thesis also introduces new indices to demonstrate the effectiveness of a bad-data detection strategy against such cyber-attacks. Extreme events like hurricane/tornadoes, floods, wildfires, storm, cyber-attack etc. are responsible for catastrophic damage to critical infrastructure and huge financial loss. Power distribution system is an important critical infrastructure driving the socio-economic growth of the country. High winds are one of the most common form of extreme events that are responsible for outages due to failure of poles, equipment damage etc. The thesis models effective extreme wind events with the help of fragility curves, and presents an analysis of their impacts on the distribution system. It also presents infrastructural and operational resiliency enhancement strategies and quantifies the effectiveness of the strategy with the metrics developed. It also demonstrates the dependency of resiliency of distribution system on the structural strength of transmission lines and presents measures to ensure the independency of the distribution system. The thesis presents effective resilience assessment methodology that can be valuable for distribution system utility planners, and operators to plan and ensure a resilient distribution system

Electric System Vulnerabilities: a State of the Art of Defense Technologies

Vulnerability of the European electrical infrastructure appears to be growing due to several factors: - demand is always growing, and, although this growth may be forecast, it cannot be anytime easily faced; - transactions increase, following electrical system liberalisation, and this involves operating the whole infrastructure closer to the system capacity and security limits; - an increased control systems complexity, required for secure system operation, may in turn raise system vulnerability, due both to accidental faults and malicious attacks; - critical infrastructures, and the electrical system primarily, are well known to be a privileged target in warfare, as well as terrorist attacks. In recent years, both Europe and America have experienced a significant number of huge blackouts, whose frequency and impact looks progressively growing. These events had common roots in the fact that current risk assessment methodologies and current system controls appear to be no longer adequate. Beyond the growing complexity of the electrical system as a whole, two main reasons can be listed: - system analysis procedures based on these methodologies did not identify security threats emerging from failures of critical physical components; - on-line controls were not able to avoid system collapse. This report provides a state-of-the-art of the technology on both regards: - as far as risk assessment methodologies are concerned, an overview of the conceptual power system reliability framework is provided, and the current N-1 principle for risk assessment in power systems is introduced, together with off-the-shelf enforcement methodologies, like optimal power flow. Emerging methodologies for dynamic security assessment are also discussed. The power system reliability approach is compared with the global approach to dependability introduced by computer scientists, and the conceptual clashes pointed out. Ways ahead to conciliate both views are outlined. - concerning power system controls, the report overviews the existing defense plans, making specific reference to the current Italian situation. The two major recent blackout events in the American North East and Italy are analysed, and the drawbacks of the existing arrangements and the installed control systems are discussed. Emerging technologies, such as phasor measurement units and wide area protection are introduced. Their likely impact on the existing control room is discussed. Finally, potential cyber vulnerabilities of the new control systems are introduced, the role of communication standards in that context is discussed, and an overview of the current state of the art is presented.JRC.G.6-Sensors, radar technologies and cybersecurit

Security of the Europena Electricity Systems: Conceptualizing the ssessment Criteria and Core Indicators

The electricity systems have a central role to play in the transition towards a low carbon economy and integration of renewable energy sources in the European Union. However, the European electricity networks face a diverse set of existing and new risks that can hamper the energy security of member countries. This paper aims to qualitatively and quantitatively assess these risks given the changing operating framework of the industry characterised by market liberalization and network interconnectedness among the EU members. Within this context, we primarily focus on the risks from exceptional events and threats to the European electricity systems. An ex-ante risk assessment matrix is proposed to gauge the network risks and take prevention measures against them. Such assessment can be a useful approach for policymakers and practitioners amidst the existing ex-post quality of supply performance standards and indicators. Our analysis suggests that economic risks pose the most serious and challenging risks to the evolving European electricity system

Asset management strategies for power electronic converters in transmission networks: Application to HVdc and FACTS devices

The urgency for an increased capacity boost bounded by enhanced reliability and sustainability through operating cost reduction has become the major objective of electric utilities worldwide. Power electronics have contributed to this goal for decades by providing additional flexibility and controllability to the power systems. Among power electronic based assets, high-voltage dc (HVdc) transmission systems and flexible ac transmission systems (FACTS) controllers have played a substantial role on sustainable grid infrastructure. Recent advancements in power semiconductor devices, in particular in voltage source converter based technology, have facilitated the widespread application of HVdc systems and FACTS devices in transmission networks. Converters with larger power ratings and higher number of switches have been increasingly deployed for bulk power transfer and large scale renewable integration—increasing the need of managing power converter assets optimally and in an efficient way. To this end, this paper reviews the state-of-the-art of asset management strategies in the power industry and indicates the research challenges associated with the management of high power converter assets. Emphasis is made on the following aspects: condition monitoring, maintenance policies, and ageing and failure mechanisms. Within this context, the use of a physics-of-failure based assessment for the life-cycle management of power converter assets is introduced and discussed

Resilience assessment and planning in power distribution systems:Past and future considerations

Over the past decade, extreme weather events have significantly increased worldwide, leading to widespread power outages and blackouts. As these threats continue to challenge power distribution systems, the importance of mitigating the impacts of extreme weather events has become paramount. Consequently, resilience has become crucial for designing and operating power distribution systems. This work comprehensively explores the current landscape of resilience evaluation and metrics within the power distribution system domain, reviewing existing methods and identifying key attributes that define effective resilience metrics. The challenges encountered during the formulation, development, and calculation of these metrics are also addressed. Additionally, this review acknowledges the intricate interdependencies between power distribution systems and critical infrastructures, including information and communication technology, transportation, water distribution, and natural gas networks. It is important to understand these interdependencies and their impact on power distribution system resilience. Moreover, this work provides an in-depth analysis of existing research on planning solutions to enhance distribution system resilience and support power distribution system operators and planners in developing effective mitigation strategies. These strategies are crucial for minimizing the adverse impacts of extreme weather events and fostering overall resilience within power distribution systems.Comment: 27 pages, 7 figures, submitted for review to Renewable and Sustainable Energy Review