Showing papers on "Blackout published in 2021"

An open-source extendable model and corrective measure assessment of the 2021 texas power outage

Abstract: Unprecedented winter storms that hit across Texas in February 2021 have caused at least 69 deaths and 4.5 million customer interruptions due to the wide-ranging generation capacity outage and record-breaking electricity demand. While much remains to be investigated on what, how, and why such wide-spread power outages occurred across Texas, it is imperative for the broader macro energy community to develop insights for policy making based on a coherent electric grid model and data set. In this paper, we collaboratively release an open-source extendable model that is synthetic but nevertheless provides a realistic representation of the actual energy grid, accompanied by open-source cross-domain data sets. This simplified synthetic model is calibrated to the best of our knowledge based on published data resources. Building upon this open-source synthetic grid model, researchers could quantitatively assess the impact of various policies on mitigating the impact of such extreme events. As an example, in this paper we critically assess several corrective measures that could have mitigated the blackout under such extreme weather conditions. We uncover the regional disparity of load shedding. The analysis also quantifies the sensitivity of several corrective measures with respect to mitigating the severity of the power outage, as measured in Energy-not-Served (ENS). This approach and methodology are generalizable for other regions experiencing significant energy portfolio transitions.

Compound Climate and Infrastructure Events: How Electrical Grid Failure Alters Heat Wave Risk.

Abstract: The potential for critical infrastructure failures during extreme weather events is rising. Major electrical grid failure or "blackout" events in the United States, those with a duration of at least 1 h and impacting 50,000 or more utility customers, increased by more than 60% over the most recent 5 year reporting period. When such blackout events coincide in time with heat wave conditions, population exposures to extreme heat both outside and within buildings can reach dangerously high levels as mechanical air conditioning systems become inoperable. Here, we combine the Weather Research and Forecasting regional climate model with an advanced building energy model to simulate building-interior temperatures in response to concurrent heat wave and blackout conditions for more than 2.8 million residents across Atlanta, Georgia; Detroit, Michigan; and Phoenix, Arizona. Study results find simulated compound heat wave and grid failure events of recent intensity and duration to expose between 68 and 100% of the urban population to an elevated risk of heat exhaustion and/or heat stroke.

Climate change and infrastructure risk: Indoor heat exposure during a concurrent heat wave and blackout event in Phoenix, Arizona

Abstract: Concurrent with a rapid rise in temperatures within US cities, the frequency of regional electric grid system failures is also rising in recent decades, resulting in a growing number of blackouts during periods of extreme heat. As mechanical air conditioning is a primary adaptive technology for managing rising temperatures in cities, we examine in this paper the impact of a prolonged blackout on heat exposure in residential structures during heat wave conditions, when air conditioning is most critical to human health. Our approach combines a regional climate modeling system with a building energy model to simulate how a concurrent heat wave and grid failure event impacts residential building-interior temperatures across Phoenix. Our results find a substantial increase in heat exposure across residential buildings in response to the loss of electrical power and mechanical cooling systems, with such an event potentially exposing more than one million residents to hazardous levels of heat. We further find the installation of cool roofing to measurably lower the risk of extreme heat exposure for residents of single-story structures.

Power Grids as Complex Networks: Resilience and Reliability Analysis

Abstract: Power grids are cyber-physical systems and can be modelled as network systems where individual units (generators, busbars and loads) are interconnected through physical and cyber links. Network components (nodes/edges) may undergo intentional and/or random failures. In catastrophic cases, a failure initiating from a small set of these components can quickly propagate through the whole network, leading to a cascade of failures that might force a deep whole-grid blackout. Often network components have different vitality and protecting some is more critical than others. This manuscript aims to provide a focused overview of modelling power grids as complex networks and their resilience and reliability analysis. We also perform a critical review of vitality metrics and their precision in power grid resilience analysis. The review is accompanied by some simulations on benchmark and real power grids to show the applicability of these concepts in studying resilience.

Black-Start and Service Restoration in Resilient Distribution Systems with Dynamic Microgrids

Abstract: The resilience of distribution systems has been challenged by power outages caused by natural disasters, which calls for novel solutions to system restoration. However, the existing black-start (BS) techniques are mainly developed at the transmission level. This problem can be resolved by adopting dynamic microgrids (MGs), i.e., MGs with dynamic and adjustable boundaries nested in the distribution systems. This paper proposes a restoration procedure that adopts self-organizing inverters as BS units and achieves distribution system restoration in the context of dynamic MGs. The proposed restoration procedure is structured as a two-stage approach, and designed to restore a complete blackout distribution system to the state where the system is ready for seamless main grid reconnection. A framework of dynamic MGs operation is developed which improves the self-healing capability of off-grid distribution systems with automatic sectionalization and flexible reconfiguration. A sequence of actions during restoration is defined, along with distributed controllers designed with considerations of practical operating challenges. The proposed restoration procedure is validated on a 34-bus system using real-time hardware-in-the-loop simulation.

Research on Current-Limiting Control Strategy Suitable for Ground Faults in AC Microgrid

Abstract: On August 9, 2019, a blackout event with significant impacts occurred in the British power grid (BPG) The technical report submitted by the BPG points out that the accident originated from multiple independent and concurrent events, resulting in a sudden power shortage, which exceeded the fortification requirements of the relevant standards This incident has led us to reflect on some of the technical bottlenecks that exist in the high-proportion renewable energy system, such as frequency oscillations, security defense of large power grid, current-limiting, and so on Based on this background, this article studies a strong current-limiting control system suitable for ground faults in ac microgrid, which can limit the fault current to less than twice the rated current so that the distributed generators can go through multiple faults ride-through without offline operation Meanwhile, this control system does not need to switch the reference inductance current between normal and faults and can realize the smaller current harmonics and lower asymmetry amplitudes in the two states Simulation and experiment show that the method proposed in this article can adapt to a variety of ground faults

False Data Injection Attacks Against Synchronization Systems in Microgrids

Abstract: Synchronization systems play a vital role in the day-to-day operation of power systems and their restoration after cascading failures. Hence, their resilience to cyberattacks is imperative. In this paper, we demonstrate that a well-planned false data injection attack against the synchronization system of a generator is capable of causing tripping subsequently leading to instability and blackout. We present an analytical framework behind the design and implementation of the proposed cyberattack. Moreover, we derive and discuss the conditions for which a cyberattack interfering with a synchronizing signal can be successful. Effective physical mitigation strategies are then proposed to improve the cyber-resilience of synchronization systems. The proposed cyberattack model and mitigation strategies are verified for a microgrid test system using an OPAL-RT real-time simulator.

Describing the impact of the COVID-19 pandemic on alcohol-induced blackout tweets.

Abstract: Introduction and aims COVID-19, considered a pandemic by the World Health Organization, overwhelmed hospitals in the USA. In parallel to the growing pandemic, alcohol sales grew in the USA, with people stockpiling alcohol. Alcohol-induced blackouts are one particularly concerning consequence of heavy drinking, and the extent to which blackout prevalence may change in the context of a pandemic is unknown. The purpose of the current study is to describe the prevalence of publicly available tweets in the USA referencing alcohol-induced blackouts prior to and during the COVID-19 outbreak. Design and methods We used Crimson Hexagon's ForSight tool to access all original English tweets written in the USA that referenced alcohol-related blackouts in 2019 and 2020. Using infoveillance methods, we tracked changes in the number and proportion of tweets about blackouts. Results More alcohol-related blackout tweets were written between 13 March and 24 April in 2020 than 2019. In addition, a greater proportion of all tweets referenced blackouts in 2020 than in 2019. In the period prior to the 'stay at home' orders (January to mid-March), the proportion of blackout tweets were higher in 2020 than 2019. Discussion and conclusion Our findings demonstrate that references to high-risk drinking persist during the pandemic despite restrictions on large social gatherings. Given that the internet is a common source of information for COVID-19, the frequent posting about blackouts during this period might normalise the behaviour. This is concerning because alcohol use increases susceptibility to COVID-19, and alcohol-related mortality can further tax hospital resources.

Load Shedding in Microgrids with Consideration of Voltage Quality Improvement

Abstract: Microgrids have become more and more popular their usefulness as a renewable energy resource has been recognized. The core ability and promise of microgrids is addressing the environmental concerns due to climate change that have been growing during recent years. The innovation of microgrids is that they are designed to operate either in island mode or interconnected with the main grid system. However, when the microgrid operates in islanded mode, faults may occur which can cause system collapse or even blackout. Load curtailment schemes can be utilized to decrease the quantity of associated load to a level that can be securely supported by accessible generation in isolated mode. The main goal of this research is to evaluate the optimal amount of shedding power considering sustainable power sources, with the help of primary and secondary adjustments of the generator to restore the frequency to the allowed range. Particle Swarm Optimization algorithm is applied in this paper to determine the distributed shedding power on each demand load bus which can improve the voltage quality of the isolated microgrid system. The effectiveness of the proposed method is demonstrated through the simulation of IEEE 16- bus microgrid.

Grid Support with Wind Turbines: The Case of the 2019 Blackout in Flensburg

Abstract: The work presented in this paper aims to show how modern wind turbines can help to control the frequency in a small grid which suffers from large power imbalances. It is shown for an exemplary situation, which occurred in Flensburg’s distribution grid in 2019: a major blackout, which occurred after almost two hours in islanding operation, affecting almost the entire distribution grid, which supplies approximately 55,000 households and businesses. For the analysis, a wind turbine model and a grid support controller developed at the Wind Energy Technology Institute are combined with real measurements from the day of the blackout to generate a fictional yet realistic case study for such an islanding situation. For this case study, it is assumed that wind turbines with grid support functionalities are connected to the medium voltage distribution grid of the city. It is shown to what extent wind turbines can help to operate the grid by providing grid frequency support in two ways: By supplying synthetic inertia only, where the wind turbines can help to limit the rate of change of frequency in the islanded grid directly after losing the connection to the central European grid. In combination with the primary frequency control capabilities of the wind turbines (WTs), the disconnection of one gen set in the local power station might have been avoided. Furthermore, wind turbines with primary frequency control capabilities could have restored the grid frequency to 50 Hz shortly after the islanding situation even if the aforementioned gen-set was lost. This would have allowed connecting a backup medium voltage line to the central European grid and thereby avoiding the blackout.

Resilience-Oriented Dispatch of Microgrids Considering Grid Interruptions

Abstract: By providing a reliable and economical supply of energy, microgrids (MGs) may play a pivotal role in the case of large grid disruptions. However, the resilience benefits of microgrids in terms of outage survivability that often lead to economic paybacks are not well investigated in the existing literature. To address this concern, this paper optimizes and simulates a grid-connected MG placed at a hospital consisting of a photovoltaic (PV) module and an energy storage unit that can adequately prevent a prolonged blackout. The impact of net energy metering (NEM) and diesel generator (DG) has further been examined for this hybrid system. Four different cases have been optimized and results show that the PV and battery work in tandem, both with and without considering the existing DG and NEM and meets all critical load demand during a grid outage. The findings also indicate that the proposed approach yields significant economic benefits for two cases relative to business as usual case.

Distribution of blackouts in the power grid and the Motter and Lai model.

Abstract: Carreras, Dobson, and colleagues have studied empirical data on the sizes of the blackouts in real grids and modeled them with computer simulations using the direct current approximation. They have found that the resulting blackout sizes are distributed as a power law and suggested that this is because the grids are driven to the self-organized critical state. In contrast, more recent studies found that the distribution of cascades is bimodal resulting in either a very small blackout or a very large blackout, engulfing a finite fraction of the system. Here we reconcile the two approaches and investigate how the distribution of the blackouts changes with model parameters, including the tolerance criteria and the dynamic rules of failure of the overloaded lines during the cascade. In addition, we study the same problem for the Motter and Lai model and find similar results, suggesting that the physical laws of flow on the network are not as important as network topology, overload conditions, and dynamic rules of failure.

Multi-Stage Dynamic Transmission Network Expansion Planning Using LSHADE-SPACMA

Abstract: This paper introduces a multi-stage dynamic transmission network expansion planning (MSDTNEP) model considering the N-1 reliability constraint. The integrated planning problem of N-1 security and transmission expansion planning is essential because a single line outage could be a triggering event to rolling blackouts. Two suggested scenarios were developed to obtain the optimal configuration of the Egyptian West Delta Network’s realistic transmission (WDN) to meet the demand of the potential load growth and ensure the system reliability up to the year 2040. The size of a blackout, based on the amount of expected energy not supplied, was calculated to evaluate both scenarios. The load forecasting (up to 2040) was obtained based on an adaptive neuro-fuzzy inference system because it gives excellent results compared to conventional methods. The linear population size reduction—Success-History-based Differential Evolution with semi-parameter adaptation (LSHADE-SPA) hybrid—covariance matrix adaptation evolution strategy (CMA-ES) algorithm (LSHADE-SPACMA)—is applied to solve the problem. The semi-adaptive nature of LSHADE-SPACMA and the hybridization between LSHADE and CMA-ES are able to solve complex optimization problems. The performance of LSHADE-SPACMA in solving the problem is compared to other well-established methods using three testing systems to validate its superiority. Then, the MSDTNEP of the Egyptian West Delta Network is presented, and the numerical results of the two scenarios are compared to obtain an economic plan and avoid a partial or total blackout.

Brownout Based Blackout Avoidance Strategies in Smart Grids

Abstract: Power shortage is a serious issue especially in developing nations. Such power deficits are traditionally handled through rolling blackouts. Today, smart grids provide the opportunity of avoiding complete blackouts, converting them to brownouts which allow selective provisioning of power to support essential loads while curtailing supply to less critical loads. We formulate the power distribution problem as an ILP and show that solution strategies such as conventional dynamic programming (DP) impose substantial overheads. So, we propose the Streamlined DP-based Priority level Allocator (SDPA) which utilizes the discrete nature of power demands of each subarea and generates the overall optimal solution far quicker by focusing on a lower number of non-dominating partial DP-solutions. SDPA is found to be about 9 to 33 times faster than DP and applicable to real-time power distribution in moderate sized grids. However, even SDPA may fail in very large grids. So, a faster approach namely, Proportionally Balanced Priority level Allocator (PBPA), has been designed and implemented. Experimental results show that although solutions provided by PBPA could be less effective by upto 12% compared to optimal dynamic programming based schemes, being about 4 orders of magnitude faster, it can be deployed for real time allocations of power.

Trajectories of alcohol-induced blackouts in adolescence: early risk factors and alcohol use disorder outcomes in early adulthood

Abstract: Background and aims: Experience of alcohol-induced memory blackouts in adolescence may be an important risk factor for later harms. This longitudinal study (i) modelled trajectories of alcohol-related blackouts throughout adolescence, (ii) explored early-adolescent predictors of blackout trajectories and (iii) examined the association between blackout trajectories and alcohol use disorder (AUD) symptoms. Design: Longitudinal study in which data from six annual surveys of a longitudinal cohort of Australian adolescents were used to model latent class growth trajectories of blackouts, adjusting for alcohol consumption frequency and typical quantity. Regression models were used to determine whether parent, child and peer factors at baseline (mean age = 12.9) predicted profiles of blackout trajectory membership and whether blackout trajectories predicted meeting criteria for AUD in early adulthood (mean age = 19.8). Setting and participants: Australian adolescents (n = 1821; mean age = 13.9-18.8 years). Measurements: Alcohol-related blackouts, alcohol consumption frequency, typical consumption quantity and DSM-5 AUD in early adulthood were all self-reported. Findings: We identified a three-class solution: delayed alcohol initiation, rare blackouts (n = 701; 38.5%); early initiation, rare blackouts (n = 869; 47.7%); and early initiation, increasing blackouts (n = 251; 13.8%). Female sex was associated with increased risk of early initiation, increasing blackouts relative to delayed initiation, rare blackouts [relative risk ratio (RRR) = 3.90; 99.5% confidence interval (CI) = 1.96, 7.76] and relative to early initiation, rare blackouts (RRR = 2.89; 99.5% CI = 1.42, 5.87). Early initiation, rare blackouts [odds ratio (OR) = 1.96; 99.5% CI = 1.17, 3.29] and early initiation, increasing blackouts (OR = 4.93; 99.5% CI = 2.32, 10.48) were each associated with increased odds of meeting criteria for AUD in early adulthood relative to delayed initiation, rare blackouts. Early initiation, increasing blackouts was associated with increased odds of meeting criteria for AUD in early adulthood relative to early initiation, rare blackouts (OR = 2.51; 99.5% CI = 1.18, 5.38). Conclusions: Females in Australia appear to be at higher risk of adolescent alcohol-related blackouts independent of alcohol consumption levels and age of initiation. Alcohol-related blackouts may be associated with later alcohol use disorder.

State-of-the-Art Reactor Consequence Analyses Project: Uncertainty Analyses for Station Blackout Scenarios

Abstract: This paper provides an overview of the U.S. Nuclear Regulatory Commission’s (NRC’s) project to develop a technical report summarizing the most important insights from its three State-of-the-Art Rea...

Cascading Failure Pattern Identification in Power Systems Based on Sequential Pattern Mining

Abstract: Cascading failure simulation data contain many fault chains (FCs), which can present cascading failure propagation paths. In cascading failure process, some component outages play dominating roles in propagation, indicating the common characteristics among different FCs. The commonness is embodied as combinations of components which are vulnerable to trip and cause serious blackout consequences. In addition, a component outage will increase the outage probability of relevant components and induce dependent outage in subsequent stage. Such relevance between two components can be called component outage causality. A combination of sequential component outages with outage causalities, which exists in different FCs and leads to system load loss, can be regarded as a cascading failure pattern (CFP). Statistical characteristics of FCs indicate that CFPs are variously distributed in different FCs, can present propagation paths and cause different impacts on system blackouts. This paper proposes a cascading failure pattern (CFP) identification method based on sequential pattern mining approach. The proposed method focuses on mining CFPs from massive FCs, quantifies the influence of CFP on system blackout and identifies the critical ones. The proposed method is verified with FCs data on IEEE 39-bus and 118-bus test systems.

A Combinatorial Safety Analysis of Cruise Ship Diesel–Electric Propulsion Plant Blackout

Abstract: Diesel–Electric Propulsion (DEP) has been widely used for the propulsion of various ship types including cruise ships. Considering the potential consequences of blackouts, especially on cruise ships, it is essential to design and operate the ships’ power plants for avoiding and preventing such events. This study aims at implementing a comprehensive safety analysis for a cruise ship Diesel–Electric Propulsion (DEP) plant focusing on blackout events. The Combinatorial Approach to Safety Analysis (CASA) method is used to develop Fault Trees considering the blackout as the top event, and subsequently estimate the blackout frequency as well as implement importance analysis. The derived results demonstrate that the overall blackout frequency is close to corresponding values reported in the pertinent literature as well as estimations based on available accident investigations. This study deduces that the blackout frequency depends on the number of operating Diesel Generator (DG) sets, the DG set’s loading profile, the amount of electrical load that can be tripped during overload conditions and the plant operation phase. In addition, failures of the engine auxiliary systems and the fast-electrical load reduction functions, as well as the power generation control components, are identified as important. This study demonstrates the applicability of the CASA method to complex marine systems and reveals the parameters influencing the investigated system blackout frequency, thus providing better insights for these systems’ safety analysis and enhancement.