Showing papers on "Blackout published in 2020"

A Review of the Measures to Enhance Power Systems Resilience

Abstract: Rare and extreme climate events may result in wide power outages or blackouts. The concept of power system resilience has been introduced for focusing on high-impact and low-probability (HILP) events such as a hurricane, heavy snow, and floods. Power system resilience is the ability of a system to reduce the likelihood of blackout or wide power outages due to HILP events. Indeed, in a resilient power system, as the severity of HILP events increases, the rate (but not the amount) of unserved loads diminishes. Suitable measures for managing power system resilience can be classified into three categories in terms of time, known as “resilience-based planning,” “resilience-based response,” and “resilience-based restoration.” The most widely used approaches, methods, and techniques in each of these categories, as well as the future trends for improving the power system resilience are reviewed in this article. The challenges of resilience in power systems with high penetration of renewable energy sources are also discussed in each of these categories.

Attacks on smart grid: power supply interruption and malicious power generation

Abstract: Electric power supply is an essential component for several sectors including manufacturing, healthcare, building management, water distribution, and transportation systems. Hence, any interruption in electric power is likely to have an undesirable impact on the overall operation of any residential or commercial ecosystem. The serious impacts of power supply interruption attacks have been realized in the recent cyber incidents such as the Ukraine power blackout. It is also evident from recent incidents that both network and process vulnerabilities are crucial for an adversary to cause an adverse impact on the operation. This paper reports an investigation into power supply interruption and malicious power generation attacks focusing on process and network vulnerabilities. The investigation was conducted in two steps: First, a vulnerability assessment was conducted on a fully operational electric power testbed. Next, the vulnerabilities discovered were exploited to perform different types of power supply interruption attacks and malicious power generation attacks. The attacks were executed using control code modification and SMA, a PV converter manufacturer, portal manipulation. The attacks reported here are useful for researchers and smart-grid operators to design and develop effective protection, detection, and response mechanisms.

Emergence of Scale-Free Blackout Sizes in Power Grids

Abstract: We model power grids as graphs with heavy-tailed sinks, which represent demand from cities, and study cascading failures on such graphs. Our analysis links the scale-free nature of blackout sizes to the scale-free nature of city sizes, contrasting previous studies suggesting that this nature is governed by self-organized criticality. Our results are based on a new mathematical framework combining the physics of power flow with rare event analysis for heavy-tailed distributions, and are validated using various synthetic networks and the German transmission grid.

Availability Assessment Based Case-Sensitive Power System Restoration Strategy

Abstract: Increasingly frequent severe weather events in recent years threaten the security of power systems and result in major power outages throughout the world. The development of reasonable power system restoration (PSR) solutions is therefore urgently needed to speed up the recovery of the power supply while at the same time steering clear of vulnerable and risky equipment. This paper aims to develop a case-sensitive PSR model for power transmission systems that can adjust restoration solutions according to the evaluated availability of outage equipment in specific blackout scenarios and weather conditions. A novel PSR model that integrates the startup of generating units, formulation of the restoration network, renewable energy sources, and availability assessment of devices is proposed. A reformulated model is also proposed to relieve the computational burden of complex PSR problems. The availability of outage equipment is comprehensively assessed based on historical operating records, fault diagnosis results, and weather conditions. The assessed availability results are sensitive to the characteristics of real blackout cases and will support system operators generate case-sensitive PSR solutions while mitigating the vulnerable equipment. The feasibility and effectiveness of the proposed PSR model and its reformulations are verified through case studies.

Pattern Analysis of Topological Attacks in Cyber-Physical Power Systems Considering Cascading Outages

Abstract: Modern cyber-physical power systems are vulnerable to cyber attacks. Given that cyber and physical networks are coupled tightly, attacks in the cyber layer can penetrate the physical layer, causing the outage of transmission lines and other physical equipment, thus changing the topology of the grid. In some extreme scenarios, the topological change will disrupt the emergency response of the grid, eventually causing cascading outages along with a blackout. Therefore, as the defender, the operator of a cyber-physical power system should identify critical cyber attacks. In this paper, patterns of sequential cyber topological attacks are analyzed. Firstly, a coordinated attack process is established, including mechanism and probability analysis considering the different timescales. Secondly, the concept of patterns is defined as minimal attack sequences aimed at causing blackouts. Furthermore, the representativeness of patterns is illustrated, which can significantly reduce the storage of risky attack sequences. Thirdly, to address the problem that the identification of patterns is computationally intensive, a search strategy that selects the next attack target dynamically and increases the search depth gradually is proposed to avoid unnecessary search trials. Lastly, tests are carried out on the IEEE 39-node system using the AC power flow model, which validates the representativeness of patterns and the performance of the proposed search strategy.

Decision tree analysis to identify harmful contingencies and estimate blackout indices for predicting system vulnerability

Abstract: Cascading failure is the main mechanism for progressing large blackouts in power systems. Following an initial event, it is challenging to predict whether there is a potential for starting cascading failure. In fact, the potential of an event for starting a cascading failure depends on many factors such as network structure, system operating point and nature of the event. In this paper, based on the application of decision tree, a new approach is proposed for identifying harmful line outages with the potential of starting and propagating cascading failures. For this purpose, associated with each trajectory of the cascading failure, a blackout index is defined that determines the potential of the initial event for triggering cascading failures towards power system blackout. In order to estimate the blackout indices associated with a line outage, a three stages harmful estimator decision tree (HEDT) is proposed. The proposed HEDT works based on the online operating data provided by a wide area monitoring system (WAMS). The New England 39-bus test system is utilized to show the worthiness of the proposed algorithm.

Stochastic Cascading Failure Model With Uncertain Generation Using Unscented Transform

Abstract: This paper proposes a novel stochastic cascading failure (CF) model with full ac power flow using the unscented transform (UT) for power girds vulnerability analysis. The quasi-steady state (QSS) model is built upon previous dc power flow model by incorporating several enhancements. Our analysis shows that dc power flow does not provide an accurate estimation of the flow process under highly variable generation thus may underestimate the severity of the cascades. The incorporation of full ac power flow constraints allows us to access voltage profiles dynamics during CF in order to simulate voltage-related failures in the grid. The under-voltage load shedding relays are modeled along with a stochastic time-inverse overload relay to accurately simulate the protective system response. In addition, more realistic assumptions are considered in the modeling of wind power penetration using geographical information of grid topology and wind potential map for a given geographical area. The accuracy of the estimated flow process based on UT method is examined under different operating conditions in a 500-bus synthetic network. The proposed model is benchmarked against the historical blackout data and widely used models in the literature showing similar statistical patterns of blackout size.

Integration of renewable distributed generation with storage and demand side load management in rural islanded microgrid

Abstract: The integration between distributed generations, storage, and load for islanded microgrids located in rural areas of developing countries offer serious challenges. The rural microgrid, catering the energy needs of rural communities, has no access to modern information and communication amenities like internet, communication architectures, and backup power. The lack of information and communication technologies (ICT) and backup power sources in rural microgrid lead to uncontrolled load consumption and inefficient storage dispatch resulting in system-wide outages. This paper proposes a novel approach to overcome challenges such as affordability and accessibility. A proactive load controlling and prioritized smart load curtailment is proposed in real time using local system parameters and human activities. The objective is to reduce blackouts and ensure maximum load supply without using conventional backup sources, computational forecasting, scheduling tools, and sophisticated communication architectures. The fuzzy logic controller is proposed to proactively decide for a percentage of load to be curtailed. Human Activities Tracking System (HATS) for smart load curtailment is used for balanced and efficient integration between the distributed generation, storage, and load. Four system parameters, storage drain time, state of charge (SoC), running load, and solar irradiations, are used as input to the fuzzy controller. HATS controller is used to smartly prioritize the load curtailment based on human occupancy in different buildings. Human activities are monitored using pyroelectric sensors installed at the entrance of different buildings. The performance of the system has been assessed while comparing the proposed methodology, the SoC controlling method (SCM). While using the proposed methodology, the blackout was drastically reduced to 96 to 100%. State of charge depletion rate was considerably less than conventional methods.

Surface catalysis effects on mitigation of radio frequency blackout in orbital reentry

Abstract: Radio frequency (RF) blackout during atmospheric reentry leads to the cutoff of communication with ground stations and/or data-relay satellites. This causes significant problems during reentry, and thus, mitigation methods have been in high demand. In this study, we numerically demonstrate a novel method for mitigating the RF blackout using surface catalysis effects. Plasma flow behavior and electromagnetic wave propagation around a reentry vehicle were investigated in detail. The approach couples computational fluid dynamics and a frequency-dependent finite-difference time-domain method. The computations were performed with a massive parallelization technique using a large computer. The computed results were compared for cases imposing low and full catalysis conditions on a surface boundary. The investigation revealed that the surface catalysis effects reduce the RF blackout. Atomic species, dissociated across a shock wave formed in front of the vehicle, were recombined on the vehicle surface through surface catalysis. These molecules, flowing into a wake region at the vehicle's rear, caused recombinations of electrons, originally generated in the shock layer. Therefore, a decrease in electrons was observed in the wake region and a wake path, which allows the propagation of electromagnetic waves, was formed. This complicated behavior of the molecules and electrons, induced by the surface catalysis, resulted in mitigation of the RF blackout.

A Test of the Theory of Planned Behavior in the Prediction of Alcohol-Induced Blackout Intention and Frequency

Abstract: Background This study examined the theory of planned behavior (TPB) as an explanatory model for alcohol-induced blackouts among college students. Blackouts are periods of time wherein individuals continue to function and engage in their social environment but do not remember it as a result of consuming large quantities of alcohol. Social cognitive factors posited within TPB, such as perceived norms and personal attitudes toward alcohol consumption, are reliable predictors of alcohol use and related problems. However, research to date has not examined these theoretical antecedents as predictors of alcohol-induced blackout. Methods College students with a history of blackout (N = 384) completed a baseline survey, and a subsample (N = 120) completed a 1-month follow-up survey. Negative binomial mediation models were used to evaluate intentions to blackout as a mediator of the norms, attitudes, and self-efficacy to avoid blackout-blackout frequency association at baseline and 1-month follow-up. Results Norms, attitudes, and self-efficacy to avoid blackout all significantly predicted blackout intentions at baseline, which in turn predicted more frequent blackouts both at baseline and at 1-month follow-up. Notably, blackout attitudes demonstrated both direct and indirect associations with blackout frequency. Conclusions Prospective analyses provided partial support for the TPB, with only attitudes and intentions demonstrating prospective associations with actual blackout frequency. Given the particularly strong association between blackout attitudes and frequency of blackouts, attitudes may represent an important and novel target for prevention and intervention efforts.

Mitigation strategy against cascading failures considering vulnerable transmission line in power grid

Abstract: In this paper, we devise a mitigation strategy against cascades considering the vulnerable transmission lines. Firstly, we convert the complex grid into its dual graph, and then rank the vulnerability of transmission lines by the modified theory of structural holes named M-Burt method. Finally, the mitigation strategy is used to upgrade the transmission line capacities utilizing the identification results in the system evaluation to bring about the mitigation. The simulations on the IEEE-39 bus system and the IEEE 118 bus system show that the M-Burt method can identify the vulnerable transmission lines effectively and the mitigation strategy by the M-Burt method can reduce the power blackout risks drastically.

Posting Post-Blackout: A Qualitative Examination of the Positive and Negative Valence of Tweets Posted after "Blackout" Drinking.

Abstract: Alcohol-induced memory loss (i.e., blackout) is a consequence of drinking that is both common and associated with additional negative outcomes. The goal of the present study was to use publicly ava...

Intentions and motives to experience alcohol-induced blackout among young adults in college.

Abstract: Blackouts are typically considered a negative consequence of alcohol use. Yet some college students report consuming alcohol with the intention of blacking out. This study examined intentions and motives for blackout drinking among young adults in college. College students with a past-year history of blackout (N = 350, 56% female, 73% White) completed an anonymous online survey. Descriptive statistics were used to examine the incidence of blackout intentions, and individuals who did and did not report future blackout intentions were then compared on drinking patterns, depressive symptoms, social norms, and outcome expectancies. Overall, 135 participants (39%) reported consuming alcohol in the past 30 days with the intention of losing memory of the night's events, and 107 (31%) reported blackout intentions in the next 30 days. When asked (via open text box) to indicate their motives for past blackout intentions, the majority of participants provided responses that fit with coping, social, or enhancement drinking motives. A larger proportion of men than women reported blackout intentions. As a group, those reporting future blackout intentions reported heavier, more frequent, and more problematic drinking, as well as more symptoms of depression and more positive (but not negative) outcome expectancies. A substantial subset of college students reporting a blackout in the past year also endorsed intentions to experience a blackout in the next 30 days. Given strong associations between intentions and subsequent behavior, interventions targeting blackout styles of drinking are warranted. The extent to which "blackout" drinking motives differ from traditional drinking motives is unclear. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

An Improved Label Propagation Algorithm-Based Method to Develop Sectionalizing Strategies for Parallel Power System Restoration

Abstract: The first task of parallel power system restoration is to sectionalize the blackout system into multiple subsystems. This paper applies the complex network community discovery theory into this sectionalizing problem and proposes an improved label propagation algorithm-based sectionalizing method considering the system topology and operation before blackouts. Firstly, each blackstart (BS) unit bus is marked with a different subsystem label. A label propagation matrix is calculated based on the active power of branches before the blackout. Then, to avoid the label oscillation, a novel label impact strategy considering the influence of the bus label itself is developed to improve the label propagation matrix. The buses' labels propagate to neighboring buses as the improved label propagation matrix until they do not change. The initial sectionalizing strategy is obtained through classifying the buses with the same label in the same subsystem. Finally, the sectionalizing constraints are used to evaluate the feasibility of the initial strategy. For the initial strategy that does not satisfy the constraints, a refining method to minimize the absolute value of active power exchange among subsystems is proposed to determine the final sectionalizing strategy based on it. Case studies on IEEE 39-bus and IEEE 118-bus test systems verify the effectiveness of the proposed method. The results indicate that the proposed method has advantages in creating strongly connected subsystems.

Communication blackouts in power outages: Findings from scenario exercises in Germany and France

Abstract: Although infrequent, power outages can cause major disruption and incur huge costs. The increasing demand for electricity, more extreme weather events and the possibility of cyber-attack are increasing the risk of blackouts. This paper reports using scenario planning and role-playing exercises with German and French university students to investigate people's possible reactions and their expectations of government during a hypothetical 3-day blackout. The scenario is designed to explore how society would cope with a power failure over successive time periods. The aim is provide information to emergency managers and policy makers about community needs and people's likely behavior in future blackouts.

Analytical Approaches on Optimal Placement of STATCOM Under Contingency Occasions

Abstract: Electrical power utilities nowadays are facing various challenges with emerging technologies that leads to increase in demand on electrical power. Due to the aging grid infrastructure, existing power transmission networks are forced to operate at near critical point which could cause tripping in transmission lines and potentially lead to cascading outages and blackout. During this point, voltage at some buses drop below the lower voltage limit and the system power loss is significantly high. Constructing new power system networks or expanding existing networks is a must to accommodate the impact of ever-increasing demand. However, this consumes a lot of time and money. This can be alleviated by integrating Flexible Alternating Current Transmission System (FACTS) devices in the existing transmission system. In order to ensure investment feasibility, the location of FACTS devices in the network is essential. In this study, several analytical approaches using loss sensitivity factor (LSF), real power performance indicator (PI), voltage profile index (VPI) and power loss index (PLI) is carried out to examine the optimal location of Static Synchronous Compensator (STATCOM) in the power system. The proposed analytical approaches were examined using the IEEE 14 bus and IEEE 30 bus benchmark test systems in DigSILENT PowerFactory 18.

Advanced algorithm to detect stealthy cyber attacks on automatic generation control in smart grid

Abstract: One of the basic requirements of today's sophisticated world is the availability of electrical energy, and neglect of this matter may have irreparable damages such as an extensive blackout. The problems which were introduced about the traditional power grid, and also, the growing advances in smart technologies make the traditional power grid go towards smart power grid. Although widespread utilisation of telecommunication networks in smart power grid enhances the efficiency of the system, it will create a critical platform for cyber attacks and penetration into the system. Automatic generation control (AGC) is a fundamental control system in the power grid, and it is responsible for controlling the frequency of the grid. An attack on the data transmitted through the telecommunications link from the sensors to the AGC will cause frequency deviation, resulting in disconnection of the load, generators and ultimately global blackout. In this study, by using a Kalman filter and a proposed detector, a solution has been presented to detect the attack before it can affect the system. Contrary to existing methods, this method is able to detect attacks that are stealthy from the area control error signal and X2-detector. Simulations confirm the effectiveness of this method. (Less)

Demonstration of Man in the Middle Attack on a Feeder Power Factor Correction Unit

Abstract: Cyber security of distribution power systems is of an increasing and pressing importance due to the fast modernisation of current systems. Cyber attacks on distribution power systems may aim to operate the system inefficiently, steal private smart meter data or cause intentional false tripping of few or all feeders. In this paper, a Man in The Middle (MiTM) attack on a power factor correction unit is implemented and demonstrated to overload a distribution feeder and cause an intentional false tripping of the entire feeder causing regional blackout. Experimental implementation of the attack is carried out in a laboratory-scale setup using commercial power equipment under different loading conditions to demonstrate the effectiveness of this attack.

Support of Frequency Stability in Electrical Power System at Voltage 400 kV in Syria

Abstract: Based on the importance of electrical connection to maintain the frequency stability of the eight Arab energy systems (Egypt, Iraq, Jordan, Lebanon, Libya, Palestine, Syria and Turkey). The article will present a series of simulations in the Syrian network for 2018 using the program(PSS/E) and using this program to compare data with the results of real situations by applying several cases of a power blackout that occurred in the Syrian energy system (recorded by frequency when they occur). This study demonstrates the importance of electrical interconnection in frequency stability, which reports the most important technical and economic benefits achieved for the electrical network stability in general and frequency stability by the (EIJLLPST) project. As for the applied study, it has been through a number of simulations on the Syrian network for the year 2018 using the (PSS/E), and rely on this program after comparing the calculated results with the results of real situations, through the application of several cases of blackout occurred in the Syrian network, where the experiences of this research focused on the importance of the spinning reserve, electrical interconnection and the ion of electrical loads using underfrequency relay to maintain the stability of the electrical grid frequency in Syria, to avoid falling into undesirable values of frequency.

Robust power balancing scheme for the grid-forming microgrid

Abstract: Control over the voltage and the frequency instabilities in a grid-forming microgrid due to the power mismatch conditions become the point of concern. Therefore, the study implements a self-tuned proportional–integral integrated active power–voltage drooping and reactive power–frequency boosting control strategy for the precise power sharing among the distributed generators. Furthermore, to handle the power deficit scenarios and protect the system from the blackout, a system independent and priority-based adaptive three-stage load shedding strategy is proposed. The sensitivity of the strategy depends on the system inertia and is computed according to the varying absolute rate-of-change-of-frequency. The strategy incorporates the operation of a hybrid storage system comprised of battery and supercapacitor present in the microgrid, to provide a reliable power supply to the customers for a considerable time rather than a sudden load shedding. The effectiveness of the proposed strategies is investigated on a modified IEEE 13-bus system. The study is simulated in the time domain, on the podium of MATLAB 2015b.

Decreased resilience in power grids under dynamically induced vulnerabilities

Abstract: In this paper, a methodology inspired on bond and site percolation methods is applied to the estimation of the resilience against failures in power grids. Our approach includes vulnerability measures with both dynamical and structural foundations as an attempt to find more insights about the relationships between topology and dynamics in the second-order Kuramoto model on complex networks. As test cases for numerical simulations, we use the real-world topology of the Colombian power transmission system, as well as randomly generated networks with spatial embedding. It is observed that, by focusing the attacks on those dynamical vulnerabilities, the power grid becomes, in general, more prone to reach a state of total blackout, which in the case of node removal procedures it is conditioned by the homogeneity of power distribution in the network.