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Electric vehicles (EVs) are being introduced in Rwanda and becoming attractive for different reasons. For instance, these types of vehicles can help decrease air pollution and noise emissions. In addition, it presents an alternative to combustion engines, given the increased price of fuel resources in Rwanda and around the world. This paper presents a tool tailored to optimize the design of an electrical charging station serving small-sized electric vehicles, utilizing the algorithm to assist in sizing stand-alone mopped charging stations. The developed tool is based on the toolbox EventSim from MathWorks, which permits the combination of the simulation of discrete events (such as the arrival of customers at the station) with continuous states (such as the simulation of the charging process). The required PV power was estimated by utilizing solar resources, for the location, from renewables. Ninja. The number of customers arriving at the existing oil station is normalized to estimate the energy requirements of the mopped fleet. A Poisson distribution was proposed to model the battery discharge upon arrival, and different related parameters were evaluated through a sensitivity analysis to identify their effects on the performance of photovoltaic charging station. For the testing values, the station parameters were changed by ±25% to determine the impact of key design parameters on station performance, as well as other satisfaction measures such as average waiting time and average queue length. With a 25% increase in photovoltaic panels, the blackout period decreases by 2.12%, while a 25% decrease in photovoltaic panels causes an increase of 2.18% in the blackout period. Utilizing the energy management system (EMS), the waiting time was reduced by 8%.

The Southern Cameroon Interconnected Network (SIG) is depicted as a large-scale power system that has shown significant instability due to a series of blackouts in recent years. These blackouts are primarily attributed to major disruptions in transmission lines and energy deficits between supply and demand. The imbalance between power supply and demand necessitates the grid to operate near its stability limits, increasing the risk of blackouts. The necessity of investigating the dynamics of SIG behavior in response to observed contingency situations serves as the primary motivation for this study. To achieve this objective, the SIG was modeled using saturated generators with ZIP static loads. Through Newton-Raphson based power flow calculations, voltage magnitude profiles of the grid were obtained for each generation scenario. An N-1 contingency consisting of a standard Newton-based continuation power flow (CPF) analysis has identified line 5–6 as the most frequent worst case of line outage. Additionally, a short-term transient analysis was conducted under three-phase short-circuit, line outage and generator outage scenarios. In the event of a short-circuit, the Mangombe-225 bus experienced the most significant impact. Concerning line outages, line 1–5 had the most adverse effect on the grid's frequency stability. However, generation outages had a lesser impact on frequency stability compared to other disturbances. Lastly, modal analysis revealed that the grid exhibited weak stability with a critical mode identified at a frequency of 4.0267 Hz, exceeding typical values. This underscores the necessity of damping the grid oscillations for enhanced stability.

Power systems are the most complicated networks that play a crucial role in daily lifestyles. To operate such systems in a stable condition, several control and protection strategies are required. Despite preventative measures, power systems still experience issues and breakdowns like power outages. However, severe and unanticipated conditions might cause damage to the entire system and causes blackout. In this article we studied the analysis of the significant blackouts and cascading failures that have been happened in Pakistan in last few years. The authors proposed a new infrastructure for Pakistan energy sector by introducing advanced energy storage system and cutting edge technology like Vehicle-to-Grid (V2G) technology that make the existing power system robust against these phenomena. The advanced energy storage systems include like solid- state batteries that play a vital role to balance supply and demand, while V2G enables electric vehicles to contribute to grid stability. The potential of these technologies is helpful to improve the grid stability and facilitate a sustainable energy transition. The role of various electric companies in Pakistan power infrastructure has also been discussed after an occurrence of such unplanned events in power system. It has been noted that the main cause of power outages is fluctuation in frequency and voltage collapse. Finally, various solutions have been proposed to overcome these problems and make sure the reliability and stability of power grid against blackout phenomena.

Piped drinking water supplies are exposed to a range of threats. Changing hazard situations arise from climate change, digitisation, and changing conditions in the power supply, among other things. Risk and crisis management adapted to the hazard situation can increase the resilience of the piped drinking water supply. Analogous to the risk management system, this article describes a methodology that ranges from hazard analysis with the prioritisation of 57 individual hazards to vulnerability assessment with the help of balance sheet structure models (BSM) and the planning and implementation of measures to increase the resilience of the piped drinking water supply in a targeted manner. The work steps mentioned build on each other and were tested using the case study of a water supply company in Saxony (Germany). As a result, priority hazards are identified, the remaining supply periods and replacement and emergency water requirements are determined as part of the vulnerability assessment, and finally, planning principles for increasing resilience are documented. The methodology focuses primarily on practicable application by water supply companies.

Recent history demonstrates that threat has no borders, though risk does, due to national and regional differences in vulnerabilities and exposure landscapes. The difference between well and poorly managed threat is striking. Inequalities in preparing for threats as a function of their type are still apparent. Compared to more concerning electromagnetic interference threats, the impact of geomagnetic disturbance (GMD) on power grid operation is not well studied. The need for detailed research of GMD negative impacts is expected to broaden awareness. The amplitude of geomagnetically induced currents (GICs) is treated as a uniform measure of danger that can be processed by various stakeholders. Hence, methods for increasing the accuracy of GIC representation are presented in this paper. A low-entropy signal is defined and it is shown that the feature of low signal entropy can be used for increasing the accuracy of the measurement equipment. At the end, a full-system view of GMD impact on power grid operation is given.

An undeclared war has been going on in Ukraine for more than one year. Defeated at the front, Russia resorted to massive shelling of energy facilities with the aim of leaving Ukrainians wit­hout electricity and heat during the winter. As reported, since October 10, the Russians have fired more than a thousand missiles and drones at Ukrainian energy facilities. The shelling on November 23, 2022 led to a system crash — a blackout occurred. For the first time in the history of Ukraine, all of the country’s nuclear power units were shut down. In conditions of lack of light and non-wor­king refrige­rating chambers, the storage conditions of thermolabile immunobiological drugs became a new test for the medical community and patients. As you know, immunobiological drugs, which are widely used in the treatment of various rheumatological disea­ses, require strict storage conditions in the temperature range from +2 to +8 °С. Under blackout conditions, it is difficult for Ukrainian patients to maintain optimal storage conditions for these drugs. The analysis of the studies showed that the majority of patients do not comply with the requirements for the storage of thermolabile drugs, even with the constant presence of light and electricity. Experts indicate that more and more thermolabile drugs are becoming available, and in most cases, these medications are dispensed to ambulatory patients. More thermolabile drugs are becoming avai­lable, and in most cases, these medications are dispensed to ambulatory patients. However, there is no regulation once medications are dispensed to patients and little is known with regard to what happens during transport and home sto­rage. Previous studies suggest that these drugs are improperly stored. Future studies should focus on clinical consequences and possible solutions. It is recommended for Ukrainians to follow the rules and conditions of sto­rage of heat-labile medicinal products during blackouts/emergency and stabilization blackouts.

A grid blackout is an intractable problem with serious economic consequences in many developing countries. Although it has been proven that microgrids (MGs) are capable of solving this problem, the uncertainties regarding when and for how long blackouts occur lead to extreme difficulties in the design and operation of the related MGs. This paper addresses the optimal design problem of the MGs considering the uncertainties of the blackout starting time and duration utilizing the kernel density estimator method. Additionally, uncertainties in solar irradiance and ambient temperature are also considered. For that, chance-constrained optimization is employed to design residential and industrial PV-based MGs. The proposed approach aims to minimize the expected value of the levelized cost of energy (LCOE), where the restriction of the annual total loss of power supply (TLPS) is addressed as a chance constraint. The results show that blackout uncertainties have a considerable effect on calculating the size of the MG’s components, especially the battery bank size. Additionally, it is proven that considering the uncertainties of the input parameters leads to an accurate estimation for the LCOE and increases the MG reliability level.

Cascading effects in the power grid involve an uncontrolled, successive failure of elements. The root cause of such failures is the combined occurrence of multiple, statistically rare events that may result in a blackout. With increasing digitalisation, power systems are vulnerable to emergent cyber threats. Furthermore, such threats are not statistically limited and can simultaneously occur at multiple locations. In the absence of real-world attack information, however, it is imperative to investigate if and how cyber attacks can cause power system cascading failures. Hence, in this work we present a fundamental analysis of the connection between the cascading failure mechanism and cyber security. We hypothesise and demonstrate how cyber attacks on power grids may cause cascading failures and a blackout. To do so, we perform a systematic survey of major historic blackouts caused by physical disturbances, and examine the cascading failure mechanism. Subsequently, we identify critical cyber-physical factors that can activate and influence it. We then infer and discuss how cyber attack vectors can enable these factors to cause and accelerate cascading failures. A synthetic case-study and software-based simulation results prove our hypothesis. This analysis enables future research into cyber resilience of power grids.

The objective of this paper is to enhance the frequency resilience and wind penetration level of a low inertia power system by utilising frequency responsive Thyristor Controlled Series Capacitor (TCSC). In recent years, wind power integration has become prolific in numerous power grids around the world. As such, Synchronous Generators (SGs) are being substituted from the generation mix. Unlike conventional synchronous generators, variable speed Wind Turbine Generators (WTGs) generally do not participate in system frequency control without additional control strategy. When subjected to prolific wind generation and interconnection import from an adjacent grid, number of online SGs in a grid can be scant. During such a situation, a large contingency in the power importing zone may overload an AC interconnection. Consequently, the interconnection could trip due to loss of synchronism. It eventually may cause a system-wide blackout. In addition, due to the risk of network separation, non-synchronous wind penetration level is kept restricted in many power systems. To overcome these challenges, this paper proposes a frequency responsive TCSC model to increase interconnection transfer capability by reducing the line reactance. To this end, for determining optimal TCSC parameters, a strategy is outlined. Furthermore, a generalised expression is developed to find the maximum wind penetration level while maintaining the frequency response adequacy. The developed techniques are applied to a low inertia test system. Simulation results reveal that the risk of blackout is averted, and the maximum wind penetration level is significantly increased after deploying the frequency responsive TCSC.

In this study, a resident questionnaire survey was conducted for three reinforced-concrete high-rise condominium buildings in Sapporo. All three were subjected to the 2018 Hokkaido Eastern Iburi Earthquake. Resident experiences of shaking and damage due to the earthquake, the seismic measures taken before and after the earthquake, and conditions during the long-term blackout were evaluated by the survey. Resident anxiety and their difficulty in taking actions due to the shaking were relatively small, because the ground motions input to the buildings were not very large. The long-term power outage due to the earthquake had a great impact on the occupants. Particularly, the inability to use elevators caused a great inconvenience to the residents of higher floors, making it difficult for them to leave their dwelling units. Each of the three buildings was equipped with an emergency power supply; however, differences in the operation methods of these supplies affected the convenience of the occupants during the power outage. The inconvenience and anxiety caused by the shaking and the power outage left a strong impression on the residents. This may have resulted in motivation to make further earthquake preparations, such as stockpiling of flashlights, lanterns, food, and water, after the complex disaster.

Today’s modern society depends on a number of infrastructures to operate. Failures in these systems cause significant economic impacts and can also endanger people’s lives and health. Due to the high importance of these infrastructures, they’ve received increasing attention in recent years and are referred to as critical infrastructure. Critical infrastructure in the energy sector is considered to be one of the most important infrastructure networks significantly contributing to ensuring the functional continuity of the society. Its importance is also perceived in terms of interconnections and correlations with other critical infrastructure sectors as well as in terms of electricity interconnectivity in Europe, as in the interconnected European system the effects are spreading across the systems of all single country transmission system operators very quickly. For these reasons, the European Union considers this sector to be strategic and of European importance. The aim of this article is to clarify the primary causes of the disruption of large-scale electricity supply and their impact on the functioning of society, focusing on the vulnerability of urbanized large settlements – urban agglomerations – in the event of long-lasting blackout disturbances. It contains a presentation of the importance of electricity for society, the definition, and the analysis of the causes of disruption to large-scale electricity supply continuity, consequences of a large-scale blackout on community functioning and its basic functions, and current knowledge on the vulnerability of large urban agglomerations to long-term disruption of electricity supply and possible solutions.

The Mumbai region in India experienced a massive outage on October 12, 2020, due to cascade failure. The event taught some serious lessons to the grid operators and highlighted the need for energy security and reliability. In this incident, the cascade tripping of the external transmission network resulted in an unexpected island containing Mumbai city isolating it from the rest of Indian power grid. Although the Mumbai islanding scheme was operational, it failed to survive due to high rate of change of frequency (ROCOF). Globally, such blackouts occur due to low probability, high impact events. Major blackouts are caused by a set of triggering events that are usually preceded by some incidents that weaken the power system. Further, the failure of important security mechanisms and protections can compound the effect of disturbances. In view of this, the paper focuses on the consequences of cascading events that led to several blackouts in history. This paper analyses the October 12, 2020, Mumbai power grid failure by recreating various scenarios that resulted in the blackout through dynamic modelling on the PSS/E platform. The results were validated using data collected from phasor measurement units (PMUs) and SCADA. In this article various challenges faced during unfolding of the event are presented. Lessons learnt such as appropriate settings and tuning were identified to ensure the survival of islanding scheme. Assessment of Mumbai power system’s transfer capability is done to facilitate the optimal mix of imported and embedded generation.

Today's modern society depends on a number of infrastructures to operate. Failures in these systems cause significant economic impacts and can also endanger the lives and health of the population. The high importance of these infrastructures has led them to increasing attention in recent years and are referred to as critical infrastructure. Critical infrastructure in the energy sector is considered to be one of the most important infrastructure networks significantly entering into ensuring the functional continuity of the society. Its importance is also perceived in terms of interconnections and correlations with other critical infrastructure sectors as well as in terms of electricity interconnectivity in Europe, as in the interconnected European system the effects are spreading across systems of all single country transmission system operators very quickly. For these reasons, the European Union considers this sector to be strategic and of European importance. The aim of the article is to clarify the primary causes of disruption of large-scale electricity supply and their impact on the functioning of society, focusing on the vulnerability of urbanized large settlements - urban agglomerations in the event of long-lasting blackout disturbances. It contains a presentation of the importance of electricity for society, definition and analysis of the causes of disruption of large-scale electricity supply continuity, consequences of large-scale blackout on community functioning and its basic functions and current knowledge on vulnerability of large urban agglomerations to long-term disruption of electricity supply and possible solutions.

The massive blackout that occurred in August 2003 left over 50 million people in the northeastern and midwestern parts of the United States without electricity and caused billions of dollars in economic losses. This event highlighted the importance of sustainable and resilient energy infrastructure. Our study examines the impact of this blackout on the sustainability of financial markets by analyzing the liquidity and information asymmetry of U.S. stocks listed on major exchanges. Our results show that the blackout had a negative impact on the financial market’s liquidity, as evidenced by a significant widening of bid–ask spreads and a decrease in the market quality index. We also find an increase in information asymmetry during the blackout period, as measured by higher realized spreads. Furthermore, our study reveals that the blackout had a border impact on global financial markets and the negative effect on liquidity persisted even after two weeks.

Mira Kubasińska (1944–2005) was one of the most characteristic figures in female pop that appeared in the big beat era on the Polish scene. She was recognised because of her outstanding vocal abilities, natural gift for shaping lyrics, exceptional expression and an extraordinary sense of rhythm. Her artistic creation, completely devoid of stylisation, posing and mannerisms, fully reflected her temperament, philosophy of life and disregard for opportunistic attitudes. The peak of Kubasińska’s stage activity falls within the period of 1966–1973 and encompasses cooperation with bands led by her husband Tadeusz Nalepa – Blackout and Breakout. During that period, she released two solo albums (Mira and Ogień) and climbed to the top. Starting in the mid–1970s, the singer’s career suffered a serious blow, which was a result of Tadeusz Nalepa’s stylistic turn towards blues as well as the end of their marriage and a resulting personal crisis. This artist has not been the subject of scientific scrutiny as of yet, so this text aims to fill this gap. Apart from the biographical thread, the author attempts to analyse the singer’s oeuvre and describe the evolution of her artistic image. The text also presents a broader context of the circumstances on the Polish popular music scene in the 1960s and 1970s.

The necessary precautions should be taken in order to prevent service interruption during the maintenance and repairing of electricity networks. Among these measures, emergencies that may occur in the network should be foreseen, hazard scenarios should be created, and solutions should be developed. If these are not done, a blackout, which first follows the local regions and eventually results in the collapse of the national electrical network, may take place. In this study, the national blackout of Turkey that occurred on 31 March 2015 is examined. The information about Turkey’s electrical infrastructure and its energy policies was provided, as well as the reliability assessment criteria for power systems and examples of significant blackouts that occurred worldwide. The direct relation between line voltage and system frequency was provided with mathematical derivation by using real data taken from a local industrial zone. Then, a case study is presented to demonstrate this direct relation. The causes, development process, and consequences of the blackout are discussed in detail, and some recommendations are offered to increase the security of the electrical infrastructure and to prevent future occurrences while ensuring the sustainability of the system.

Grid resiliency is defined as the ability to prepare for and adapt to changing conditions and withstand and recover rapidly from disruptions. Following large-scale disruptions of the power grid such as a complete blackout, parallel power system restoration accelerates the recovery process by allowing for simultaneous restoration in each island through network partitioning, thus enhancing grid resiliency. However, existing network partitioning strategies have not sufficiently considered variable renewable resources yet, and may not be flexible or computationally efficient to accommodate additional requirements from the evolving bulk power grid. To bridge these gaps, this study proposes a propagation-based optimization approach for power grid network partitioning. The requirements of blackstart resources, power balancing, synchrocheck relays for ties lines, and increased ramp rate requirements due to variable renewable resources are modeled in the constraints. Through propagation on the physical connectivity of grid assets, the network partitioning issue is formulated as a mixed integer linear programming (MILP) problem. The linearity ensures highly computational performance and optimality of the solutions from the proposed approach to identify the cutset edge possibilities for bulk power grid applications. Graph reduction strategies are proposed to further improve the computational performance for online or nearly online applications. Case studies based on two IEEE benchmark systems show that the proposed MILP model is able to determine the optimal cutset for network partitioning in approximately 0.28 seconds, and the proposed network reduction strategy is able to further improve the computational performance by approximately 9%.

In this paper, we propose an AC power flow based cascading failure model that explicitly considers external weather conditions, extreme temperatures in particular, and evaluates the impact of extreme temperature on the initiation and propagation of cascading blackouts. Based on this model, resilience analysis of the power system is performed with extreme temperatures. Specifically, the changes of load and dynamic line rating are modeled due to temperature disturbance. The probabilities for transmission line and generator outages are evaluated, and the timing for each type of events is calculated to decide the actual event sequence. It should be emphasized that the correlated events, in the advent of external temperature changes, could contribute to voltage instability. Besides, we model undervoltage load shedding and operator re-dispatch as control strategies for preventing the propagation of cascading failures. The effectiveness of the proposed model is verified by simulation results on the RTS-96 3-area system. It is found that temperature disturbances can lead to correlated load change and line/generator tripping, which will greatly increase the risk of cascading and voltage instability. Critical temperature change, critical area with temperature disturbance, the identification of most vulnerable buses, and the comparison of different control strategies are also investigated.

When an entire power system blacks out, the system operator uses a self-starting generator to initiate the recovery procedure that starts the priority generator using a transmission line. Because most self-starting generators are pumped storage generators, they are located at a distance from the priority generators. This results in long transmission lines that can cause overvoltage during the recovery process through the line charging effect. Herein, the above issue is resolved by replacing the self-starting generator with an energy storage system (ESS) to reduce the possibility of overvoltage generation. The transmission line is shortened by moving the ESS closer to the priority generator, thus utilizing its flexible installation feature: an ESS has no location constraints for installation. In addition, this study determines an effective location for the ESS to minimize the reactive power requirements: moving the ESS closer to the priority generator reduces the required reactive power. Thus, the capacity of the power conditioning system can be reduced, which is advantageous in terms of cost-effectiveness.

During a blackout, after the post-disaster collapse of an electric power system (EPS), units of thermal power plants should switch-over to the house load operation mode (PPW). However, regarding the dynamics of a post-disaster blackout process, many units can be in forced outage Therefore, restart of these units from the start-up sources with a self-start capability is necessary. The Transmission Network Code in force imposes periodic tests and system tests for such sources. Any system test must be preceded and followed by simulation investigations in which the possibilities: (1) to bring voltage to the started-up power plant by a starting path and (2) to activate the highest-power auxiliaries (PW) of the unit being started-up are evaluated. In the paper, chosen results of simulative investigations of the transient phenomena in the starting path from the hydroelectric power plant of Włocławek (HPP Włocławek) to the thermal power plant of P˛atnów (TPP P˛atnów), related to the system test conducted in September 2017 have been presented.

Many citizens of European countries may soon experience a long and extensive blackout. The lack of predictability in the output of renewable energy sources, aggravating the problem of consistently matching supply with demand on electric grids, along with cyber-attacks or even worse unpredictable incidents in the electric grid are some factors that may mean a blackout is much more likely than in previous years. This paper covers the possibility of an extensive blackout in a country of the interconnected European electricity transmission system or, even worse, a blackout in a wide area of the European continent. The topic of this paper becomes even more important and timely given the energy crisis due to the war in Ukraine, which has made the possibility of a blackout in the winter of 2022–2023 high. First, the major European blackouts that occurred in the past 20 years are presented, examining their causes. On 8 January 2021, the European electricity grid was divided into two separate sections, with different frequencies; some additional scenarios are considered which, if they had happened, could have led to blackouts in some European countries or, even worse, a wide area of Europe. This work also examines how to avoid such an eventuality, as well as how European TSOs should react in case a blackout occurs. Focused on the fast and reliable supply of consumers after a blackout, a novel restoration strategy based on the A* Algorithm is presented. Its efficiency is validated in the IEEE-39 and IEEE-68 bus systems.

In February 2021, rolling blackouts in Texas during Winter Storm Uri demonstrated the vulnerability of the State’s electric grid managed by the Electric Reliability Council of Texas (ERCOT). This article examines the technical causes of the ERCOT blackouts, financial and human consequences, and policy changes that could prevent recurrences. ERCOT planned for a winter load peak far below actual electricity demand. Further electricity shortfalls were caused by generation plants with varied energy sources becoming unavailable—natural-gas fired, coal-fired, nuclear, wind, and solar. Prior blackouts during a 2011 period of cold weather had shown the need for better resource planning and plant weatherization, but advance preparation was inadequate. The system of compensating generators in ERCOT was market-based with a $9,000 per megawatt hour cap on wholesale electricity rates—a so-called “Energy-Only market.” This regulatory system did not provide adequate incentives for generation plants to be operational during extreme weather, nor did it ensure that natural gas suppliers could deliver fuel to generators. Texas is well-situated for a return to the cost-of-service regulatory model; the State Legislature should consider this policy option.

Breath-hold diving (freediving) is an underwater sport that is associated with elevated hydrostatic pressure, which has a compressive effect on the lungs that can lead to the development of pulmonary edema. Pulmonary edema reduces oxygen uptake and thereby the recovery from the hypoxia developed during freediving, and increases the risk of hypoxic syncope. We aimed to examine the efficacy of SpO2, via pulse-oximetry, as a tool to detect pulmonary edema by comparing it to lung ultrasound B-line measurements after deep diving. SpO2 and B-lines were collected in 40 freedivers participating in an international deep freediving competition. SpO2 was measured within 17 ± 6 min and lung B-lines using ultrasound within 44 ± 15 min after surfacing. A specific symptoms questionnaire was used during SpO2 measurements. We found a negative correlation between B-line score and minimum SpO2 (rs = −0.491; p = 0.002) and mean SpO2 (rs = −0.335; p = 0.046). B-line scores were positively correlated with depth (rs = 0.408; p = 0.013), confirming that extra-vascular lung water is increased with deeper dives. Compared to dives that were asymptomatic, symptomatic dives had a 27% greater B-line score, and both a lower mean and minimum SpO2 (all p < 0.05). Indeed, a minimum SpO2 ≤ 95% after a deep dive has a positive predictive value of 29% and a negative predictive value of 100% regarding symptoms. We concluded that elevated B-line scores are associated with reduced SpO2 after dives, suggesting that SpO2 via pulse oximetry could be a useful screening tool to detect increased extra-vascular lung water. The practical application is not to diagnose pulmonary edema based on SpO2 – as pulse oximetry is inexact – rather, to utilize it as a tool to determine which divers require further evaluation before returning to deep freediving.

ObjectiveTo explore patients’ long-term experiences with drinking alcohol after Roux-n-Y gastric bypass (RYGB) for conceptualizing what may indicate problematic drinking behavior after bariatric surgery.Study DesignThree-center, observational study.Patients546 adult patients undergoing RYGB in the period 2003-2009 in Norway.Main Outcome MeasuresSelf-reported data on drinking behavior and experiences related to alcohol collected 10-15 years after surgery.ResultsOut of the 959 patients undergoing RYGB in the period, 29 were diseased and 546 participated in this follow-up study (58.7%). Focusing on suspicious changes in drinking behavior, 8.8% reported drinking more, 11.5% consumed alcohol at least twice a week, and 10.6% consumed at a minimum of 6 units of alcohol at a frequency of at least once monthly. The nature of hangovers had changed for about a third of the patients, with 21.6% reporting these to feel weaker or absent. Repeated alcoholic blackouts were reported by 11.9%. A subgroup of the patients were categorized as displaying presumed problematic drinking behavior(PPDB). Among the PPDB-men there was a significant association to having had a fall last year (6 (100.0%) PPDB-patients vs. 30 (29.7%) non-PPDB, p

This paper presents two schemes of UFLS to keep the system frequency within safe limits. GA-based scheme is introduced as an offline method to get the proper amount of shed load achieving the minimum and steady state frequency within permissible limits. Due to the probability of generation variation and generating units outage during shedding process, ANN-based scheme is presented as an online method to adjust the proper amount of load shedding at any amount of power deficit. Multi scenarios of contingences are carried out on offline mode using GA optimization technique to collect the training patterns for ANN. The ANN-based scheme can consider the generation variations during the load shedding process. Although using this scheme may shed more loads, it maintains the frequency to be within permissible limits at various disturbance scenarios particularly at the absence of secondary control. An analytic system frequency response (SFR) model with no secondary control incorporating UFLS scheme is presented. The proposed method is compared with the classical adaptive method to prove its effectiveness. Results are presented in the form of time domain simulations via MATLAB/SIMULINK.

Northern electric grid of Italy was involved in a black start mock drill. This test took place on November 2016 in order to check the coordination and efficiency of all the operational staffs and the automatic regulators involved in the case of a real blackout scenario. This paper presents the results of a research carried out in collaboration with Terna Rete Italia (the Italian Transmission System Operator), in order to find strengths and weaknesses and eventually to upgrade the existing restoration plan. Starting from the measures coming from generating plants and substations bars, the model of frequency regulation system for both the participating hydro and thermal power plants is developed. This work gives the system operator an essential tool to understand many complex dynamics and phenomena occurred during the test. At the same time, a robust model simulating the system behavior with different grid configurations is presented: it gives the opportunity to enhance both the classical power system control theory and the black start practices.

The article is focused on the issue of blackouts in a water industry and the selection of a renewable energy source for a water treatment plant. In the case of power outage, it is necessary to constantly ensure the supply of a drinking water, if this requirement would not be met, it could cause of deterioration of hygiene and health of the population. To be able to convey drinking water during a blackout, it is mandatory to have a backup power supply. The state of the current water treatment plants in the Czech Republic is that they are using diesel generators as backup power supply, which causes air pollution. There are other options of power supply that can be used, such as renewable energy sources. By using a multi-criteria analysis method, renewable energy sources were analyzed for a water treatment plant in the selected region. Based on the results, it seems that the most suitable choice is a small hydro power plant at the entry points of water treatment plant. Other possibilities of renewable energy sources that may be suitable for a water treatment plant and the usage of a multi-criteria analysis method for a water treatment plant in other countries are also discussed.

The article concerns the energy security of a wastewater treatment process caused by unforeseen situations related to the risk of electrical power outages. In this case, renewable energy sources based on distributed generation power systems can solve this problem in each wastewater treatment plant. The article highlights e related challenges and proposes the direction of solutions in this regard based on Czech conditions. The first part of the paper deals with the consequences of long-term outage of wastewater treatment plants on the population and the environment. There are several solutions presented for blackout conditions, and model calculations are made based on data from a Czech wastewater treatment plant. Diesel engine-generators, biogas as a cogeneration source of heat and electricity, solar panels with storage systems and combined biogas and solar systems were considered as approaches to provide energy autonomy during a blackout in a wastewater treatment plant. Special attention was paid to a combination of CHP units with solar panels and batteries. The results were evaluated for three different locations for this combination. It was concluded that biogas combustion in the CHP unit was the most profitable option, allowing the production of electricity independently of the grid for its own consumption and possibly for other operations. The last part of the paper deals with the transition to island operation, which must occur during a blackout. This transition is more difficult for both solar panels and cogeneration units if they were to supply electricity to the grid before a blackout. The transition to energy island operation could be ensured by frequency relay and processor devices to control the circuit breaker. Then, to maintain island operation, it would be necessary to have an automatic load shedding/application system.

In recent years, the occurrence of cascading failures and blackouts arising from cyber intrusions in the underlying configuration of power systems has increasingly highlighted the need for effective power management that is able to handle this issue properly. Moreover, the growing use of renewable energy resources demonstrates their irrefutable comparative usefulness in various areas of the grid, especially during cascading failures. This paper aims to first identify and eventually protect the vulnerable areas of these systems by developing a hybrid structure-based microgrid against malicious cyber-attacks. First, a well-set model of system vulnerability indices is presented to indicate the generation unit to which the lines or buses are directly related. Indeed, we want to understand what percentage of the grid equipment, such as the lines, buses, and generators, are vulnerable to the outage of lines or generators arising from cyber-attacks. This can help us make timely decisions to deal with the reduction of the vulnerability indices in the best way possible. The fact is that employing sundry renewable resources in efficient areas of the grid can remarkably improve system vulnerability mitigation effectiveness. In this regard, this paper proposes an outstanding hybrid-energy framework of AC/DC microgrids made up of photovoltaic units, wind turbine units, tidal turbine units, and hydrogen-based fuel cell resources, all of which are in grid-connect mode via the main grid, with the aim to reduce the percentage of the system that is vulnerable. To clearly demonstrate the proposed solution’s effectiveness and ease of use in the framework, a cyber-attack of the false data injection (FDI) type is modeled and developed on the studied system to corrupt information (for instance, via settings on protective devices), leading to cascading failures or large-scale blackouts. Another key factor that can have a profound impact on the unerring vulnerability analysis concerns the uncertainty parameters that are modeled by the unscented transform (UT) in this study. From the results, it can be inferred that vulnerability percentage mitigation can be achieved by the proposed hybrid energy framework based on its effectiveness in the system against the modeled cyber-attacks.

The subject of this paper is the semantics of the colour black in anarchism. The author analyses the sociocultural and ontological aspects of the colour black as a symbol of anarchist criticism of power and the state. The anarchist black colour is counterposed to the white colour — a symbol of power in many cultures. The author shows that the idea of destruction, which the black colour of anarchy manifests, is correlated with the anthropological universals of visual experience. This idea is connected with the prototypical root of the colour black — the night, which is associated with chaos across many cultures. The protest semantics of the colour black is increasingly used in contemporary art activism. The author considers examples demonstrating that the colour black is used to criticise political representation and the anonymity of power. The primary focus is on the artistic practices of blackout (painting over/blocking out in black ink), which are interpreted in the context of the criticism of the political idea of transparency. In conclusion, the opacity of the black and white colours is compared. It is shown that the colour black can serve as a tool to create a radical semantic gap.

Abstract As the power control technology of wind farms develops, the output power of wind farms can be constant, which makes it possible for wind farms to participate in power system restoration. However, due to the uncertainty of wind energy, the actual output power can’t reach a constant dispatch power in all time intervals, resulting in uncertain power sags which may induce the frequency of the system being restored to go outside the security limits. Therefore, it is necessary to optimize the dispatch of wind farms participating in power system restoration. Considering that the probability distribution function (PDF) of transient power sags is hard to obtain, a robust optimization model is proposed in this paper, which can maximize the output power of wind farms participating in power system restoration. Simulation results demonstrate that the security constraints of the restored system can be kept within security limits when wind farm dispatch is optimized by the proposed method.

To facilitate recovery from hypoxia, many freedivers use a breathing method called “hook breathing” (HB) after diving, involving an interrupted exhale to build up intrapulmonary pressure. Some divers experience a delay in recovery of arterial oxygen saturation (SaO2) after diving, interpreted as symptoms of mild pulmonary edema, and facilitated recovery may be especially important in this group to avoid hypoxic “blackout.” We examined the influence of HB on recovery of SaO2 in freedivers with slow recovery (SR) and fast recovery (FR) of SaO2 after deep “free immersion” (FIM) apnea dives to 30 m depth. Twenty-two male freedivers, with a mean (SD) personal best in the discipline FIM of 57(26) m, performed two 30 m deep dives, one followed by HB and one using normal breathing (NB) during recovery, at different days and weighted order. SaO2 and heart rate (HR) were measured via pulse oximetry during recovery. The SR group (n = 5) had a faster SaO2 recovery using HB, while the FR group (n = 17) showed no difference between breathing techniques. At 105 s, the SR group reached a mean (SD) SaO2 of 95(5)% using HB, while using NB, their SaO2 was 87(5)% (p < 0.05), and 105–120 s after surfacing SaO2 was higher with HB (p < 0.05). In SR subjects, the average time needed to reach 95% SaO2 with HB was 60 s, while it was 120 s at NB (p < 0.05). HR was similar in the SR group, while it was initially elevated at HB in the FR group (p < 0.05). We conclude that HB efficiently increases SaO2 recovery in SR individuals, but not in the FR group. The proposed mechanism is that increased pulmonary pressure with HB will reverse any pulmonary edema and facilitate oxygen uptake in divers with delayed recovery.

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.

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.

In this article we review the method of representation an electrical power grid as a graph. Then we state a definition of structural vulnerability as the main feature of electric power grid reliability, which allows to evaluate the blackout probability. We have created the methodic of locating critical element (nodes) by using GIS-technologies and tested it on studied regions. As the result, we have located zones of high and low structural vulnerability. In addition, some priority areas for investigation with the help of the network model are given.

An effective application for hydrogen technologies at nuclear power plants is proposed, which improves the plant maneuverability during normal operation, and provides for in-house power supply during the plant blackout. The reliability of the NPP's emergency power supply was assessed probabilistically for the plant blackout conditions with the simultaneous use of an auxiliary full-time operating steam turbine and the emergency power supply system channels with diesel generators. The proposed system with an additional steam turbine makes it possible to use the reactor core decay heat for the reactor shutdown for 72 h. During the blackout at a plant with several units, the additional steam turbine power required for the unit cool down is maintained by additional steam generated by the combustion of hydrogen in oxygen. It has been shown that the proposed flowchart with an auxiliary full-time operating small-power steam turbine installed at the NPP, combined with an integrated hydrogen facility, improves the reliability of the NPP in-house power supply during blackout accidents.

Objective: To explore how a genetically-influenced characteristic (the level of response to alcohol [LR]), ethnicity, and sex relate to environmental and attitudinal characteristics (peer drinking [PEER], drinking to cope [COPE], and alcohol expectancies [EXPECT]) regarding future alcohol-related blackouts (ARBs). Methods: Structural equation models (SEMs) were used to evaluate how baseline variables related to ARB patterns in 462 college students over 55 weeks. Data were extracted from a longitudinal study of heavy drinking and its consequences at a U.S. university. Results: In the SEM analysis, female sex and Asian ethnicity directly predicted future ARBs (beta weights 0.10 and -0.11, respectively), while all other variables had indirect impacts on ARBs through alcohol quantities (beta weights ~ 0.23 for European American ethnicity and low LR, 0.21 for cannabis use and COPE, and 0.44 for PEER). Alcohol quantities then related to ARBs with beta = 0.44. The SEM explained 23% of the variance. Conclusion: These data may be useful in identifying college students who are more likely to experience future ARBs over a 1-year period. They enhance our understanding of whether the relationships of predictors to ARBs are direct or mediated through baseline drinking patterns, information that may be useful in prevention strategies for ARBs.

This paper aims at putting forward viewpoints regarding the use of stability technology to prevent and control cascading outages by examining recent blackout events. Based on the inquiry reports of the 2011 Southwest America blackout and the 2012 India power blackouts, event evolution features are first summarized from a stability perspective. Then a comparative analysis is conducted so as to propose suggestions of effective measures, either preventive or emergency, which could have avoided the blackouts. It is shown that applications of several mature technologies can create opportunities of preventing or interrupting the cascading development. These include offline dynamic simulation, online stability analysis and preventive control, real-time situational awareness and automatic emergency control. Further R & D directions are given to address the challenges of modern power systems as well. They cover system fault identification criterion of protection and control devices, verification of adaptability of control effect to system operating conditions, real-time operational management of emergency control measures and improvement of simulation accuracy.

Increasing demand for electricity and the modernization of power systems within competitive markets has induced power systems to operate close to their stability limits. Therefore, the continuous monitoring and control of power systems through voltage stability indices is urgently needed. This is the first-ever effort to examine more than 40 voltage stability indices based on their formulation, application, performance, and assessment measures. These indices are sorted based on a logical and chronological order considering the most recent indices to be applied worldwide. However, the generalizability of these indices in terms of multivariable objectives is limited. Despite its limitation, this study systematically reviews available indices in the literature within the past three decades to compile an integrated knowledge base with an up-to-date exposition. This is followed by a comparative analysis in terms of their similarity, functionality, applicability, formulation, merit, demerit, and overall performance. Also, a broad categorization of voltage stability indices is addressed. This study serves as an exhaustive roadmap of the issue and can be counted as a reference for planning and operation in the context of voltage stability for students, researchers, scholars, and practitioners.

This article discusses the issues related to a power unit of a thermal power plant start-up with the use of a hydropower plant. Hydropower plant can supply and will enable start-up of auxiliary equipment in a power unit of a thermal power plant. Due to high capacity of auxiliary drives, startup of auxiliaries in a thermal power plant after blackout (and boiler shutdown) is not possible from emergency energy sources in the power plant. In such a case an external electricity source with high capacity is required.

We investigate the ability of interference absorption control in thin magnetic films. This control is obtained by variation of external magnetic field and phase difference of counter propagating waves. Depending upon this parameters, ferromagnetic film can be observed as material with low and high level of absorption. Thus, when the radiation passes through the magnetic layer there are possible both the total absorption energy and the process without energy dissipations.

Corticosterone is known to accumulate in brain after various stressors including alcohol intoxication. Just as severe alcohol intoxication is typically required to impair memory formation only high concentrations of ethanol (60mM) acutely inhibit long-term potentiation (LTP), a cellular memory mechanism, in naïve hippocampal slices. This LTP inhibition involves synthesis of neurosteroids, including allopregnanolone, and appears to involve a form of cellular stress. In the CA1 region of rat hippocampal slices, we examined whether a lower concentration of ethanol (20 mM) inhibits LTP in the presence of corticosterone, a stress-related modulator, and whether corticosterone stimulates local neurosteroid synthesis. Although low micromolar corticosterone alone did not inhibit LTP induction, we found that 20 mM ethanol inhibited LTP in the presence of corticosterone. At 20 mM, ethanol alone did not stimulate neurosteroid synthesis or inhibit LTP. LTP inhibition by corticosterone plus ethanol was blocked by finasteride, an inhibitor of 5α-reductase, suggesting a role for neurosteroid synthesis. We also found that corticosterone alone enhanced neurosteroid immunostaining in CA1 pyramidal neurons and that this immunostaining was further augmented by 20 mM ethanol. The enhanced neurosteroid staining was blocked by finasteride and the N-methyl-D-aspartate antagonist, 2-amino-5-phosphonovalerate (APV). These results indicate that corticosterone promotes neurosteroid synthesis in hippocampal pyramidal neurons and can participate in ethanol-mediated synaptic dysfunction even at moderate ethanol levels. These effects may contribute to the influence of stress on alcohol-induced cognitive impairment.

Radar is a very important sensor in surveillance applications. Near-space vehicle-borne radar (NSVBR) is a novel installation of a radar system, which offers many benefits, like being highly suited to the remote sensing of extremely large areas, having a rapidly deployable capability and having low vulnerability to electronic countermeasures. Unfortunately, a target detection challenge arises because of complicated scenarios, such as nuclear blackout, rain attenuation, etc. In these cases, extra care is needed to evaluate the detection performance in blackout situations, since this a classical problem along with the application of an NSVBR. However, the existing evaluation measures are the probability of detection and the receiver operating curve (ROC), which cannot offer detailed information in such a complicated application. This work focuses on such requirements. We first investigate the effect of blackout on an electromagnetic wave. Performance evaluation indexes are then built: three evaluation indexes on the detection capability and two evaluation indexes on the robustness of the detection process. Simulation results show that the proposed measure will offer information on the detailed performance of detection. These measures are therefore very useful in detecting the target of interest in a remote sensing system and are helpful for both the NSVBR designers and users.