Showing papers on "Blackout published in 2010"

Do topological models provide good information about electricity infrastructure vulnerability

Abstract: In order to identify the extent to which results from topological graph models are useful for modeling vulnerability in electricity infrastructure, we measure the susceptibility of power networks to random failures and directed attacks using three measures of vulnerability: characteristic path lengths, connectivity loss, and blackout sizes. The first two are purely topological metrics. The blackout size calculation results from a model of cascading failure in power networks. Testing the response of 40 areas within the Eastern U.S. power grid and a standard IEEE test case to a variety of attack/failure vectors indicates that directed attacks result in larger failures using all three vulnerability measures, but the attack-vectors that appear to cause the most damage depend on the measure chosen. While the topological metrics and the power grid model show some similar trends, the vulnerability metrics for individual simulations show only a mild correlation. We conclude that evaluating vulnerability in power networks using purely topological metrics can be misleading.

Do topological models provide good information about vulnerability in electric power networks

Abstract: In order to identify the extent to which results from topological graph models are useful for modeling vulnerability in electricity infrastructure, we measure the susceptibility of power networks to random failures and directed attacks using three measures of vulnerability: characteristic path lengths, connectivity loss and blackout sizes. The first two are purely topological metrics. The blackout size calculation results from a model of cascading failure in power networks. Testing the response of 40 areas within the Eastern US power grid and a standard IEEE test case to a variety of attack/failure vectors indicates that directed attacks result in larger failures using all three vulnerability measures, but the attack vectors that appear to cause the most damage depend on the measure chosen. While our topological and power grid model results show some trends that are similar, there is only a mild correlation between the vulnerability measures for individual simulations. We conclude that evaluating vulnerability in power networks using purely topological metrics can be misleading.

Review of Leading Approaches for Mitigating Hypersonic Vehicle Communications Blackout and a Method of Ceramic Particulate Injection Via Cathode Spot Arcs for Blackout Mitigation

Abstract: Vehicles flying at hypersonic velocities within the atmosphere become enveloped in a "plasma sheath" that prevents radio communication, telemetry, and most importantly, GPS signal reception for navigation. This radio "blackout" period has been a problem since the dawn of the manned space program and was an especially significant hindrance during the days of the Apollo missions. An appropriate mitigation method must allow for spacecraft to ground control and ground control to spacecraft communications through the reentry plasma sheath. Many mitigation techniques have been proposed, including but not limited to, aerodynamic shaping, magnetic windows, and liquid injection. The research performed on these mitigation techniques over the years will be reviewed and summarized, along with the advantages and obstacles that each technique will need to overcome to be practically implemented. A unique approach for mitigating the blackout communications problem is presented herein along with research results associated with this method. The novel method involves the injection of ceramic metal-oxide particulate into a simulated reentry plasma to quench the reentry plasma. Injection of the solid ceramic particulates is achieved by entrainment within induced, energetic cathode spot flows.

When the Lights Went Out: A History of Blackouts in America

Abstract: Blackouts-whether they result from military planning, network failure, human error, or terrorism-offer snapshots of electricity's increasingly central role in American society. Where were you when the lights went out? At home during a thunderstorm? During the Great Northeastern Blackout of 1965? In California when rolling blackouts hit in 2000? In 2003, when a cascading power failure left fifty million people without electricity? We often remember vividly our time in the dark. In When the Lights Went Out, David Nye views power outages in America from 1935 to the present not simply as technical failures but variously as military tactic, social disruption, crisis in the networked city, outcome of political and economic decisions, sudden encounter with sublimity, and memories enshrined in photographs. Our electrically lit-up life is so natural to us that when the lights go off, the darkness seems abnormal. Nye looks at America's development of its electrical grid, which made large-scale power failures possible and a series of blackouts from military blackouts to the "greenout" (exemplified by the new tradition of "Earth Hour"), a voluntary reduction organized by environmental organizations. Blackouts, writes Nye, are breaks in the flow of social time that reveal much about the trajectory of American history. Each time one occurs, Americans confront their essential condition-not as isolated individuals, but as a community that increasingly binds itself together with electrical wires and signals.

Focusing on Demand Side Management in the Future of the Electric Grid

Abstract: The widespread blackout that occurred on August 14, 2003 (“the blackout”) exposed the weaknesses of the current electric transmission grid structure, and underscored the need for improvements to the transmission grid in the United States. The outage knocked out power to approximately fifty million people in Ohio, Michigan, Pennsylvania, New York, Vermont, Massachusetts, Connecticut, New Jersey and the Canadian province of Ontario. 1 The total cost in the United States was estimated to be between $4 and $10 billion.

Load recognition for automated demand response in microgrids

Abstract: Microgrids are well-suited for electrification of remote off-grid areas. This paper sketches the concept of a plug-and-play microgrid with a minimum of configuration effort needed for setup. When the load of such an off-grid microgrid grows over the generation capacity and energy storage is not sufficient, demand has to be reduced to prevent a blackout. In order to decide which loads are inessential and can be shedded, automated load recognition on the basis of measured power consumption profiles is needed. Two promising approaches from the area of speech recognition, Dynamic Time Warping and Hidden Markov Models, are compared for this application. It is found that a key feature to achieve good recognition efficiency is a careful selection of the features extracted from the measured power data.

Modeling of electromagnetic manipulation of plasmas for communication during reentry flight

Abstract: Radio blackout that occurs during hypersonic reentry flight is an important issue for the operation of the vehicle. Since the radio blackout problem is caused by a high plasma number density around a vehicle, it is necessary to manipulate the plasma to allow communication. We suggest a configuration of an E B layer as a reentry blackout mitigationmethod.ThesuggestedE Blayerconfigurationwithatwo-dimensionalmagnetic fieldissimulatedusing thethermalized potentialmodelandthePoisson-like modelin ordertoillustrate theeffectiveness of thisapproachas amitigationmethod.Thenumericalmodelusesamagnetohydrodynamicsapproximationandissolvedusinga finite volumemethodwithaRiemannsolver.Theresultsofthenumericalmodelareassessedusingavailableexperimental results.Astrongplasmadensityreductionisobtainedwhenthehighelectricandmagnetic fieldsareappliednearthe cathode. The manipulated plasma region provides a possibility to communicate through a plasma layer during a reentry blackout.

Mitigation of cascading failures by real-time controlled islanding and graceful load shedding

Abstract: This paper presents an emergency control strategy, which serves to counteract a cascading disturbance in a large power system that would eventually lead to a blackout. The strategy is composed of two parts: after a disturbance, a real-time controlled islanding algorithm based on slow coherency of synchronous generators and k-means clustering splits the system into autonomously operating parts. The imbalances between load and generation are then accounted for by generator tripping in the generation-rich islands and a novel type of under-frequency load shedding in the load-rich islands, if the available primary control reserves are insufficient or too slow to stabilize the frequency. As opposed to the under-frequency relays in substations which are often used nowadays, the system considered here utilizes a “smart home” communication and control infrastructure for assigning frequency thresholds to individual appliances owned by consumers. Pervasive availability of this infrastructure is assumed. The strategy is evaluated in time-domain simulations using the IEEE 118-bus system.

Comprehensive Load-Shedding System

Abstract: The availability of reliable electrical power supply for petrochemical industries is extremely important not only to maintain continuous production but also from the point of view of overall plant safety. The costs, caused by production losses, due to a partial or a complete blackout easily run up to millions of dollars per blackout. If a proper load-shedding scheme is implemented, it is possible to save a plant from such occurrences. A lack of electrical power can be caused by loss of generation capacity or disconnection from the public power company supply. The load-shedding system ensures the availability of electrical power to all essential and most critical loads in the plant. This is achieved by switching off nonessential loads in the case of a lack of power in the plant electrical network, or parts of the plant electrical network. This paper discusses a comprehensive load-shedding scheme for industrial applications with a background on a similar system implemented at large integrated complexes such as refineries and petrochemical plants.

The Impacts of Natural Disasters on Power Systems: Anatomy of the Marmara Earthquake Blackout

Abstract: An earthquake is an instantly occurring and unpredictable natural event. The potential and effects of earthquakes and other natural disasters on power systems are system faults. The faults are not only limited to the physical damage of power systems, but power quality disturbances may also take place. The Marmara Earthquake, which occurred in Turkey on Aug 17, 1999, caused death and catastrophe. After the earthquake, the Turkish Power System collapsed. This is the largest power blackout in Turkey in last twenty years. In this study, the impact of the Marmara earthquake on the Turkish power system are described and the Marmara Earthquake Blackout is examined in detail as regards the qualitative behavior of the power system.

Analysis and Lessons of the Blackout in Brazil Power Grid on November 10,2009

Abstract: On November 10,2009,a widespread electrical blackout occurred in Brazil.The pre-fault situation,causes,spread and restoration of the blackout are described in this paper based on the official investigation report of Brazil Operador Nacional do Sistema Eletrico(ONS).The lessons and experiences of the blackout are analyzed and summarized.Some recommendations for guaranteeing the security and stability of China Power Grid and preventing the occurrence of blackout in China are presented.

Monitoring of a large scale event in the Brazilian Power System by WAMS

Abstract: On November 10, 2009 a fault at the AC Itaipu transmission system led to a large scale blackout of the Brazilian Interconnected Power System (BIPS) with a 40% load loss. This event was recorded at outlet voltage by a synchronized phasor measurement prototype, the LVPMS, with PMUs (Phasor Measurement Units) installed in nine universities throughout Brazil. The recorded data contain relevant information on the events leading to the blackout and the BIPS restoration.

A Review of Mechanism of Large Cascading Failure Blackouts of Modern Power System

Abstract: The mechanism of cascading failure blackout of modern power system is expounded According to different starting points of modelling, the research on cascading failure blackout is divided into two branches: one of the branch is based on power flow calculation and stability analysis, in which modelling analysis and events mode search strategy based on complex system theory are presented; the other is based on the research of power system network topology, which mainly focuses on the small-world network model and the scale-free network model Finally, some possible key technical problems to be solved for the research on cascading failure blackout of power system are pointed out

Security schemes of power systems against blackouts

Abstract: a security scheme of the power systems should protect the integrity of the electric networks and carry out fast operations on the entire power system to prevent a possible blackout. Blackouts started as local failures led to electrical disturbances, and the complete collapse of the power systems. This work proposes a security scheme based in two stages. In the first stage, the controlled separation of the power system allows to isolate the failure area. In the second stage, under frequency load shedding control actions should be applied to maintain a balance between consumption and generation power. This work presents some schemes in the IEEE-39 test system.

Challenges and Opportunities in Emergency Management of Electric Power System Blackout

Abstract: With the development of industrialization and informatization, modern society is highly dependent on energy. Electric power system is fundamental for social production and daily life. Especially in urban areas, electric power network has been a key infrastructure of the lifeline, and its failure will probably paralyze the whole city. On the other hand, as population growth and urbanization, the demand for electricity is overwhelmingly increasing. Electric power network is getting larger and more complex. Meanwhile, modern electric power network is unprecedented vulnerable and modern society is faced with higher blackout risk. In order to effectively prevent blackout risk and rapidly response the blackout accident, emergency management of electric power system are responsible for preparedness, mitigation, response, and recovery of its failure. Blackout is one of the most severe accidents in electric power system failure, and is paid great attention all the time. In recent decades, many techniques have been developed for effective prevention and control of blackout. This paper analyzes the core requirements and major challenges of prevention and response of blackout. And then, some potential advanced techniques on planning, monitoring and early-warning, emergency response, etc. are introduced in view of latest research progress.

Critical Interrelations Between ICT and Electricity System

Abstract: The widespread blackouts of 2003 have exposed the critical role of ICT systems in maintaining reliable operation of power systems Fundamental errors in providing back-up and alarm function in the control room were one of the main contributing factors to the 2003 USA/Canada blackout The lack of proper ICT infrastructure to enable proper communication and cooperation between system operators in Italy and Switzerland led to delayed remedial actions and the consequent blackout of Italy in 2003 Improved ICT systems would enable a better real-time cooperation and coordination between utilities in an interconnected power system but the main challenge is political: overcoming resistance of individual utilities to give up partially their interdependence and operate within the paradigm of a distributed, but coordinated, control Emergence of GPS-synchronised Wide Area Measurement Systems (WAMS) holds a great promise for improved monitoring and control of modern power systems and therefore avoiding future blackouts

Analysis on Causes of Blackout Occurred in Brazilian Power Grid on Nov. 11, 2009 and Lessons Drawn From It to China Southern Power Grid

Abstract: The occurrence and propagation of blackout in Brazilian power grid on Nov. 11, 2009 are retrospected. It is pointed out that at the first stage the accident was caused by extreme-weather, and then it extended to a serious multiple-failure and finally became blackout; the major causes expending the accident to blackout were the defects of protective relayings, security and stability control, the insufficient measures in "the third defense line" and the voltage collapse at receiving system. There are a lot of similarities in operational characteristics between Brazilian power grid and China Southern power grid, so considering actual condition of China Southern power grid the lessons from the blackout occurred in Brazilian power network are summarized.

Protection security assessment - An important task for system blackout prevention

Abstract: Protection security assessment of power grids becomes an important task in the course of a competitive energy business and a decarbonized power generation. The analysis of past blackouts studied by the North American Electric reliability Council (NERC) shows that protection relays are involved in about 75% of all major disturbances. One reason for that is the non adequate adaption of the protection systems to the changing network conditions. In particular the relay hidden failures causes relay malfunctions and blackouts in the past. This paper is presenting a new automated method for blackout prevention. It analyzes and assesses the security of protection systems of networks as a whole. Routinely checks of contingency sequences are carried out and reveal bottlenecks of the protection behavior itself and of the coordination of network and protection. The numerical simulation tool PSS®SINCAL is used providing the possibility of a holistic simulation of network and protection behavior on a fully automated manner. The handling of the big amount of resulting data is done by an intelligent visualization method like a “finger print” analysis.

Distribution panel with current management function

Abstract: PROBLEM TO BE SOLVED: To provide a distribution panel with a current management function capable of continuing power supply from an emergency power source even in the case where a blackout continues for an extended period.SOLUTION: A trunk breaker 12 is connected to a trunk line 4 to which an emergency power source 5 is connected. A general circuit switch 14 equipped with an opening/closing control part 15 which is controlled for its opening/closing by a blackout recovery signal inputted from outside is connected to the secondary side of the trunk breaker 12. A branch circuit 16 for supplying power to a general load is provided on the secondary side of the general circuit switch 14. A specific load emergency circuit 13 is connected parallel to the general circuit switch 14. At the time of blackout, the general circuit switch 14 is turned off to cut off supplying of power to the general load. Only the emergency circuit 13 is supplied with power from the emergency power source 5.

Earlier detection of risk of blackout by real-time dynamic security assessment based on Extreme Learning Machines

Abstract: The lack of real-time tools capable of detecting risk of blackouts is one of the contribution factors to the recent large blackouts occurred around the world. In terms of dynamic security assessment (DSA), artificial intelligence and data mining techniques have been widely applied to facilitate very fast DSA for enhanced situational awareness of insecurity. However, many of the current state-of-the-art models usually suffer from excessive training time and complex parameters tuning problems, leading to their inefficiency for real-time implementation. In this paper, a new DSA method using Extreme Learning Machine (ELM) is proposed, which has significantly improved the learning speed and can therefore provide earlier detection of the risk of blackout. The proposed method is examined on the New England 39-bus test system, and compared with other state-of-the-art methods in terms of computation time and accuracy. The simulation results show that the ELM-based DSA method possesses superior computation speed and acceptably high accuracy.

The Role of Yunnan-Guangdong ±800 kV DC Project in CSG Black-Start and Recovery Process

Abstract: Analyzing the main operation modes,back-start power plants of Yunnan-Guangdong ±800 kV DC project as well as its converter station power supply,the role of the project in the black-start and recovery process of China Southern Power Grid (CSG) is discussed,and furthermore a scheme for the black-start of the project in the case of CSG blackout is studied,including the basic condition,typical path,black-start process and control.Finally,it is advised to add the proposed scheme into the actual CSG black-start and system recovery precept.

Service Restoration Strategy for Blackout of Distribution System With Distributed Generators

Abstract: An agent-environment-rule(AER) model was proposed to solve the service restoration problem in the event of a blackout in a power distribution network with distributed generators(DGs).Various factors during service restoration of distribution system with DGs were expressed as agents,environment and interactive rules.Integrating with multi-agent-system(MAS),the proposed model constructs a lattice-like environment,and all agents can sense their local environment and move in it.By use of asynchronous backtracking algorithm to solve the AER model,the position of each agent in solution space was continuously updated through the interaction among agents and mutual influence between environment and agents to make the agents possible to search optimal solution quickly.The example results indicate the superiority and effectiveness of the proposed method.

Optimal load shedding scheme under contingency condition considering voltage stability problem

Abstract: Rapidly increasing demands in power systems at present may cause overloading of power system equipment. In some situations, these overloading lead to severe blackout unless proper load shedding is performed in time. The load shedding scheme must be effective and optimal in order to protect the power system from voltage instability. This paper proposes a new load shedding scheme under contingency condition considering voltage stability problem. The proposed method is based on the linearized optimization method. Moreover, rather than considering load as a constant power demand, more accurate model is used. The proposed method has been tested with the EGAT Thailand system. Satisfactory results have been obtained.

Method and appliance for the detection of current discontinuity in switched electrical point of an alternating network

Abstract: Method and appliance which detects if the interruption of current to an electrified load which is connected to a switched electrified point of an alternating network was by the user volition, or is due to a general electrical blackout, or if there was no interruption of electrification. With the aid of a microcontroller, the network voltage is calculated and then, by measuring period T, existence of rectification is calculated, in order to determine the status of switch (3), namely if half sine period is detected the switch is open and if a full sine period is detected the switch is closed, both cases with user volition, without the occurrence of a general electrification blackout, in which case the command is executed via the existing AC load control relay (25), while battery (9) always remains in charge mode, while if it is detected that the Period is equal to infinity, then there has been a general electrical blackout, operation is switched into rechargeable battery (9) operation and external load (13) is connected via power circuit (12).

The design of remote modification and verification system of the setting value without blackout in Fujian power grid

Abstract: Aiming at the technical difficulties of modifying setting value without blackout, this paper brings forward detailed solutions. Through analyzing the equipment situation of Fujian power grid, it compares several programs for remote verification and modification of the setting value without blackout, then recommends utilizing substation computer monitoring system to realize remote verifying and modifying setting value. In addition, it introduces main function, detailed process, equipment configuration and security measures of the remote modification and verification system of the setting value.

Integrated device having energy feedback and blackout emergent functions

Abstract: An integrated device having energy feedback and blackout emergent functions is composed of an energy feedbacker, a storage battery controller and a storage battery (group). The energy feedbacker is based on the theory of active inversion phase width control, uses lock phase ring technology to track grid synchronization to determine inversion output voltage phase angle and amplitude as PWM controlamount, ensures to feedback electricity to the grid with unit power factor, and supplies electricity in an independent power generation manner when the grid is cut off. The storage battery controlleris based on separated DC/DC conversion to recharge the storage battery (group) and supply electricity to DC bus from the storage battery when the grid is cut off. The energy feedbacker begins to generate electricity within half cycle of blackout of the grid, for the elevator system, the power supply is no different from power supply of the grid. The invention has the following characteristics: 1.the increase of the system cost is small; 2. average system energy saving is over 30%; 3. system wiring is almost unchanged and reliability is not influenced; and 4. emergency security is vastly improved, and the elevator is more humane as a special device.

Analysis of the Power Blackout in the Marmara Earthquake

Abstract: An earthquake occurred on August 17, 1999 in Turkey and the Turkish Power System was adversely affected by the earthquake. Therefore, the power system collapsed. In this study, it was examined the power blackout on the system and technically analyzed by MATLAB simulation program. Voltage profiles of the region are shown in graphics.

Power system security analysis: Applications for wind power allocations and smart islanding

Abstract: Power system reliability is the overall objective in power system design and operation. It includes two main aspects: adequacy and security. During the last decades, outages and blackout emerged more and more frequently which affected the normal consumption of consumers. In order to meet the increase the power system security, a self-healing grid is needed to monitor and response to the change within the whole network in time. Smart islanding is considered as an effective way to prevent small outages in the system from propagating into big blackout. In this paper, two common methods used to find the islands are introduced and the formation of islands was conducted by a C++ minimal cutset algorithm based program which was implemented on the platform of Dev cpp in the simulation part, moreover the proposed approach was applied to a Nordic 32-bus test system and was used to save the network from voltage collapse. On the other hand, since the large amounts of sustainable resources are being widely used by taking into account of the ever-increasing load demand throughout the world, people are exploring new resources to replace the existing non-renewable resources. As one of the renewable energy, wind power, draws people‟s attentions more and more. Renewable resource generation connected to the existing network will incur plenty of problems which will decrease the power system reliability. The wind energy injection will probably induce transmission overloaded problem which reduce the power system adequacy. It is critical to allocate the wind energy optimally. In order to find good locations to set up large-scale wind power projects, a Weighted Transmission Loading Relief (WTLR) / Equal Transmission Loading Relief (ETLR) sensitivity was introduced in this work to help find the positions of injecting the wind power so that the increasingly load demand can be satisfied as well as reduce the contingency overloads within the system to enhance the power system reliability.