Showing papers on "Blackout published in 2005"

Causes of the 2003 major grid blackouts in North America and Europe, and recommended means to improve system dynamic performance

Abstract: On August 14, 2003, a cascading outage of transmission and generation facilities in the North American Eastern Interconnection resulted in a blackout of most of New York state as well as parts of Pennsylvania, Ohio, Michigan, and Ontario, Canada. On September 23, 2003, nearly four million customers lost power in eastern Denmark and southern Sweden following a cascading outage that struck Scandinavia. Days later, a cascading outage between Italy and the rest of central Europe left most of Italy in darkness on September 28. These major blackouts are among the worst power system failures in the last few decades. The Power System Stability and Power System Stability Controls Subcommittees of the IEEE PES Power System Dynamic Performance Committee sponsored an all day panel session with experts from around the world. The experts described their recent work on the investigation of grid blackouts. The session offered a unique forum for discussion of possible root causes and necessary steps to reduce the risk of blackouts. This white paper presents the major conclusions drawn from the presentations and ensuing discussions during the all day session, focusing on the root causes of grid blackouts. This paper presents general conclusions drawn by this Committee together with recommendations based on lessons learned.

Blackout Prevention in the United States, Europe, and Russia

Abstract: Tens and hundreds of thousands of disturbances occur annually in modern power systems. The overwhelming majority of them are eliminated by relay protection devices and other automatic systems and by the actions of the dispatching personnel. A small fraction of the emergencies (tens of cases in such large power interconnections as those in the United States and Canada, Europe, and the United Power System (UPS) of Russia) result in significant system failures, sometimes of a cascading nature. They are consequences of unusual primary disturbances, failures of automatic emergency control systems, protection device malfunctions, and errors by personnel, but do not cause extreme consequences for the power system and the consumers. Of these, only some rare failures-blackouts-become catastrophes with severe long-term consequences for the national economies and population. Recent blackouts in North America, Europe, Russia, and other countries require specialists once again to pay closer attention to the blackout phenomenon. It is often believed that the philosophy of preventing blackouts should be based on dispatching personnel training, wide-area system visibility,and better computer models for the analysis of the stability and security of power systems. The authors of this paper also think that in emergency situations of a cascading nature, automatic emergency control systems should play a major role. A confirmation for this statement is the fact that from 1975 to 2005 there were no blackouts in the UPS of Russia (where automatic emergency control systems are widely used). At the same time, the Moscow blackout demonstrated that the growing problems in the Russia's UPS (such as aging equipment and load growth) made it also vulnerable to major blackouts. This stresses again that the electrical power industry faces common global problems and that a global effort, cooperation, and exchange of the best practices are needed to prevent blackouts. This paper describes the Russian

Control strategies for microgrids emergency operation

Abstract: Under normal operating conditions, a microgrid (MG) is interconnected with the medium voltage (MV) network. However, planned or unplanned events like maintenance or faults in the MV network, respectively, may lead to MG islanding. In order to deal with islanded operation and even black start following a general blackout, an emergency operation mode must be envisaged. Two possible control strategies were investigated and are described in this paper in order to operate a MG under emergency mode. A sequence of actions for a well succeeded black start procedure, involving microgeneration units, has also been identified contributing for an increase in distribution network reliability

Preventing Future Blackouts by Means of Enhanced Electric Power Systems Control: From Complexity to Order

Abstract: This paper concerns the critical role enhanced control will play in the operating of future electric power systems reliably and efficiently. The nonstandard control problems are due to a large variety of controllers, presently acting in a multirate mode at various levels of the system. Today's monitoring and control logic is largely effective during normal conditions. This paper concerns its possible enhancements which might enable the system to operate reliably over broader ranges of loading and equipment status. In particular, it is suggested that major benefits could come from providing computer tools to assist human operators with their decision making when the system is under stress. A multilayered approach is introduced to support:1) on-line adjustment of available resources; 2) monitoring the interconnection based on qualitative indices (QIs) essential for deciding the severity of the operating mode; and 3) using the QIs to adjust structure of control as the system evolves from one mode to the next. An equivalenced model of the Northeast Power Coordinating Council (NPCC) interconnection is used to illustrate the potential of enhanced control in scenarios that resemble the blackout of August 2003. Also, the potential for efficient use of the resources during normal conditions is illustrated using this multilayered monitoring and control architecture.

Branching Process Models for the Exponentially Increasing Portions of Cascading Failure Blackouts

Abstract: We introduce branching process models in discrete and continuous time for the exponentially increasing phase of cascading blackouts. Cumulative line trips from real blackout data have portions consistent with these branching process models. Some initial calculations identifying parameters and using a branching process model to estimate blackout probabilities during and after the blackout are illustrated.

Microgrids black start and islanded operation

Abstract: A low voltage distribution network with large amounts of small sized dispersed generation can be operated as an isolated system in certain conditions. This paper presents the control strategies to be used in such a system to deal with islanded operation and to exploit the local generation resources as a way to help in power sys- tem restoration after a general blackout. A sequence of actions for the black start procedure is identified and it is expected to be an advantage for power system operation in terms of reliability as a result from the presence of a very large amount of dispersed generation.

Identification of severe multiple contingencies in electric power networks

Abstract: In this paper we propose a two-stage screening and analysis process for identifying multiple contingencies that may result in very severe disturbances and blackouts. In a screening stage we form an optimization problem to find the minimum change in the network to move the power flow feasibility boundary to the present operating point and that will cause the system to separate with a user-specified power imbalance. The lines identified by the optimization program are used in a subsequent analysis stage to find combinations that may lead to a blackout. This approach is applied to a 30-bus system with encouraging results.

Blackout 2003: preparedness and lessons learned from the perspectives of four hospitals.

Abstract: Introduction:The blackout in North America of August 2003 was one of the worst on record. It affected eight United States states and parts of Canada for >24 hours. Additionally, two large United States cities, Detroit, Michigan and Cleveland, Ohio, suffered from a loss of water pressure and a subsequent ban on the use of public supplies of potable water that lasted four days. A literature review revealed a paucity of literature that describes blackouts and how they may affect the medical community.Methods:This paper includes a review of after-action reports from four inner-city, urban hospitals supplemented accounts from the authors' hospital's emergency operations center (emergency operations center).Results:Some of the problems encountered, included: (1)lighting; (2) elevator operations; (3) supplies of water; (4) communication operations; (5) computer failure; (6) lack of adequate supplies of food; (7) mobility to obtain Xray studies; (8) heating, air condition, and ventilation; (9) staffing; (10) pharmacy; (11) registration of patients; (12) hospital emergency operations center; (13) loss of isolation facilities; (14) inadequate supplies of paper; (15) impaired ability to provide care for non-emergency patients; (16) sanitation; and (17) inadequate emergency power.Discussion:The blackout of 2003 uncovered problems within the United States hospital system, ranging from staffing to generator coverage. This report is a review of the effects that the blackout and water ban of 2003 had on hospitals in a large inner-city area. Also discussed are solutions utilized at the time and recommendations for the future.Conclusion:The blackout of 2003 was an excellent test of disaster/emergency planning, and produced many valuable lessons to be used in future events.

Estimating Failure Propagation In Models Of Cascading Blackouts

Abstract: We compare and test statistical estimates of failure propagation in data from versions of a probabilistic model of loading-dependent cascading failure and a power system blackout model of cascading transmission line overloads. The comparisons suggest mechanisms affecting failure propagation and are an initial step toward monitoring failure propagation from practical system data. Approximations to the probabilistic model describe the forms of probability distribution of cascade sizes.

Protection issues during system restoration

Abstract: Power system blackouts are a very rare phenomenon in a well-planned interconnected power system. Nevertheless it is very important to have plans and systems in place to handle any eventuality even if it is remote. This report brings out various issues related to protection during a system restoration process. Power system protection is critical to a safe, efficient, and reliable power system. Protection engineers take every possible care to ensure that protection systems are designed considering all predictable eventualities and these constraints have grown over time. However, during system restoration, after a major blackout, it is possible for the protection elements to be presented with situations, which they can mistake for an unhealthy power system and the protection elements may operate. The prime concern during a power system blackout is to bring the system back to normalcy as fast as possible. At times, if proper care is not taken, the protection system can hinder and delay the restoration of the power system. This report discusses various such conditions that can occur during the blackstart of a power system and also suggests solutions to manage them without compromising the objectives of protection system i.e., to ensure a safe, efficient, and reliable power system.

Autonomous agents and cooperation for the control of cascading failures in electric grids

Abstract: A power system can be thought of as a stochastic hybrid system: a finite state machine whose states involve continuous variables with uncertain dynamics. Transitions in this machine correspond to outages of generation and transmission equipment. A cascading failure corresponds to a series of such transitions whose net effect is a blackout. We present evidence that the probability of cascading failures is subject to phase transitions - large and abrupt changes that result from only small changes in system stress. We suggest a network of distributed, autonomous agents to reduce the ill effects of cascading failures. These agents improve their decisions by cooperating (sharing goals and exchanging information with their neighbors). Results from experiments on the IEEE 118 bus test case are included.

Blackouts in the US/Canada and continental Europe in 2003: Is liberalisation to blame?

Abstract: The paper starts with an overview of 2003 blackouts in the US, Sweden/Denmark and Italy in order to analyse common threads and lessons to be learnt. The blackouts have exposed a number of challenges facing utilities worldwide. Increased liberalisation of electricity supply industry has resulted in a significant increase in inter-area (or cross-border) trades which often are not properly accounted for when assessing system security. The traditional decentralised way of operating systems by TSOs, with each TSO looking after its own control area and little information exchange, resulted in inadequate and slow response to contingencies. A new mode of coordinated operation for real-time security assessment and control is needed in order to maintain system security. This new mode of operation requires overcoming a number of organisational, psychological, legal and technical challenges but the alternative is either to risk another blackout or run the interconnected system very conservatively, maintaining large security margin at a high cost to everyone.

Blackouts in North America and Europe: Analysis and generalization

Abstract: The paper describes the unique wide-spread power system blackouts that happened recently in the United States, Italy, Sweden-Denmark and other countries. The summary of observations and recommendations are made. The authors indicate the items already addressed in the Russian emergency control and protection system.

Benefits of FACTS for Power System Enhancement

Abstract: The performance of power systems decreases with the size, the loading and the complexity of the networks. This is related to problems with load flow, power oscillations and voltage quality. Such problems are even deepened by the changing situations resulting from deregulation of the electrical power markets. The power systems have not been designed for wide-area power trading with daily varying load patterns where power flows do no more follow the initial planning criteria of the existing network configuration. Large blackouts in America and Europe confirmed clearly, that the favorable close electrical coupling might also include risk of uncontrollable cascading effects in large and heavily loaded interconnected systems. FACTS (flexible AC transmission systems), however, provide the necessary features to avoid technical problems in the power systems and they increase the transmission efficiency

Dynamic real-time reconfiguration in distributed systems: timing issues and solutions

Abstract: Dynamic software reconfiguration is a useful tool to adapt and maintain software systems. In most approaches, the system has to be stopped while the reconfiguration is in progress. This is not suitable for real-time systems, even on small-embedded systems. Timing constraints must be met even while the system is reconfiguring. Our approach is based on the real-time middleware OSA+. Our main objective is to be able to reconfigure services during run-time, with a predictable and predefined blackout time (the time the systems does not react due to the reconfiguration). Three different approaches concerning the blocking or non-blocking state of a service are presented. These approaches can be used to realize a tradeoff between the reconfiguration time and the blackout time.

Blackout prevention by optimal insertion of FACTS devices in power systems

Abstract: Actual interconnected power systems are very large structures which suffer from a large gap between electricity demand and generation and from an inadequate transmission capacity of interconnection lines. In such systems, blackouts have become an all too common an occurrence. This paper proposes a method to reinforce the power systems by insertion of FACTS (flexible alternating current transmission system) devices, which are optimal placed in order to eliminate the dangerous contingencies of the systems and to prevent by this way the apparition of blackout if outages occurs. The FACTS devices are optimal placed in order to maximizing the power system security, the optimization is carried out using three parameters: the location of FACTS devices, their type and their sizes. For this purpose we developed a hybrid software based on GAs (genetic algorithms), which uses Matlabtrade and the EUROSTAGtrade software for load flow calculations. The proposed procedures are successfully tested on an IEEE 14-bus power system

Reducing blackout risk by a wide-area control system (wacs): adding a new layer of defense

Abstract: Large-scale blackout risk is greatly reduced by multiple layers of defense. With best practices for tree trimming, power system planning and design, control center operation, prioritized control and protection up- grades, automatic load shedding, special protection sys- tems, etc., blackout risk becomes very low. Wide-area feedback control for discontinuous actions such as genera- tor or load tripping and capacitor/reactor bank switching, is an advanced "special protection system." After reviewing blackouts and close calls in 1996, 1999, 2003, and 2004, we describe Bonneville Power Administra- tion (BPA) development and on-line demonstration of Wide-Area stability and voltage Control System (WACS). WACS uses phasor measurements from many stations as inputs, with existing special protection system transfer trip circuits available for outputs. We describe in detail WACS response and validation for the June 14, 2004 outage of 4600 MW of generation near Phoenix, Arizona.

Power Systems Frequency Dynamic Monitoring System Design and Applications

Abstract: Recent large-scale blackouts revealed that power systems around the world are far from the stability and reliability requirement as they suppose to be. The post-event analysis clarifies that one major reason of the interconnection blackout is lack of wide area information. Frequency dynamics is one of the most important parameters of an electrical power system. In order to understand power system dynamics effectively, accurately measured wide-area frequency is needed. The idea of building an Internet based real-time GPS synchronized wide area Frequency Monitoring Network (FNET) was proposed to provide the imperative dynamic information for the large-scale power grids and the implementation of FNET has made the synchronized observations of the entire US power network possible for the first time. The FNET system consists of Frequency Disturbance Recorders (FDR), which work as the sensor devices to measure the real-time frequency at 110V single-phase power outlets, and an Information Management System (IMS) to work as a central server to process the frequency data. The device comparison between FDR and commercial PMU (Phasor Measurement Unit) demonstrate the advantage of FNET. The web visualization tools make the frequency data available for the authorized users to browse through Internet. The research work addresses some preliminary observations and analyses with the fieldmeasured frequency information from FNET. The original algorithms based on the frequency response characteristic are designed to process event detection, localization and unbalanced power estimation during frequency disturbances. The analysis of historical cases illustrate that these algorithms can be employed in real-time level to provide early alarm of abnormal frequency change to the system operator. The further application is to develop an adaptive under frequency load shedding scheme with the processed information feed in to prevent further frequency decline in power systems after disturbances causing dangerous imbalance between the load and generation.

Experience from the Athens blackout of July 12, 2004

Abstract: On 12 July 2004 at 12:39 local time the south part of the Greek Interconnected Transmission System (including Athens) was split from the rest of the system and collapsed driving consumers with a total load of 4500 MW into blackout. Technical information about the causes, the evolution and the consequences of the blackout are presented in this paper. The report of a special committee appointed by the Ministry of Development of Greece immediately after the blackout is presented, as well the results of further studies including simulations with corrected data and generator adjustments.

Survey of the Research on the Complexity of Power Grids and Reliability Analysis of Blackouts

Abstract: A comprehensive account of a complex systems approach to large blackouts caused by cascading failure is given from the viewpoint of the statistics, dynamics and risk of series of blackouts with approximate global model. According to the analysis of a 15-year record of power outages occurred on the North American power grid provided by NERC, it suggests that the frequency of large blackouts is governed by a power law, and a more reasonable clustering property is also revealed. This result stimulates many theoretical models to come forth which are used to explain the mechanism of cascading of the blackouts in power gird. Moreover, inspired by concepts from self-organized criticality, we suggest that power grid operating margins evolve slowly to near criticality and the critical loads at which blackout risk sharply increase is an vital element to the risk of power system. To mitigate and prevent the blackouts, a new synthetical evaluation framework of power system risk must be established and we should try our best to find the force to reduce the risk of power system.

New control strategies to prevent blackouts: Intentional islanding operation in distribution networks

Abstract: Several countries have experienced electric system deregulation. The market deregulation is currently associated with deep changes in distributed resources (DR or DG) technologies and communication & information technologies (ICT). The massive connection of DR and the need to improve their profitability leads to new electric system management concepts. The article presents the possible use of DR to supply partially local distribution area, isolated from the interconnected electrical power system (EPS) during a blackout for instance. This technical capacity may be achieved at various scales and may last several hours during a restoration process following a blackout. This intentional islanding may result of an ultimate saving action for a specific area of the EPS, or of a black start in a local area. This specific EPS running mode leads to new kind of DR control and DNO operation tools, to a new fast adaptation of the local protection systems. Some existing areas in the distribution EPS may be relatively well adapted to manage the needed local agent. The size and the location of these possible cells are introduced in the paper. The typical voltage level targeted in the paper is the medium voltage (MV). The main interest is to take profit of a local production capacity (interest for the network operator, the consumer and the producer) to increase the local security and availability. But this profit has a cost: local control and protection reinforcement and real time adaptation. This paper gives information on some local area networks characteristics: possible topology flexibility, cell definition, need for a specific exploitation strategy (frequency and voltage control requirement), improvement needed for the protection system and for the local information system. The intentional islanding availability study is presented in the paper through a proposed methodology that may be automated in the long run. The approach proposed in this paper is essentially based on technical constraints. The methodology is applied to a study case and the results are illustrated using EUROSTAG software simulation. Finally, a few characteristics for the information system for the intentional islanding application are given. The works included in the article are integrated in the CRISP project (CRISP: Distributed Intelligence in Critical Infrastructures for Sustainable Power. Project funded by the European Community under the Fifth RTD Framework Program (2002–2005)).

Communications blackout predictions for atmospheric entry of Mars Science Laboratory

Abstract: The Mars Science Laboratory (MSL) is expected to be a long-range, long-duration science laboratory rover on the Martian surface. MSL will provide a significant milestone that paves the way for future landed missions to Mars. NASA is studying options to launch MSL as early as 2009. There are three elements to the spacecraft; carrier (cruise stage), entry vehicle, and rover. The rover has a UHF proximity link as the primary path for EDL communications and may have an X-band direct-to-Earth link as a back-up. Given the importance of collecting critical event telemetry data during atmospheric entry, it is important to understand the ability of a signal link to be maintained, especially during the period near peak convective heating. The received telemetry during entry (or played back later) allows for the performance of the entry-descent-landing technologies to be assessed. These technologies include guided entry for precision landing, a new sky-crane landing system and powered descent. MSL will undergo an entry profile that may result in a potential communications blackout caused by ionized particles for short periods near peak heating. The vehicle will use UHF and possibly X-band during the entry phase. The purpose of this report is to quantify or bound the likelihood of any such blackout at UHF frequencies (401 MHz) and X-band frequencies (8.4 GHz). Two entry trajectory scenarios were evaluated: a stressful entry trajectory to quantify an upper-bound for any possible blackout period, and a nominal trajectory to quantify likelihood of blackout for such cases.

Revision of the underfrequency load-shedding scheme of the Slovenian power system

Abstract: The main motivation for the study presented in this paper was the numerous blackouts that occurred in 2003. After the Italian blackout, which almost caused a collapse of the Slovenian power system as well, it became clear that some automatic procedures, with underfrequency load-shedding being one of the most important ones, need to be thoroughly revised. In the first part of the paper we deal with the frequency dynamic model that was developed to simulate the impact of the most important system parameters on the frequency response after a major disturbance. Next, we determined the optimal number of load-shedding steps and the amount of load to be shed in each step. We also checked whether it is necessary to use the frequency decline gradient in the underfrequency relaying scheme, which is currently not implemented. The simulations were performed on a detailed model of the Slovenian power system using the software package EUROSTAG. The proposed underfrequency relays' settings conform to the UCTE Operation handbook.

Blackouts, risk, and fat-tailed distributions

Abstract: We analyze a 19-year time series of North American electric power transmission system blackouts. Contrary to previously reported results we find a fatter than exponential decay in the distribution of inter-occurrence times and evidence of seasonal dependence in the number of events. Our findings question the use of self-organized criticality, and in particular the sandpile model, as a paradigm of blackout dynamics in power transmission systems. Hopefully, though, they will provide guidelines to more accurate models for evaluation of blackout risk.

Real Time Congestion Monitoring and Management of Power Systems

Abstract: The collapse of the US electric grid on August 14, 2003 caused the largest blackout in US history, knocking more than 100 power plants offline and leaving 50 million customers in the US and Canada without power. The old transmission systems that were built in the 60's or 70's are blamed for this outage. Certainly, it is time to upgrade and modernize the transmission system. But it is more important to predict and avoid ahead of real time the risks to the existing grid, or help the analysis of the real time situation in order to minimize the damage or provide the useful information for how to upgrade the grid. This paper proposes an approach of power systems real time congestion monitoring and management (RTCMM) to reach this goal. The proposed RTCMM system will be a collection of analysis, processes, computing equipment, measurement devices and communications that are assembled to provide the means to maintain a secure system state. The implementations of real time congestion monitoring and management are discussed in the paper

Blackout Prevention Plan – The Stability, Reliability and Security Enhancement in Thailand Power Grid

Abstract: The stability, reliability and security of power system are the concerned issues in Thailand due to the lessons from the blackout around the world in 2003. Electricity Generating Authority of Thailand (EGAT), which is responsible on the generation and transmission system in Thailand, has considered the measures to avoid the major power failure in Thailand so-called the blackout prevention plan. The blackout prevention plan is used as a tool for managing and operating the system efficiently. The blackout prevention plan is the preventive plan to minimize the chance of the failure in the power system in Thailand as possible. To identify the system vulnerability in the network, the power system simulations are performed as the important methodology. The power system analysis is not only examined on the N-1 criteria but also the events from the past experience and the potential events that can occur in the Thailand power grid. Many aspects are analyzed to understand the constraint on system and select the appropriate methods to solve the problems efficiently. The investment and maintenance cost of the solution also are taken into the account to optimize the security of the system and economics. This paper presents the blackout prevention plan for Thailand system. It is also addressed the power system analysis on the load flow study as well as the dynamic simulation. The enhancement of system strength is divided into the long term and short term duration. The construction of the new transmission lines and generators as well as the installation of new technologies equipment will be suggested to reinforce the system for the long term planning. As the short terms planning, the special protection schemes generally played the important role to maintain the system stability. The use of the special protection systems and the existing FACTS equipment in the system such as HVDC and SVC are expected to mitigate problems associated with the blackout in Thailand system. The implementation of special protection schemes and FACTS devices to increase the power system stability, reliability and security are represented in this paper. Applying the blackout prevention plan will be beneficial to Thailand power grid as a whole. This paper is the case study for the power system study and implementation on the blackout prevention plan to enhance the stability, reliability and security of the power system in Thailand

Methods and apparatus for blackout, retune and subscription enforcement in a cellular network multimedia distribution system

Abstract: A method for blackout, retune and roaming enforcement in a cellular network multimedia distribution system is disclosed. The method includes the acts of receiving a plurality of service regions in the cellular network multimedia distribution system; determining an affiliation of the client with one of the service regions in the plurality of service regions; and processing a service region specific message based on the affiliation. An apparatus, as well as a computer-readable medium having instructions stored thereon, the stored instructions, when executed by a processor, cause the processor to perform the method are also disclosed.

Self-organized criticality phenomenon for power system blackouts

Abstract: Applying complex system theory and by means of analyzing partial data of power system blackouts in America, the power law relation between the scale of power system blackout and system frequency and the fractal and fractol features of the distribution of power system blackout scale are investigated in detail. The viewpoint that blackout phenomena can be explained by the concept of self-organized criticality is proposed. Based on the Hurst exponent, it is pointed out that power system blackouts are predictable.