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Abstract. Problem definition: A large proportion of the world's population has no access to electricity and so relies on noxious kerosene for their lighting needs. Solar-based solutions require a large [...]

In 2005, wind-induced structural damage from Hurricane Katrina resulted in extensive energy supply disruptions across the Gulf of Mexico. In this paper, we examine the resilience of these systems with a particular emphasis on the electric power delivery systems. We investigate the correlations of the power outage data with weather parameters such as wind speed, rainfall, and storm surge. We examine the resilience and recovery of the electric delivery system spatially and temporally and compare the results with other natural disasters. We conclude that the behavior of the delivery systems under hurricane loadings is affected by rainfall and storm surge as well as wind speed. Widespread failures may occur at wind speeds less than predicted peak values. DOI: 10.1061/(ASCE)EY.1943-7897.0000028 CE Database subject headings: Electric power; Disaster recovery; Hurricanes; Restoration. Author keywords: Electric power outages; Disaster recovery; Hurricanes; Resilience; Restoration.

The article studies the failure pattern of complex mechanical systems with Bounded Bathtub Intensity Process (BBIP) model. Findings reveal that BBIP model describes adequately the failure pattern of complex mechanical systems.

A new decomposition method is presented that includes the network through ac modeling within the hydrothermal scheduling optimization process including the losses. In short-term hydrothermal scheduling, the transmission network is typically modeled with dc power flow techniques. Such modeling, however, can lead to impractical solutions when it is verified with ac power flow. Another proposal considers in thermal systems the ac network modeling but not the optimization of losses. The approach presented here addresses issues such as congestion management and control of service quality that often arise in large and weakly meshed networks--the typical pattern of power systems in Latin America. Generalized Benders decomposition and traditional, well-known optimization techniques are used to solve this problem. The master problem stage defines the generation levels by regarding the inter-temporal constraints, whereas the subproblem stage determines both the active and the reactive economical dispatches for each time interval of the load curve. It meets the electrical constraints through a modified ac optimal power flow (OPF). Another important contribution is the inclusion of accelerating techniques aimed at reducing the number of iterations and CPU time. The methodology was proven in a real system and test systems. Results are discussed in this paper. Index Terms--Benders decomposition, hydrothermal scheduling, optimal power flow, unit commitment.

The risk of blackouts is inherent in complex power systems, despite all efforts to prevent their occurrence. To mitigate the consequences of major blackouts, better restoration plans have been demanded. Commonly, these plans consist of a set of actions textually described. In order to enhance the operating staff comprehension about the restoration plan, this paper proposes a methodology, based on CPM/PERT graph theory, that allows power system restoration plans to be graphically visualized. This approach permits to clearly see the precedence relations among activities and to graphically follow the restoration process during its execution. The methodology can also take advantage of calculations involved with CPM/PERT methods to evaluate the restoration duration and the plan critical path. The application of the proposed approach is illustrated using the IEEE 30-bus network and the restoration plan developed for a portion of the Brazilian interconnected power system. Index Terms--Blackout mitigation, CPM/PERT, graphical user interface, graph theory, power system restoration.

This paper presents a risk evaluation based approach to the replacement strategy of aged HVDC components. It includes estimation of unavailability of individual HVDC components due to aging failures, calculation of capacity state probabilities of the HVDC system, quantified risk evaluation of the power system containing the HVDC link and benefit/cost analysis for different replacement strategies. The presented approach can be also applied to other system components. The replacement strategy for an aged submarine cable of the HVDC link in a power supply system at British Columbia Transmission Corporation has been analyzed as an example to demonstrate the actual application. The procedure of the analysis has been explained in detail in the example. Index Terms--Aging failures, HVDC system, power system reliability, replacement strategy, risk evaluation.

On July 12, 2004 at 12:39 local time, the south part of the Hellenic 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. Some qualitative conclusions drawn immediately after the blackout are presented, as well as the results of further studies, including detailed simulations with corrected data, generator adjustments, and protection considerations. Index Terms--Armature current limit, blackout, loadability limit, voltage collapse, voltage instability.

The '318 Blackout Incident' at the Maanshan Nuclear Power Station on March 18, 2001, is considered to be the most serious event over the 24-year history of nuclear power generation in Taiwan. This paper simulates a special overvoltage phenomenon that occurred 4 h before the blackout event, which could have caused the incident. The simulation results almost coincide closely with the actual conditions recorded. We found two major low-frequency and ferroresonant overvoltages caused by the motors which acted as generators when they lost power supply, interacting with power-line capacitance and power transformers. Since overvoltages were present for a short period, the breaker insulation did not break down immediately but the defects were accumulated. A blackout eventually occurred 4 h later, when the power supplied to the 4.16-kV essential bus A changed over from the 161-kV system to the 345-kV system, due to damage in the incoming breaker insulation. Index Terms--Blackout, ferroresonance (FR), generating effect, island system, nuclear power station, overvoltage.

A comprehensive methodology is developed for the analysis of power system vulnerability with respect to energy shortage, capacity shortage, and power system failures. The basic method is risk analysis, where risk is defined in terms of the probability of events and their consequences. The objective is to identify medium- and high-risk situations that require corrective actions. The method is applied to the Nordic power system. The results show that the system is in a medium-risk state, implying the need to consider various measures. With respect to energy shortage, the probability of extremely high prices over a sustained period of time is once every ten years for today's system and similar in 2010. With respect to capacity shortage, the vulnerability is expected to deteriorate toward 2010. With respect to blackouts, the risk is related to large blackouts in southern Scandinavia, involving many consumers. There is concern with regard to the future effect of changed maintenance routines and reductions in qualified technical personnel. Index Terms--Blackout, capacity shortage, energy shortage, risk analysis, security of supply.

THERE'S NOTHING LIKE a massive blackout to spur a little energy introspection. When the lights went down across eastern Canada and the US on August 14, 2003, everyone with a […]

This paper presents two approaches for the calculation of the average outage duration (AOD) of diversity systems over generalized fading channels. First, a 'classical' probablility density function (pdf)-based approach is used to obtain exact closed-form expressions for the AOD of maximal-ratio combiner (MRC) over independent and identically distributed (i.i.d.) Rayleigh and Rice fading channels. On the other hand, relying upon a numerical technique for inverting Laplace transforms of cumulative distribution functions, and in conjunction with the calculation of the joint characteristic function (CF) of the combined output signal-to-noise ratio process and its time derivative, a CF-based approach is adopted to compute the AOD of MRC over non-i.i.d. Rayleigh and Rician diversity paths. The mathematical expressions are ilustrated by presenting and interpreting numerical results/plots, showing the impact of the power delay profile, the angles of arrival, and the angle spreads on the AOD of diversity systems operating over typical fading channels of practical interest. Index Terms--Average fade duration, average outage duration, characteristic function, diversity combining, fading channels, level-crossing rate.

This paper uses trajectory sensitivity analysis to investigate a major disturbance of the Nordel power system which occurred on January 1, 1997. The Nordel system is described, and the details of the disturbance are presented. Background to trajectory sensitivity analysis is also provided. Results of the investigation indicate the usefulness of trajectory sensitivities for exploring the influence of various system parameters on the large disturbance behaviour of the system. The trajectory sensitivities provide a way of judging the relative importance of various factors which affected behaviour. Keywords: Disturbance analysis, trajectory sensitivities, security assessment.

Wavelets introduce new classes of basis functions for time-frequency signal analysis and have properties particularly suited to the transient components and discontinuities evident in power system disturbances. Wavelet analysis involves representing signals in terms of simpler, fixed building blocks at different scales and positions. This paper examines the analysis and subsequent compression properties of the discrete wavelet and wavelet packet transforms and evaluates both transforms using an actual power system disturbance from a digital fault recorder. The paper presents comparative compression results using the wavelet and discrete cosine transforms and examines the application of wavelet compression in power monitoring to mitigate against data communications overheads. Keywords: Wavelets, Fourier transforms, disturbances, data compression

In a competitive energy market in which power supply reliability can influence customer purchasing decisions, electric utilities throughout the world are rapidly recognizing that they cannot ignore customer preferences. Today's energy market is characterized by intense price competition, and electric utilities are faced with new challenges of large debts, budget constraints, safety, environment and economic issues, lower load growth than in the past, need for more involvement of public at large in the planning and design process, and more competitive nonconventional suppliers of electricity. In addition, in a deregulated competitive energy market, electric utilities are under conflicting pressures of providing even higher standards of service reliability and holding the line on rates. Value-based system facility planning offers a rational response to these conflicting customer demands. This paper presents two case studies to illustrate the basic concepts and applications of value-based power system planning. The paper also presents a methodology for determining the unique composite customer cost of interruptions (i.e., damage functions) for changing area system network configurations. These techniques are presently being used in the decision-making processes at Alberta Power Limited, Edmonton, Alta., Canada. Index Terms - Competitive market, deregulation, interruption costs, reliability cost/reliability worth, value-based.

This paper presents the results of an investigation conducted by the Power Systems Research Group at the University of Saskatchewan to determine the costs of electric service interruptions in the government, institution and office building sector. The methodology used to obtain customer interruption cost information in this sector and to analyze the results is also presented.