Blackout

About: Blackout is a research topic. Over the lifetime, 2088 publications have been published within this topic receiving 30433 citations.

Stochastic Analysis of Cascading-Failure Dynamics in Power Grids

Abstract: A scalable and analytically tractable probabilistic model for the cascading failure dynamics in power grids is constructed while retaining key physical attributes and operating characteristics of the power grid. The approach is based upon extracting a reduced abstraction of large-scale power grids using a small number of aggregate state variables while modeling the system dynamics using a continuous-time Markov chain. The aggregate state variables represent critical power-grid attributes, which have been shown, from prior simulation-based and historical-data-based analysis, to strongly influence the cascading behavior. The transition rates among states are formulated in terms of certain parameters that capture grid's operating characteristics comprising loading level, error in transmission-capacity estimation, and constraints in performing load shedding. The model allows the prediction of the evolution of blackout probability in time. Moreover, the asymptotic analysis of the blackout probability enables the calculation of the probability mass function of the blackout size. A key benefit of the model is that it enables the characterization of the severity of cascading failures in terms of the operating characteristics of the power grid.

Examining criticality of blackouts in power system models with cascading events

Abstract: As power system loading increases, larger blackouts due to cascading outages become more likely. The authors investigate a critical loading at which the average size of blackouts increases sharply to examine whether the probability distribution of blackout sizes shows the power tails observed in real blackout data. Three different models are used, including two simulations of cascading outages in electric power transmission systems. They also derive and use a new, analytically solvable model of probabilistic cascading failure which represents the progressive system weakening as the cascade proceeds.

Robustness of Interdependent Networks: The case of communication networks and the power grid

Abstract: In this paper, we study the robustness of interdependent networks, in which the state of one network depends on the state of the other network and vice versa. In particular, we focus on the interdependency between the power grid and communication networks, where the grid depends on communications for its control, and the communication network depends on the grid for power. A real-world example is the Italian blackout of 2003, when a small failure in the power grid cascaded between the two networks and led to a massive blackout. In this paper, we study the minimum number of node failures needed to cause total blackout (i.e., all nodes in both networks to fail). In the case of unidirectional interdependency between the networks we show that the problem is NP-hard, and develop heuristics to find a near-optimal solution. On the other hand, we show that in the case of bidirectional interdependency this problem can be solved in polynomial time. We believe that this new interdependency model gives rise to important, yet unexplored, robust network design problems for interdependent networked infrastructures.

A Study of Self-Organized Criticality of Power System Under Cascading Failures Based on AC-OPF With Voltage Stability Margin

Abstract: From the perspective of self-organized criticality, this paper develops a novel model with AC-OPF and AC grid upgrade to study the cascading failures and blackouts in power systems, which overcomes some shortcomings of existing blackout models. The proposed model contains two types of dynamics, one is fast dynamics which simulates the serial blackouts in power systems, the other is slow dynamics which reflects the tendency of the power systems time evolution. This model also has voltage stability analysis function and can reveal critical characteristics from reactive power and voltage viewpoint. Simulation results of the IEEE 118-bus system with this model show that the fast dynamics can capture the cascading process and the criticality property in micro scale. Besides, the macro scale of self-organized criticality of power systems can be revealed from the mean value of fractional overloads and the ratio of total load demand to the total network transfer capability. Furthermore, the voltage stability criticality status could be detected from the eigenvalue with the smallest magnitude through reactive power and voltage relevant modal analysis.

Alcoholic "blackouts": a review and clinical study of 100 alcoholics.

Abstract: In the past 25 years, numerous publications have cited "blackouts" as a major prodromal symptom of alcoholism. In contrast, this study, based on a structured interview with 100 hospitalized alcoholics, revealed that more than one-third of the subjects had never experienced a blackout and that, among those who did report the experience, blackouts generally began well along in the course of alcoholism rather than at an early stage. Blackouts were positively associated with severity and duration of alcoholism, extent and duration of alcohol consumption per drinking episode, capacity for drinking large amounts, "loss of control," neglect of meals, gulping drinks, and a history of head trauma. Only one patient had experienced blackouts after moderate drinking.