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For the grid and through the grid: The role of power line communications in the smart grid,” to appear
- in Proceedings of the IEEE, 2011. [Online]. Available: http://arxiv.org/abs/1010.1973
"... is to address this important question. To do so we provide an overview of what PLC can deliver today by surveying its history and describing the most recent technological advances in the area. We then address Smart Grid applications as instances of sensor networking and network control problems and ..."
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Cited by 36 (1 self)
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is to address this important question. To do so we provide an overview of what PLC can deliver today by surveying its history and describing the most recent technological advances in the area. We then address Smart Grid applications as instances of sensor networking and network control problems and discuss the main conclusion one can draw from the literature on these subjects. The application scenario of PLC within the Smart Grid is then analyzed in detail. Since a necessary ingredient of network planning is modeling, we also discuss two aspects of engineering modeling that relate to our question. The first aspect is modeling the PLC channel through fading models. The second aspect we review is the Smart Grid control and traffic modeling problem which allows us to achieve a better understanding of the communications requirements. Finally, this paper reports recent studies on the electrical and topological properties of a sample power distribution network. Power grid topological studies are very important for PLC networking as the power grid is not only the information source but also the information delivery system- a unique feature when PLC is used for the Smart Grid. Index Terms—Smart grid, power grid, power line communi-cations, power line channel, cyber-physical systems. I.
Criticality in a cascading failure blackout model
- International Journal of Electrical Power and Energy Systems
"... Abstract – We verify and examine criticality in a 1000 bus network with an AC blackout model that represents many of the interactions that occur in cascading failure. At the critical loading there is a sharp rise in the mean blackout size and a power law probability distribution of blackout size tha ..."
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Cited by 35 (9 self)
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Abstract – We verify and examine criticality in a 1000 bus network with an AC blackout model that represents many of the interactions that occur in cascading failure. At the critical loading there is a sharp rise in the mean blackout size and a power law probability distribution of blackout size that indicates a significant risk of large blackouts.
Stochastic model for power grid dynamics
- In Proc. of 40th Annual Hawaii International Conference on System Sciences
, 2007
"... Abstract — We introduce a stochastic model that describes the quasi-static dynamics of an electric transmission network under perturbations introduced by random load fluctuations, random removing of system components from service, random repair times for the failed components, and random response ti ..."
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Cited by 33 (1 self)
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Abstract — We introduce a stochastic model that describes the quasi-static dynamics of an electric transmission network under perturbations introduced by random load fluctuations, random removing of system components from service, random repair times for the failed components, and random response times to implement optimal system corrections for removing line overloads in a damaged or stressed transmission network. We use a linear approximation to the network flow equations and apply linear programming techniques that optimize the dispatching of generators and loads in order to eliminate the network overloads associated with a damaged system. We also provide a simple model for the operator’s response to various contingency events that is not always optimal due to either failure of the state estimation system or due to the incorrect subjective assessment of the severity associated with these events. This further allows us to use a game theoretic framework for casting the optimization of the operator’s response into the choice of the optimal strategy which minimizes the operating cost. We use a simple strategy space which is the degree of tolerance to line overloads and which is an automatic control (optimization) parameter that can be adjusted to trade off automatic load shed without propagating cascades versus reduced load shed and an increased risk of propagating cascades. The tolerance parameter is chosen to describes a smooth transition from a risk averse to a risk taken strategy. We present numerical results comparing the responses of two power grid systems to optimization approaches with different factors of risk and select the best blackout controlling parameter. PACS: 89.75.-k, 05.10.-a, 02.50.-r I.
Do topological models provide good information about electricity infrastructure vulnerability
, 2010
"... In order to identify the extent to which results from topological graph models are useful for modeling vulnerability in electricity infrastructure, we measure the sus-ceptibility of power networks to random failures and directed attacks using three measures of vulnerability: characteristic path leng ..."
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Cited by 30 (3 self)
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In order to identify the extent to which results from topological graph models are useful for modeling vulnerability in electricity infrastructure, we measure the sus-ceptibility 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. Electricity infrastructures are vital to the operation of modern society, yet they are notably vulnerable to cascad-ing failures. Understanding the na-ture of this vulnerability is fundamen-tal to the assessment of electric energy reliability and security. A number of articles have recently used topological
Long-Term Effect of the n-1 Criterion on Cascading Line Outages in an Evolving Power Transmission Grid
"... Abstract—Cascading transmission line outages contribute to widespread blackouts. Engineers respond to the risk of cascading line outages by applying policies such as the n-1 criterion and upgrading lines involved in recent cascading outages. The transmission grid slowly evolves as these policies are ..."
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Cited by 19 (7 self)
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Abstract—Cascading transmission line outages contribute to widespread blackouts. Engineers respond to the risk of cascading line outages by applying policies such as the n-1 criterion and upgrading lines involved in recent cascading outages. The transmission grid slowly evolves as these policies are applied to maintain reliability while the load grows. We suggest how to assess the long-term effect of these policies on the risk of cascading line outages by simulating both the cascading and the slow evolution of the transmission grid. The long-term effects of these policies on the probability distribution of outage size and the grid utilization are computed for the IEEE 118-bus test system. The results show complex system self-organization of an evolving transmission grid. Index Terms—Complex system, failure analysis, network reliability, power system security, power transmission reliability, risk analysis. I.
Using Transmission Line Outage Data to Estimate Cascading Failure Propagation in an Electric Power System
"... Abstract—We study cascading transmission line outages recorded over nine years in an electric power system with approximately 200 lines. The average amount of propagation of the line outages is estimated from the data. The distribution of the total number of line outages is predicted from the propag ..."
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Cited by 17 (6 self)
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Abstract—We study cascading transmission line outages recorded over nine years in an electric power system with approximately 200 lines. The average amount of propagation of the line outages is estimated from the data. The distribution of the total number of line outages is predicted from the propagation and the initial outages using a Galton–Watson branching process model of cascading failure. Index Terms—Failure analysis, power systems, reliability, risk analysis. I.
Power grid vulnerability to geographically correlated failures -- analysis and control implications
, 2011
"... We consider power line outages in the transmission system of the power grid, and specifically those caused by a natural disaster or a large scale physical attack. In the transmission system, an outage of a line may lead to overload on other lines, thereby eventually leading to their outage. While s ..."
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Cited by 14 (5 self)
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We consider power line outages in the transmission system of the power grid, and specifically those caused by a natural disaster or a large scale physical attack. In the transmission system, an outage of a line may lead to overload on other lines, thereby eventually leading to their outage. While such cascading failures have been studied before, our focus is on cascading failures that follow an outage of several lines in the same geographical area. We provide an analytical model of such failures, investigate the model’s properties, and show that it differs from other models used to analyze cascades in the power grid (e.g., epidemic/percolation-based models). We then show how to identify the most vulnerable locations in the grid and perform extensive numerical experiments with real grid data to investigate the various effects of geographically correlated outages and the resulting cascades. These results allow us to
Predicting Failures in Power Grids: The Case of Static Overloads
- SUBMITTED TO IEEE TRANSACTIONS OF SMART GRIDS
, 2010
"... Here we develop an approach to predict power grid weak points, and specifically to efficiently identify the most probable failure modes in static load distribution for a given power network. This approach is applied to two examples: Guam’s power system and also the IEEE RTS-96 system, both modeled w ..."
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Cited by 10 (4 self)
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Here we develop an approach to predict power grid weak points, and specifically to efficiently identify the most probable failure modes in static load distribution for a given power network. This approach is applied to two examples: Guam’s power system and also the IEEE RTS-96 system, both modeled within the static Direct Current power flow model. Our algorithm is a power network adaption of the worst configuration heuristics, originally developed to study low probability events in physics and failures in error-correction. One finding is that, if the normal operational mode of the grid is sufficiently healthy, the failure modes, also called instantons, are sufficiently sparse, i.e. the failures are caused by load fluctuations at only a few buses. The technique is useful for discovering weak links which are saturated at the instantons. It can also identify generators working at the capacity and generators under capacity, thus
Towards quantifying cascading blackout risk
- Bulk Power System Dynamics and Control-VII
, 2007
"... Blackouts become widespread by initial failures propagating in a diverse and intricate cascade of rare events. We describe this complicated cascade using a bulk probabilistic model in which the initial failures propagate randomly according to a branching process. The branching process parameters can ..."
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Cited by 10 (5 self)
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Blackouts become widespread by initial failures propagating in a diverse and intricate cascade of rare events. We describe this complicated cascade using a bulk probabilistic model in which the initial failures propagate randomly according to a branching process. The branching process parameters can be statistically estimated from observed data or simulations and then used to efficiently predict the probability distribution of blackout size. We review the current testing of these methods on simulations and observed data and discuss the next steps towards achieving verified and practical methods for quantifying cascading failure of electric power systems. The ability to efficiently quantify cascading blackout risk from observed data and simulations could offer new ways to monitor power transmission system reliability and quantify the reliability benefit of proposed improvements. 1
