2,595 research outputs found
Changes in Cascading Failure Risk with Generator Dispatch Method and System Load Level
Industry reliability rules increasingly require utilities to study and
mitigate cascading failure risk in their system. Motivated by this, this paper
describes how cascading failure risk, in terms of expected blackout size,
varies with power system load level and pre-contingency dispatch. We used Monte
Carlo sampling of random branch outages to generate contingencies, and a model
of cascading failure to estimate blackout sizes. The risk associated with
different blackout sizes was separately estimated in order to separate small,
medium, and large blackout risk. Results from secure models of the IEEE
RTS case and a 2383 bus case indicate that blackout risk does not always
increase with load level monotonically, particularly for large blackout risk.
The results also show that risk is highly dependent on the method used for
generator dispatch. Minimum cost methods of dispatch can result in larger long
distance power transfers, which can increase cascading failure risk.Comment: Submitted to Transmission and Distribution Conference and Exposition
(T&D), 2014 IEEE PE
The impact of a network split on cascading failure processes
Cascading failure models are typically used to capture the phenomenon where
failures possibly trigger further failures in succession, causing knock-on
effects. In many networks this ultimately leads to a disintegrated network
where the failure propagation continues independently across the various
components. In order to gain insight in the impact of network splitting on
cascading failure processes, we extend a well-established cascading failure
model for which the number of failures obeys a power-law distribution. We
assume that a single line failure immediately splits the network in two
components, and examine its effect on the power-law exponent. The results
provide valuable qualitative insights that are crucial first steps towards
understanding more complex network splitting scenarios
Interrelation of structure and operational states in cascading failure of overloading lines in power grids
As the modern power system is expected to develop to a more intelligent and efficientversion, i.e. the smart grid, or to be the central backbone of energy internet for freeenergyinteractions,securityconcernsrelatedtocascadingfailureshavebeenraisedwithconsideration of catastrophic results. The researches of topological analysis based oncomplex networks have made great contributions in revealing structural vulnerabilitiesof power grids including cascading failure analysis. However, existing literature withinappropriate assumptions in modeling still cannot distinguish the effects between thestructure and operational state to give meaningful guidance for system operation. Thispaper is to reveal the interrelation between network structure and operational statesin cascading failure and give quantitative evaluation by integrating both perspectives.For structure analysis, cascading paths will be identified by extended betweenness andquantitatively described by cascading drop and cascading gradient. Furthermore, theoperational state for cascading paths will be described by loading level. Then, the riskof cascading failure along a specific cascading path can be quantitatively evaluatedconsideringthesetwofactors.Themaximumcascadinggradientofallpossiblecascadingpaths can be used as an overall metric to evaluate the entire power grid for its featuresrelated to cascading failure. The proposed method is tested and verified on IEEE30-bussystem and IEEE118-bus system, simulation evidences presented in this paper suggest
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