Cascading Failure A nalysis of Cyber Physical Power Systems Considering Routing Strategy
ABSTARCT :
In this brief, we develop a novel model to study the cascading failure in cyber-physical power systems. We use a discrete packet traffic model that follows a specific routing strategy to describe the dynamic data transmission in the information network. Moreover, the dynamic load flow model that takes into account the power-frequency characteristics of loads and generators is applied to describe the dynamic flow process of the power network. Our proposed model allows to consider the impacts of data packet transmission failures and voltage-related failures in the cascading process. Furthermore, we analyze the effects of routing strategy and information network topology on the severity of cascading failure. Simulation results verify the applicability of the proposed model and reveal the way in which routing strategy affects the cascading failure of cyber-coupled systems. In addition, we show that when the main hub in the information network is used as a dispatching center, a spreadout degree distribution of the information network reduces the severity of cascading failure in the cyber-coupled system.
EXISTING SYSTEM :
? The initial network consists of three nodes and three edges. Every two nodes are connected by an edge. Each time, add a new node to the network which is connected to two existing nodes in the current network.
? The probability that the new node will be connected to an existing node depends on the degree of the existing node.
? Cyber nodes are the abstractions of cyber devices and related algorithms, such as SAS. Cyber edges are the abstractions of communications links. Scale-free network is a typical complex network which widely exists in the real world.
? In this paper, a CPPS model, which consists of cyber layer, physical layer and cyber-physical interface, is presented using complex network theory.
DISADVANTAGE :
? It is in need for research on modeling of communication network, and the coupling relation with physical power grid.
? Further, the effect from communication network should be additionally added into the problem that analyzes the vulnerability of physical power grid.
? This case can cause great damage on systems, such as traffic jam in transportation system, short circuit in physical power grid, information congestion in communication networks, etc.
? In giant component evaluation results, the robustness index of systems almost maintains the same value in many scenes when different node falls faulty, difficult to distinguish their difference of damage on systems.
PROPOSED SYSTEM :
• A cyber-physical equivalent model for a hierarchical control system (HCS) had been proposed in .
• The HCS network was abstracted to a node-branch graph using this model, and information flow was expressed by a series of mathematical equations for the sake of cyber-contingency assessment.
• A vulnerability analysis method is proposed, and the CPPS performance before and after cascading failures is analyzed by the proposed method to calculate vulnerability indices.
• The impact of direct cyber-power interdependencies (DCPIs) was also studied in , and risk assessment methods under different distributed generation (DG) scenarios were proposed.
ADVANTAGE :
? In cyber-physical power systems, the main function of physical devices is to transmit power energy/control commands, and the state of physical devices directly affects transmission efficiency of systems.
? Although these quantitative indexes can be employed to evaluate the vulnerability of systems, the evaluation result merely concerns the statistical analysis of surviving nodes or links in systems, which is unable to analyze the entire performance of systems.
? We evaluate systems vulnerability in cascading failure in terms of two evaluation approaches, efficiency index and giant component approaches.
? By means of advanced Information and Communication Technology (ICT), cyber-physical power systems can better realize the aim of real-time monitor and dynamic adjustment in contingency.
|