Research On Resilience Enhancement Methods Of Power Communication Coupled Network Considering Structure And Function Coupling

The reliance of power system operation and control on communication system is deepening,based on the structural coupling of fiber-optic composite overhead ground and the functional coupling of operation and control system with physical operation state,driving the physical system into power communication coupled system.Advanced communication technologies provide reliable guarantees for the routine operation of power systems,but extreme scenarios where common cause failures caused by structural fusion and cascading effects due to functional coupling will trigger more serious outages.For example,the primary cause of the South China blackout in 2009 was the cyber-physical composite lines broken due to ice disasters,which caused remedial control for physical outages fail.The reliability study of independent power/communication networks is no longer sufficient to support the safe operation of power grids,and the resilience of coupled networks has received attention.However,the existing research on the resilience of coupled networks is still in the exploratory stage,and both the resilience influencing factors and the dual network resilience enhancement scheme are still not clear and explicit.This paper takes the resilience of coupled network as the core.The research work is aimed at the modeling,vulnerability analysis,collaborative planning,collaborative harden and collaborative recovery of power communication coupled networks.The main research of this paper is as follows:(1)In view of coupling characteristics of the topology of power and communication network,a universal modeling method of power communication coupled network and the vulnerability analysis method based on accident chain theory are proposed.Considering the structural characteristics and networking constraints of fiber optic communication networks,the topology generation method is proposed based on the power network.In the case study the provincial transmission network in China is taken as an arithmetic example to verify that the generated communication network network has the same network characteristics as the actual network.On this basis,the functional coupling model,the chain failure model based on accident chain theory,the vulnerability assessment method are established.The simulation analysis shows that the structural coupling characteristic is the important factor affecting vulnerability.(2)For the pre-disaster planning stage,a two-layer robust expansion planning method for transmission/communication networkis proposed to collaboratively optimize transmission lines,communication lines,communication service routing and unit generation plans.The calculation method of load loss cost under extreme scenarios is proposed.Further,considering the small occurrence probability of the worst scenario in robust planning,which leads to overly conservative optimization results,a collaborative stochastic expansion planning model of power communication coupled network with resilience constraints is established.The simulation results show that the proposed method can reduce the threat of common cause failure caused by structural coupling and reduce the coupling impact of communication failure on the power system.(3)For pre-disaster line harden,a two-stage stochastic reinforcement planning model for power communication network frames considering the structural and functional coupling characteristics of dual networks is proposed.To take into account the scale and representativeness of the scenario set in the stochastic planning model,a Gaussian mixture model clustering-based approximate scenario set generation method is proposed.The mode is based on the mapping relationship between typhoon scenario damage characteristics and power communication coupled network failure loss,which realizes similar failure scenario clustering and simplification.The simulation results show that the proposed stochastic reinforcement scheme has strong adaptability while improving the solution speed of the stochastic programming model.(4)For post-disaster emergency repair,a two-stage collaborative optimization method is proposed for the pre-disaster repair station layout and post-disaster emergency repair.In the post-disaster fault repair stage,a fault element repair time model considering the fault element repair timing and the spatial-geographic distribution of the fault element is established.The cascading effects of the failure of economic dispatch control function and substation automation function on the load recovery of the power system are analyzed.The load recovery model of the power communication coupled network is established.The simulation results show that the proposed method can reasonably select the site of the emergency repair station by considering the communication weak area,power weak area and traffic convenience.Besides,the model considers the influence of communication failure on power emergency recovery,formulate the optimal power-communication fault equipment repair route,quickly restore the system power supply and reduce the total loss.