In the cyber-physical power system(CPPS)

the failure or malicious attack on cyber system may cause load loss in the physical system. To solve this problem

a method considering the effective distance based closeness centrality for analyzing the importance of cyber devices is proposed. Firstly

a weighted digraph is abstracted from the cyber system for quantitative analysis. Then

the weight of each edge is calculated based on the reliability influence of cyber system on the physical system. After that

the concept of effective distance is introduced to evaluate the closeness centrality via effective distance for each node

which can quantitatively analyze the cyber device importance from the perspective of load loss. Finally

by sorting the importance degrees of cyber devices in the testing system

the effectiveness of the method is verified. This work is supported by the Key Program of National Natural Science Foundation of China(No. 51537010)

National Basic Research Program of China(973 Program)(No. 2013CB228206)and Zhejiang Provincial Natural Science Foundation of China(No. LZ14E070001).