Services of different secure partitions in a power communication network are transmitted by the packet transport network(PTN)

whose isolation effects demand prompt verification. This paper focuses on the service security in the power communication network based on the label switching path(LSP)and pseudo-wire emulation edge-to-edge(PWE3)technology. From the perspective of security vulnerabilities

a risk association model is created to analyze the correlations between services of different secure partitions in the power grid. Experimental results show that in PTN networks

when network congestion occurs

services in secure area Ⅱ are slightly affected and the packet loss rate is nearly zero while time delay stability is high

which shows a good channel isolation in PTN. Services in secure area Ⅲ and Ⅳ are subject to different degrees of impact

and the average affected degrees are less than 1% and 10%

respectively. So the time delay variation in secure area Ⅲ is more stable than that of secure area Ⅳ. In addition

the influence propagation processes among elastic services are investigated. The results show that with an increase in the neighbor's order

the degrees of services affected are gradually reduced while time delay stability is increased

with an alternately positive and negative characteristics. All in all

if priorities and quality of service(QoS)of different secure partitions are rationally set

PTN will show a good channel isolation in ensuring safe transmission of information in the power grid. This work is supported by Beijing Natural Science Foundation(No. 4142036)and State Grid Corporation of China(No. SGRIXTKJ〔2015〕406).