To enable an in-depth study of active cyber-physical distribution network, a cyber subsystem model is urgently needed to describe the performance in distribution communication. The methods for quantifying the interactions between subsystems, especially indirect interactions, have not been adequately studied in the existing research. In this paper, a novel model is developed to evaluate the validity of cyber link considering dynamic routing, delay, and communication error, particularly the cyber traffic. Then, an analytical method is presented to quantify the impact of cyber faults considering the functionality validity during distribution automation. And the reliability of cyber and physical subsystems is evaluated based on Non-Sequential and Sequential Monte Carlo methods respectively. Finally, a test system for reliability evaluation is established to analyze the influences of cyber faults. Also sensitivity analyses on the impact of cyber network traffic, element failure rate, and network topology and access communication technology are carried out. The obtained results could provide useful insights into planning and operation of active cyber-physical distribution networks.

The cyber system in Cyber Power System (CPS) is used to actively control the operation boundary of power system. Once cyber system fails, it will lead to power flow violation. Therefore, it is necessary to evaluate the voltage quality under cyber failures. This paper presents a research scenario that the influence of cyber system on normal operation of power system. Considering the active voltage control characteristics, voltage fluctuation index is proposed. Based on this, sequential Monte Carlo simulation method is used to calculate the voltage index under cyber failures. Finally, a test system is established to verify the method, which provides technical support for CPS.