Sensitivity and elasticity of multi-channel IEC-61850 Substation Communication Networks to imperfect repairs

The reliability, availability and system dynamics of a repairable multi-channel IEC-61850 based mission-critical Substation Communication Network with imperfect repairs can be determined by analysing the magnitudes and the layout formation of the eigenvalues of the transition probability matrix. The disadvantage of only using the eigenvalue analysis method is that it focuses on the asymptotic state of the system, and does not account for the system state transient behaviour, which makes the optimisation of the system at subsystem level to be challenging. In this paper, a complimentary analysis technique that advances the eigenvalue analysis method is presented based on the concept of absorbing Markov Chain and matrix calculus techniques. The objective of the study focuses on the responsiveness of the system reliability performance to repair factors. The results of the case studies indicate that system performance is very dependent on the diagnostic coverage of the individual subsystems compared to their repair efficiencies, particularly for high diagnostic coverages at 99% and 90% based on ISO 13849-1 for subsystems A and B in a 'one-out-of-two' scheme configuration. Therefore, the results reveal that emphasis should be more on the system diagnostic capability because it is embedded in the system design itself that cannot easily be changed at a later stage considering that it would be too expensive and require plant downtime for implementation and testing as well. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The paper analyzes the reliability, availability, and system dynamics of a repairable multi-channel IEC-61850 based substation communication network by examining the eigenvalues of the transition probability matrix. A complementary analysis technique is proposed to address the limitations of the eigenvalue analysis method. Results show that the system performance is more dependent on diagnostic coverage rather than repair efficiency, especially for high diagnostic coverages.