Reliability analysis of the protection system in smart substations

Aiming at implementing the condition based maintenance of protection systems in smart substation, a new assessment method of the operational level of protection systems is presented. Based on the characteristics of smart substations, a monitoring method reflecting the changes of the protection system function in terms of logical nodes was given first. According to the needs of the condition-based maintenance, reliability indices of the protection system were then selected. Along with these indices, a dynamic Markov reliability assessment model was built to quantitatively calculate the maintenance requirement under given conditions. Finally, a typical 220kV smart substation was utilized to illustrate the application method of the assessment model. The result shows that the method, with certain operability, could provide reference for maintenance decision-making of the protection system in smart substations.