Power system reliability evaluation considering cyber-malfunctions in substations

Protection system failures have been recognized as major causes of expanded outages and thereby affect bulk power system reliability. With the rapid progress of smart grid technologies, legacy protection systems with hardwired architecture are being gradually replaced by computer and communication networks consisting of multi-functional and smart Intelligent Electronic Devices (IEDs). In this paper, a systematic methodology for considering the effect of cyber-malfunctions in substations on power system reliability is proposed by extending the concepts we previously presented. The Roy Billinton Test System (RBTS) is extended to include substation protection systems with modern architecture, which is an important step as a test system like this is currently unavailable. The proposed approach is then demonstrated on this test system. The quantitative relationship between switching time and system-wide energy unavailability is studied. The results of our study clearly indicate the impact of protection system failures on system-wide reliability indices and signify the importance of accelerating line switching process. Furthermore, the overall methodology used in this paper provides a tractable and scalable option for the reliability evaluation of large cyber-physical power systems.