Risk Assessment for Protection System in Smart Substation Considering Information Reachability

Widespread information and communication technology (ICT) and state monitoring technology can help to design a well-monitored protection system of smart substation, hence faults can be totally observed. However, there are limited effective methods that can be implemented to evaluate the risk of faults in smart substation protection system, threatening the reliability and safety of power system operation. This paper illustrates a network topology model for protection system in smart substation, where information transmits between devices. An optimized information reachability analysis algorithm is proposed to analyze whether information can reach its destination from source. Furthermore, a failure analysis tree of protection system is built to deduce the risk types caused by unreachable information. Lastly, a risk assessment method is proposed, which takes the importance of power equipment and risk type of secondary devices into consideration. Case study has showed that the proposed algorithm and method can efficiently distinguish different faults and evaluate their risks. Therefore, the effectiveness and necessity of proposed algorithm and method can be verified.