Considering ICT in reliability assessment of system protection scheme

Special protection schemes (SPS) have been implemented by many utilities to maintain power system integrity. Successful operations of SPS depend on reliable sensors, actuators, controllers and data processing units involved. In the past, if performance analysis of SPS is conducted, only the reliability of processing and decision systems is considered assuming that the data needed for correct operations are always available. However, experiences have indicated that the performance of information and communication technologies (ICT) adopted plays an essential role of the SPS dependability. In this paper, by adopting a stochastic-flow network to model the effect of communication network and a fault tree technique to model the causes of failure on demand, we present reliability assessment results of a local SPS deployed in Taiwan power system.