Design and reliability analysis of emergency trip system with triple modular redundancy

According to the high-reliability requirement of emergency trip system (ETS) for steam turbine, a triple modular redundant ETS system is presented in detail in this paper. The system consists of groups of input modules gathering data from sensors, system bus, main controllers running the same application program, and groups of output modules, all of which are configured to triple hardware redundancy with auto-testing and diagnosis function. The parameters synchronization strategy is designed to ensure the real-time and accurate system response, while the adaptable voting mechanism considering auto-testing fault table of system modules is used to ensure the system reliable. By analyzing the system structure and principle, the system reliability model is established. The simulation results and field commissioning proved the triple modular redundant ETS system has a better reliability and stability than the single module system.