An ILMI approach to robust fault detection filter for a drum boiler system through a time-domain H-index norm method

Robust fault detection filter (RFDF) is mainly designed to detect faults in linear time-invariant (LTI) systems inherently exposed to external disturbances. H-index norm technique is one of the RFDF designing methods. The main idea of our study is to apply a continuous H-index method to a real boiler model which is made proper by adding an auxiliary direct channel. A high pass filter is augmented to raise the high frequency response. The H-index norm is maximized to distinguish between external disturbance and fault. The designed RFDF is continuous and can directly be implemented to the time-domain original continuous model. Furthermore, discretizing the continuous model may cause losing some information. Finally, the designed method is theoretically applied in a simulated model of a drum boiler operating in Synvendska Kraft AB Plant in Malmo, Sweden as a multivariable and strongly coupled system. It is illustrated that both sensor and actuator faults can robustly be detected as quickly as possible. To the best of authors´ knowledge, this is the first time that the continuous H-index norm procedure is employed to detect actuator and sensor faults in a boiler model.