Performance Assessment And Fault Detection Of Control System

With the development of control theory and technology, more and more control loops are applied in the process industry. These controllers always can achieve good performance at the beginning, but it will become worse some time later because some factors have been changed. Now it is easy to obtain large amount of data due to widely used DCSs. It is necessary to assess the control performance from these data. Firstly, in this paper, the different methods of control performance assessment and industrial application are introduced. Secondly, the methods of control performance assessment based on the minimum variance control are emphasized. The simulation of the power plant deaerator level control system shows that it is very useful method to monitor the condition of the control loops. Finally, based on the minimum variance of the control output, a fault diagnosis of cascade control systems is introduced. A new scheme to assess the performance of a superheated steam temperature control system is proposed. The simulation results demonstrate that the fault can be diagnosed exactly.