Disturbance identification method of pressurized water reactor plant operated with automatic frequency control by applying projection operator technique

The identification method applying the projection operator for less small disturbances which do not instantly lead the alarm initiation has been extended to diagnose PWR plants operated with automatic frequency control. The authors previously proposed the non-linear transformation of the observed signals to satisfy with the linear relationship between the disturbances and the observed signals by utilizing several additional observed signals which are closely related with the non-linear characteristics of PWR plant. In addition, a method is proposed to compensate the fluctuation of observed signals due to automatic frequency control by utilizing both the input signal of the main steam valve control system and the input signal of the control rod control system. The effectiveness of the extended method has been examined by several computer experiments using a simple PWR plant simulation code. (author)