A plant analyzer was developed for the Kuosheng power station, based on the AD-100 peripheral processor system. To analyze a transient from partial power conditions, the initial steady-state conditions must be generated in advance. A self-initialization algorithm for generating the initial partial power conditions has been developed. The initialization of the rated power conditions is performed first. The self-initialization algorithm then simultaneously adjusts important plant variables, such as the reactor power, dome pressure, downcomer level, feedwater temperature, and core flow, to the desired partial power conditions from the rated conditions with the aid of existing plant control systems and four extra control loops. This algorithm was developed and encoded in the Kuosheng plant analyzer. The initialization for a recirculation pump trip test at 68% of rated power demonstrates the success of this algorithm. The initial conditions generated can be saved and used for transient analysis. Tedious and time-consuming trial-and-error initialization procedures are eliminated. This methodology improves the accuracy and consistency of transient calculations for partial power conditions.