Optimal pilot bus selection for the secondary voltage control using parallelism The scientific monograph submitted deals with the subject of power system set and its control on the secondary level. The power system can be characterized due to its size complexity and load unknown in advance in addition to time variability. Since large electric power is transferred even small changes in setting can frequently represent significant economic savings. Regarding the power system properties as well as the basics of secondary control it is obvious that the optimal selection of pilot bus plays an important role in the quality of control and the related economic impact. The monograph focuses on the methods of optimal selection of the pilot buses for the dispatch control of bus voltage in a complex power system. The aim is to modify them so that it is possible to investigate the issue via using the parallelism principle and grid computer structure aimed at multiple shortening of the computing time.