An approach to improve the pss performance and tuning process considering uncertainty in excitation system model using a novel grouping scheme

Utilizing of the power system stabilizer (PSS) is a common approach to eliminate the low frequency power swings. The phase lag that must be compensated by the PSS to increase the damping of the system efficiently should be carefully obtained from the excitation system; but, the uncertainty in the excitation system data is an unavoidable issue and must be eliminated. This paper utilizes a comparative study of different AC excitation system models on a large-scale power grid to investigate the impact of uncertain information on the compensation angle and then PSS design and tuning. Moreover, this paper presented a new grouping scheme for the excitation systems based on similarity in the value of phase shift. Using this scheme, the excitation models of each group will share similar parameters for PSS tuning which can improve the stability for all excitation system models in the same group. So, the excitation system with inaccurate information can be replaced with an alternative model in the same group to be used for PSS tuning. The efficiency of the grouping scheme has been validated using the four-machine two-area, The New England and Iran national power grid.