eng Science and Education Publishing American Journal of Electrical and Electronic Engineering 2328-7357 2017-02-20 5 1 28 33 10.12691/ajeee-5-1-5 AJEEE2017515 article Sajad Tashakori 1 Amir Tavakoli 2 Farzad Mirzaei farzadmirzaei7@yahoo.com 2 Electrical Department, Shiraz University of Technology, Shiraz, Iran Mechanical Department, Islamic Azad University of Shiraz, Shiraz, Iran In this paper the authors tried to design a under excitation limiter and a power system stabilizer which can operate without any kind of interaction. The under excitation limiter (UEL) is intended to prevent reduction of generator excitation to a level where the steady state stability limit or the stator core end-region heating limit is exceeded. The power system stabilizer (PSS) uses auxiliary stabilizing signals to control the excitation system so as to improve power system dynamic performance. http://pubs.sciepub.com/ajeee/5/1/5/ajeee-5-1-5.pdf power system operation stability under excitation limiter