A comparison and simulation study of nonlinearly designed robust controllers for power system transient stability

In this paper, the robust mechanical and excitation control algorithms, tog ether with power system stabilizer (PSS) are studied and compared. In light of the fact that theoretical results on Lyapunov stability have been estab lished for these control algorithms, effort has been concentrated in this p aper on comparisons between these algorithms and the conventional exciter a nd the PSS. It is shown through simulations on the 39-bus New England syste m that robust control algorithms are very effective in improving power syst em transient stability and that their combination shows a much better perfo rmance compared to that under any one of them. It is also through the simul ation study that the problem of how to select control gains is addressed. I n fact, it is shown that "optimal" gains exist and that they are not large. (C) 1999 Elsevier Science Ltd. All rights reserved.