DESIGN OF DECENTRALIZED VARIABLE-STRUCTURE STABILIZERS FOR MULTIMACHINE POWER-SYSTEMS

Variable structure (VS) stabilizers possess the advantages of better t ransient response, insensitivity to plant parameter variations, etc. I n general, variable structure controls involve measurements from all t he states, which is not possible in a multimachine power system (MMPS) . In this paper, the switching planes for the variable structure stabi lizers are selected in such a way that computation of switching planes involves local state variables only. The coefficients of the switchin g plane equation are determined using the Riccati equation approach. T hrough the approximation of neglecting non-diagonal blocks of the stat e space matrix, at the design stage, a decentralized Variable Structur e stabilizer (VS stabilizer) is obtained To accept the switching plane so obtained, a check of the closed loop eigenvalues is made with the actual state space matrix. After computation of the switching plane, t he variable gains are also selected in such a way that control signal computation involves only local state variables. This is possible as t he gains of nonlocal stale variables are small compared with local var iables, The response of the system with variable structure stabilizers indicates that the system performance is improved. Copyright (C) 1996 Elsevier Science Ltd.