DAMPING OF TORSIONAL OSCILLATIONS-A COORDINATED APPROACH

Abstract

Damping of torsional oscillations using coordinated control through power system stabilizer (PSS) and thyristor controlled reactor(TCR) is presented in this paper. The PSS has modal speed deviations as its feedback signal.The reactive power control is achieved through thyristor controlled reactor (TCR) at the machine terminals. Generator speed deviation is used as auxiliary signal and terminal voltage feedback signal as main control signal for TCa. The followingcontrol strategies have been analysed : a PSS with modal speed control b PSS with modal speeds plus TCR with terminal voltage control c PSS with modal speeds plus TCa with complete controls (voltage feed back signal and generator speed deviation signal) Themain objective of this paper is to diseuse the modelling aspects and analyse different control strategies for damping torsional oscillations in series compensated ac transmission system. The control parameters like gains and time constants have been obtained by performing repeated eigenvalue analysis. IEEE First Benchmark Model is considered for illustration