Power oscillation damping control using wide-area signals: A case study on Nordic equivalent system
Power oscillation damping (POD) control employing wide-area signals is illustrated in an equivalent system model representing key characteristics of Nordic power system. Phasor measurement units (PMUs) in Norway and Finland are used to obtain feedback signals for supplementary control of a large SVC unit located in the south-east of Norway. Comparison has been made between two control design approaches- (i) robust linear time invariant model based POD (MBPOD) - dependant on accurate system model and (ii) indirect adaptive POD (IAPOD) - which is fixed structure but time-varying and relies only on measurements. An optimization problem is formulated to design the controller parameters for MBPOD while the IAPOD is based on online Kalman filter estimation and adaptive pole-shifting control. Performances of both MBPOD and IAPOD are found to be quite similar even though IAPOD requires very little prior information about the system. A number of simulations are carried out under different tie-line outages to verify the performance.