@misc{BobtsovOrtegaNikolaevetal., author = {Bobtsov, Alexey and Ortega, Romeo and Nikolaev, Nikolay and Schiffer, Johannes}, title = {A Globally Convergent State Observer for Multimachine Power Systems with Lossy Lines}, series = {21st IFAC World Congress, Berlin, Germany, Jul. 11-17, 2020}, journal = {21st IFAC World Congress, Berlin, Germany, Jul. 11-17, 2020}, pages = {6}, abstract = {We present the first solution to the problem of estimation of the state of multimachinepower systems with lossy transmission lines. We consider the classical three-dimensional "flux-decay" model of the power system and assume that the active and reactive power as wellas the rotor angle and excitation voltage at each generator is available for measurement—ascenario that is feasible with current technology. The design of the observer relies on two recentdevelopments proposed by the authors: a parameter estimation based approach to the problemof state estimation and the use of the dynamic regressor extension and mixing technique toestimate these parameters. Thanks to the combination of these techniques it is possible toovercome the problem of lack of persistent excitation that stymies the application of standardobserver designs. Simulation results illustrate the performance of the proposed observer.}, language = {en} } @misc{LorenzMeyerBobtsovOrtegaetal., author = {Lorenz-Meyer, Nicolai and Bobtsov, Alexey and Ortega, Romeo and Nikolaev, Nikolay and Schiffer, Johannes}, title = {PMU-Based Decentralized Mixed Algebraic and Dynamic State Observation in Multi-Machine Power Systems}, series = {IET Generation, Transmission \& Distribution}, volume = {14}, journal = {IET Generation, Transmission \& Distribution}, number = {25}, issn = {1751-8695}, doi = {10.1049/iet-gtd.2020.1275}, pages = {6267 -- 6275}, abstract = {We propose a novel decentralized mixed algebraic and dynamic state observation method for multi-machine power systems with unknown inputs and equipped with Phasor Measurement Units (PMUs). More specifically, we prove that for the third-order flux-decay model of a synchronous generator, the local PMU measurements give enough information to reconstruct algebraically the load angle and the quadrature-axis internal voltage. Due to the algebraic structure a high numerical efficiency is achieved, which makes the method applicable to large scale power systems. Also, we prove that the relative shaft speed can be globally estimated combining a classical Immersion and Invariance (I\&I) observer with—the recently introduced—dynamic regressor and mixing (DREM) parameter estimator. This adaptive observer ensures global convergence under weak excitation assumptions that are verified in applications. The proposed method does not require the measurement of exogenous inputs signals such as the field voltage and the mechanical torque nor the knowledge of mechanical subsystem parameters.}, language = {en} }