Higher Order Sliding Mode Observers and Nonlinear Algebraic Estimators for State Tracking in Power Networks

In this paper we propose a novel nonlinear observer-based approach to estimate and track the unmeasured state variables in power networks. We consider a power network comprising synchronous generators, which are modeled by nonlinear differential algebraic equations, and loads, which are modeled by nonlinear algebraic equations. We use an iterative discrete-time scheme to estimate the voltage magnitude and the voltage phase angle of each bus. Furthermore, we propose original higher sliding mode observers giving rise to a distributed observation scheme capable of locally estimating the frequency of each generator in a finite time. The proposed method is validated in simulations considering the IEEE 9 bus benchmark.