Robust non-linear observer for islanding detection of inverter based Distributed Generation

This paper provides the design of a robust nonlinear adaptive observer for the purpose of islanding detection of inverter based Distributed Generation (DG). The non-linear observer provides simultaneous online estimates for the amplitude and frequency of a noisy sinusoidal signal where amplitude estimation values will be used to determine the existence of islanding condition or not. The main goal of this paper is to provide analytical derivations and proofs of robustness and convergence for the proposed non-linear observer and to utilize results of proposed observer for the islanding detection problem. The IEEE 34-bus system with inverter-based DGs is used to demonstrate the effectiveness of the proposed observer.