A Kalman Filter-Based Protection Strategy for Microgrids /

Abstract

Recently the concept of Microgrids has emerged in the world due to the penetration of the renewable energy resources (RERs) at the distribution end. The design of reliable protection scheme is one of the major challenges associated with microgrids. This is because of the transition of microgrids between grid-tied and islanded operational modes. This thesis proposes a new Kalman filter (KF)-based microgrid protection scheme. The proposed scheme uses one-end current signal of a distribution line for fault detection and classification. Firstly, the KF is applied on each phase of a three-phase current signal individually to generate residual and total harmonic distortion (THD). Next, the variations in the residuals and THD of each phase are compared with a pre-defined threshold values to detect the occurrence of fault in the microgrid. Since each phase is processed through KF individually, the proposed scheme is inherently phase segregated. The KF is applied to extract the third harmonic components from three-phase current and voltage signals. Then, the KF based reactive power is obtained from the extracted third harmonic component. Finally, the directional properties of the KF-based reactive power (KFBRP) are used to identify the faulty section in the microgrids. Extensive simulation on MATLAB/Simulink software are carried out for both the grid-tied and the islanded modes of operation under radial and meshed topologies. The results show that the proposed scheme provides highly promising results in all testing scenarios without any false tripping and blinding issues.