A New Method for Analysis and Estimation of Microgrid Signals Under Fault Conditions

Accurate phasor estimation under various faulty conditions is one of the most critical issues in the monitoring, protecting, and controlling of a microgrid (MG). This paper presents a new phasor estimation algorithm (PEA) under fault conditions for MG applications. The main features of this method are to accurately phasor estimation of the signal combination of a decaying dc offset, a decaying fundamental frequency component, and harmonics. In this strategy, a Taylor series is replaced by the exponential functions of the fundament frequency and decaying dc offset component. Then, the time constants and the magnitudes of decaying components are estimated by the least square method. The proposed method is explained theoretically, and its performance is demonstrated by simulating various numerical signals in MATLAB and measured signals during fault conditions. The simulation results indicate that the proposed method estimates the dynamic phasor during fault conditions, accurately. Furthermore, a comprehensive comparison with the conventional methods is carried out to show the effectiveness of the proposed algorithm.