Fuzzy Logic Controller Based Hybrid Anti Islanding Protection Scheme for Distributed Generators

In this research work, a fuzzy logic controller is designed and implemented for small signal stability analysis and anti-islanding protection on the CEGRE LV system. An activated oscillatory disturbance-type signal injection is required in the algorithm. This signal, which contains a considerably low value, is injected via the current administering loop alongside the straightforward axis of the converting devices in a contemporaneously revolving reference frame. Initially, the devised algorithm incorporates the voltage superimposition of the d-axis. The control topology consists of a proportional-integral controller, which has a slower response time. The provision of an early trip signal and effective islanding detection are essential. Additionally, it is necessary to dampen the oscillations as quickly as possible to prevent instability. Since the introduction of a disturbance signal injects harmonics, the overall harmonic distortion should be minimized. To address these issues, a fuzzy logic controller is employed. The fuzzy logic controller provides an earlier trip signal to the system than the proportional-integral controller, thereby improving small signal stability issues. The system performance is discussed in three cases: zero power mismatch, varying loads, and unbalanced conditions. The simulation results of this proposed method are evaluated using MATLAB software.