Evaluation of Passive Islanding Detection of Phase Angle Difference Method in a Three Phase Microgrid System

Abstract

The evolutions of Microgrids with renewable energies have revolutionized the power sector, to meet the additional power demand, along with reducing the pollution levels. These developments have created challenges in the operation and control of Distributed Energy Resources (DERs). The IEEE standards imposed certain limits on parameters like voltage, frequency, %Total Harmonic Distortion (THD %) etc. To make the Microgrid more efficient and robust, the Microgrid is to be designed for its stability during transient operations and must isolate the Microgrid seamlessly from the grid, for symmetrical faults, in less than 2 seconds as per regulations of IEEE and also the Non-Detection zone has to be as minimum as possible, which is less than 15%. In this paper an efficient and reliable passive islanding detection method, Rate of change of phase angle difference (ROCPAD) is used to detect the islanding scenario for symmetrical faults to isolate the Microgrid from the main grid and to be stable during loads connecting and throwing off at PCC. The testing is done in MATLAB as per UL-1741 and the results concluded the conformity of the method. The proposed method is also compared with the widely used Rate of change of frequency method (ROCOF). As this is a passive method, there is no issue with power quality.