Detection of DG-islanding employing decision boundary of polarization ellipse parameters

Abstract This article presents a mathematical equations-based approach for islanding detection of distributed generations (DGs). To develop the proposed method, first, a set of mathematical expressions, characterizing the dynamics of electrical quantities during islanding situations, are selected; the quantities are: deviation of rotor angle, frequency and rate-of-change-of-frequency (RoCoF). Second, these electrical quantities are transformed into three-dimensional (3D) Polarization Ellipse (PE) domain, which yields five parameters, namely, azimuth, elevation, tilt angles, semi-minor and semi-major axes. Finally, an equation of decision boundary (DB) is developed to classify between the islanding events and non-islanding incidents. An extensive assessment of the proposed method is carried out considering the critical test cases which include surplus or shortage of real/reactive power mismatch situations that may exist during islanding. The presence of different load-types, with various quality factors, is also accounted for the test. A large number of islanding events and non-islanding disturbances, such as, capacitor switching, load switching, temporary faults, etc., are simulated in real-time using the model of a practical distribution network developed in Opal-RT digital platform. The proposed approach is critically assessed using F-measure technique and the assessment emphasize the selection of the method as a potential tool for detection of DG-islanding.