Anti islanding protection for Distributed Generation via open loop voltage and current control technique

Abstract

With the advancement of modern technology, Distributed Generation (DG) systems were introduced to strengthen distribution networks and ensure the delivery of electric power with high quality and reliability, as well as to reduce large losses in electrical energy. The DG systems receive great attention and care from researchers and specialists in the field of electrical energy to supply power with high quality. Despite the benefits of DG systems, they confront significant obstacles that have severe consequences for the system, equipment, maintenance employees, and loads. Unintentional islanding is an abnormal event when a component of the distribution system gets electrically disconnected and the loads are supplied with the energy by the DG only. It is one of the most significant issues that have a large impact on the electrical network, especially in the terms of the protection system. Therefore, anti-islanding protection (AIP) is an important part of the islanding prevention system and detection. Many studies have been conducted in the past to determine islanding using a variety of methodologies based on databases. However, these studies faced various limitations during the implementation of these techniques such as a failure in an accurate time of islanding detection, the detection with the presence of faults, and power quality impacts. In this project, the Open Loop Voltage and Current Control (OLVCC AIP) approach is designed and implemented in the Iraqi radial distribution system that consists of the 3- phase 50 HZ 6-bus of 1200 kVA and 20-bus of 31.5 MVA. The accurate time of unintentional islanding is detected using the OLVCC AIP strategy and compared with the reference measurements of normal operating conditions. The effectiveness of the OLVCC AIP approach is observed in various types of faults in the system. Furthermore, MATLAB/Simulink simulation is used in this project. The OLVCC AIP technique performance is validated by comparing it with the voltage index and line current technique. As a result, the proposed technique effectively detected inadvertent islanding in all scenarios in terms of accurate time without any power quality degradation. The proposed approach improved the performance by 52.88% in identifying the islanding.