A Reliable Strategy in Order to Islanding Detection Based on Combined Active and Passive Techniques

Abstract

One of the serious concern of grid connected distributed resources is islanding problem. This condition should be prevented due to several reasons concerning such as personnel and equipment safety. This paper investigated a mixed passive and active islanding detection method using energy of rate of change of active power (EROCOAP) and disturbance applying through q-axis of dq-current controller. Reduction of Non detection Zone to as close as possible and keeping the output power quality unchanged in normal condition are main emphasis of the proposed scheme. In addition, this technique can also overcome the problem of setting the detection thresholds inherent in the existing techniques. In this study, we propose to use a hybrid active and passive method for islanding detection. At first, the energy of ROCOAP is calculated for settling time of case study system. If this value becomes higher than threshold value, disturbance is applied to q-axis of current controller. By frequency measurement islanding condition is detected. The simulations results, carried out by MATLAB/Simulink, shows that the proposed method has a small non detection zone. Also, this method is capable of detecting islanding accurately within the minimum standard time.  Index Terms-islanding detection, active techniques, passive technique, NDZ