Current Actuated Islanding Detection Method Using Stockwell Transform and Current Change Rate

This paper presents a current actuated islanding detection method (CAIDM). CAIDM is formulated by hybrid combination of current change rate (CCR) and features extracted from current using Stockwell transform (ST). Root mean (RMS) value of current is differentiated with respect to time to compute CCR. A ST current median factor (STCMF) and a STCMF change rate (STCMFCR) are computted by processing the current signal using ST. The CCR, STCMF and STCMFCR are used to design current actuated hybrid islanding detection index (CAHIDI). Islanding events are detected by comparing the peak value of CARIDI with the current actuated islanding detection threshold (CAIDTH). Study is performed using a test power grid (TPG) which is realized using an IEEE-13 node network. Designed CAIDM is effective to detect the islanding event with wind generator (WG), solar generator (SG) and both SG and WG. CAIDM effectively discriminates the islanding events from operational conditions such as wind outage, solar outage, load switching on and off. Performance of CAIDM is not affected by noise and performs better compared to Wavelet packet transform (WPT) and ensemble based method.