Voltage Actuated Islanding Recognition Method Using Stockwell Transform and Voltage Change Rate

This paper presents a voltage actuated islanding recognition method (VAIRM). VAIRM is formulated by hybrid combination of voltage change rate (VCR) and voltage features computed by processing the voltage signals using Stockwell transform (ST). VCR is computed by differentiating the root mean (RMS) value of voltage. Voltage signal is decomposed using ST to compute the ST median factor (STMF) and STMF change rate (STMFCR). A hybrid islanding recognition indicator (HIRI) is designed to recognize the islanding events considering an islanding recognition threshold (IRTH). Study is performed using an IEEE-13 node test power network (TPN). Proposed method is effective to recognize the islanding event in the presence of wind power generator (WPG), solar power generator (SPG) and both SPG and WPG. VAIRM is also effective to discriminate the operational events such as outage of wind generator, outage of solar generator, load switching on and off events from the islanding events. Performance of VAIRM is not affected by noise and performs better compared to Wavelet packet transform (WPT) and ensemble based method.