IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, vol.52, no.3, pp.2095-2109, 2016 (SCI-Expanded)
This paper presents the development and performance evaluation of a digital protection for interconnected distributed generation units (DGUs). The developed protection detects and responds to transient disturbances (fault and non-fault conditions) based on the magnitudes and phases of the high frequency sub-band contents, which are extracted from the d − q axis components of the currents flowing through the point-of-common-coupling (PCC). These magnitudes and phases are extracted by 6 phaselet frames that are realized by a modulated filter bank that is composed of 6 digital high pass filters (HPFs). The coefficients of HPFs are determined by bi-orthogonal phaselet basis functions. Extracted magnitudes and phases of the high frequency sub-band contents of PCC d − q axis current components provide signature information for accurate detection and identification of faults. The performance of phaselet frames-based digital protection is experimentally tested for two wind energy conversion systems and a photovoltaic system under different fault and non-fault conditions. Test results demonstrate reliable and timely responses, along with negligible sensitivity to the type and control of DGUs, type and location of faults, and loading levels.