Signature-Coordinated Digital Multirelay Protection for Microgrid Systems

• Published in: IEEE transactions on power electronics Vol. 29; no. 9; pp. 4614 - 4623
• Main Author: Saleh, S. A.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.09.2014; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Communication; Connection and protection apparatus; Digital; Digital relays; Distributed generation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electronics; Exact sciences and technology; Faults; Frequencies; Indexes; microgrids; Miscellaneous; Power networks and lines; protection systems; Real time; real-time systems; Testing, measurement, noise and reliability; Time-frequency analysis; Transforms; Transient analysis; Users connections and in door installation; Wavelet; Wavelet analysis; Wavelet transforms; Performance evaluation; Autonomous system; Subband; Distributed power generation; Damage prevention; Protection system; microgrids; Digital protection; Distribution network; Digital relays; Protective device; Connection; Distributed system; Real time; Real time system; protection systems; distributed generation; Electrical network; Wavelet transformation; wavelet analysis; real-time systems; Electric power production; High frequency; Signal analysis; Digital relay; Defect detection
• ISSN: 0885-8993; 1941-0107
• DOI: 10.1109/TPEL.2013.2285978

This paper presents the real-time testing of a digital protection for microgrids operated in utility-connection and stand-alone modes. The tested protection is structured with coordinated digital relays, which are featured with a fault identification based on the wavelet packet transform (WPT). The coordination of the employed digital relays is established based on the second-level high-frequency subbands extracted from the d-q-axis components of the currents flowing through each point of branching. The second-level high-frequency subbands are extracted and parametrized by two sets of WPT coefficients. The first set of WPT coefficients is utilized for identifying faults, while the second set is employed to locate identified faults. The d-q WPT-based digital multirelay protection is realized without time-based coordination, adaptive features, or relay-to-relay communication. Performances of the d-q WPT-based digital multirelay protection are investigated for a laboratory microgrid. Test results demonstrate accurate, fast, reliable, and coordinated responses, along with insensitivity to the mode of operating the microgrid.