| Title | Synthetic harmonic distance relaying for inverter-based islanded microgrids |
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| Author | Saleh, K A; Allam, M A |
| Source | IEEE Power and Energy Magazine vol. 8, 2021 p. 258-267, https://doi.org/10.1109/OAJPE.2021.3088876  Open Access |
| Image |  |
| Year | 2021 |
| Alt Series | Natural Resources Canada, Contribution Series 20210534 |
| Publisher | IEEE |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Subjects | engineering geology; Science and Technology |
| Illustrations | schematic representations; graphs; tables; distribution diagrams |
| Program | CanmetENERGY
- Varennes Net Zero Solar Building |
| Released | 2021 06 14 |
| Abstract | Faults in inverter-based islanded microgrids can be a formidable protection challenge due to (i) low fault current magnitudes, (ii) compromised fault current phase angles, and (iii) bidirectional \'1dow
of fault currents. This paper proposes a protection scheme that disregards the fault signals altogether. Instead, it relies on decoupled synthesized signals introduced only during fault conditions. This scheme is achieved by exploiting the existing
inverter-based distributed generation (IBDG) controllers to inject synthetic harmonic voltages and currents. These synthetic signals are measured locally by digital relays in the microgrid to develop a novel synthetic harmonic distance relay (SHDR).
Apart from the utilization of high-order harmonic signals that enhance SHDR reactance reach, further reach improvement is achieved via the introduction of line reactance magni\'1cers (LRMs). Transient studies in PSCAD/EMTDC verify the performance of
the proposed scheme under various faults, contingencies, and different microgrid con\'1cgurations. |
| Summary | (Plain Language Summary, not published)
The concept of "microgrids" has become increasingly important as a viable solution to integrate distributed small-scale renewable energy sources and
energy storage systems into electrical networks. One key advantage of these microgrids is their ability to operate independently from utilities in "islanded" mode, in which they primarily rely on local distributed generators (DGs) for power. However,
protection of islanded microgrids becomes a major challenge, since conventional protection schemes fail in such systems because DGs exhibit fault behaviours different from traditional energy sources. Accordingly, this research proposes a new
protection scheme that exploits the existing DGs to identify faults. The proposed scheme modifies the DGs' controllers, such that they inject unique signals to the electrical network upon fault detection. In addition, to identify the fault location
accurately, the scheme integrates additional circuit elements to the microgrid, which are only activated during faults. Finally, a protection relay is introduced to detect faults and to identify the fault location by measuring and processing the
unique signals injected by the DGs. Simulations have proved the proposed scheme effective under various faults, contingencies, and different microgrid configurations. |
| GEOSCAN ID | 329426 |
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