A novel approach for protection of radial and meshed microgrids

S. Mirsaeidi, X. Dong, D. Tzelepis, C. Booth

Research output: Contribution to conferencePaperpeer-review

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During grid-connected operation mode of microgrids, since the main grid provides a large short-circuit current to the fault point, the protection can be performed by the conventional protective devices, but in islanded mode, fault currents are drastically lower than those of grid-connected mode. Hence, employment of traditional overcurrent-based protective devices in micro-grids is no longer valid and some alternative protection schemes should be developed. This paper presents a micro-grid protection scheme based on positive-sequence component using Phasor Measurement Units (PMUs) and a Central Protection Unit (CPU). The salient feature of the proposed scheme in comparison with the previous works is that it has the ability to protect both radial and meshed micro-grids against different types of faults. Furthermore, since the CPU is capable of updating its pickup values (upstream and downstream equivalent positive-sequence impedances of each line) after the first change in the micro-grid configuration (such as transferring from grid-connected to islanded mode and or disconnection of a line, bus, or DER either in grid-connected mode or in islanded mode), it can protect micro-grid against subsequent faults. In order to verify the effectiveness of the proposed scheme and the CPU, several simulations have been undertaken by using DIgSILENT PowerFactory and MATLAB software packages.


Conference14th International Conference on Developments in Power System Protection
Abbreviated titleDPSP 2018
Country/TerritoryUnited Kingdom
Internet address


  • micro-grid
  • grid-connected mode
  • islanded mode
  • protection scheme
  • positive-sequence component

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