Villahumb

According to IEEE Standard 1547, DGs must be automatically disconnected from the electric power system in the event of faults [7]-[8]. Hence,
DGs will be disconnected faster than the protective device from the faulted circuit using stable islanding method [9]. But this solution would work effectively if the penetration of DGs in the distribution system is low. When the penetration of DG is high, the above technique would reduce reliability as well as the expected benefits of DG. Therefore, by avoiding unnecessary disconnection of DG, benefits of DG can be maximized (Bhalja,2011).

Reference [13] analyzes part of an actual distribution system to identify some more potential cases of malcoordination that depend on size and placement of DG in system. It concludes that, in general, if protection scheme is not changed, the only way to maintain coordination in presence of arbitrary DG penetration is to disconnect all DG instantaneously in case of fault. This would enable the system to regain its radial nature and coordination would withhold. But this would mean that
DG is disconnected even for temporary faults (Brahma, 2004).

[13] S. M. Brahma and A. A. Girgis, “Impact of distributed generation on fuse and relay coordination: analysis and remedies,” in Proc. Int. Assoc.
Sci. Technol. Develop., Clearwater, FL, 2001, pp. 384–389.

Reference [14] discusses this situation in detail and concludes that the coordination in the presence of DG can be achieved with microprocessor-based reclosers available in the market. This recloser has to be made directional toward the downstream side of feeder. But in this case too, all DG downstream of the recloser has to be disconnected before the first reclose takes place to avoid connection without synchronism (Brahma, 2004).

[14] S. M. Brahma and A. A. Girgis, “Microprocessor-based reclosing to coordinate fuse and recloser in a system with high penetration of distributed generation,” in Proc.
IEEE Power