**6. Conclusions**

The hosting capacity of power distribution systems for introducing DGs based on PCS such as renewable energy sources is increasing, and the number of rotor-based power plants is being reduced. This tendency makes the stability and power quality in power systems critical, especially in the event of a temporary fault in distribution systems. As a result, the large increase of DG deployment may lead to not only economic damage, but also system operation problems.

To solve these problems, the TFRT method is proposed. That is, at first, it is determined whether a fault in distribution systems is temporary or permanent. Then DG is disconnected for a permanent fault and continues to operate for a temporary fault by applying the proposed TFRT method. It was verified using the PSCAD/EMTDC software package that the TFRT method can control DGs to keep operating even if a temporary fault occurs. Also, it can control current and voltage to prevent damage due to over-/under-voltage and over-current occurred by the reclosing of the CB or recloser.TDC programming tool. proposed e as under/over- voltage occurred.

Finally, it is expected that the proposed TFRT method can improve the reliability and stability of distribution systems and is included in current grid code worldwide through further research.

**Author Contributions:** Validation, J.-S.O.; Investigation, S.-G.J. and D.-K.K.; Writing—original draft preparation, J.-H.L.; Writing—review and editing, J.-E.K.; All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Acknowledgments:** This work was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) gran<sup>t</sup> funded by the Korean governmen<sup>t</sup> (MOTIE) (20181210301470, Development and Proof on the Commercialization of the Broker Service based on Small-scale Distributed Energy Resources).

**Conflicts of Interest:** The authors declare no conflict of interest.
