Probabilistic Analysis of DG Anti-Islanding Protection Security Against Momentary Short-Circuits in Distribution Grids

The islanding protection schemes are used to disconnect distributed generators as soon as possible when an islanding event occurs. Moreover, the protection needs to be secure and not act for events other than islanding, such as short-circuit, load switching or normal fluctuations in the grid voltage and frequency. Recent events have raised concerns about the safety of the protection scheme and the IEEE 1547-2018 standard established ride-through requirements, presenting recommendations about the disconnection of distributed generators in case of excursions of the system’s electrical quantities. Therefore, this paper presents a probabilistic analysis of frequency, rate of change of frequency and fast rate of change of frequency protection security in the occurrence of momentary short-circuit events in the distribution system. The results have shown that the risk of undesired operation is significant, but adopting strategies such as time delay settings and undervoltage block function, the global risk can be reduced from 98.78% to 4.51%, considering the simultaneous operation of the three passive techniques.