Fuzzy-Logic-Based Active Protection for Photovoltaic DC Power Plant.

The dc boosting and integration system has been increasingly used in photovoltaic power plants due to its flexible control and excellent performance. The dc boosting and integration system has complex topology and many photovoltaic branches. Because power electronic devices cannot withstand large fault currents, protection with fast operating speed is required. Thus, the starting element has to start quickly and sensitively, and the protective relays must identify the faulty section correctly based on the instantaneous value of the distorted transient fault current. Considering these, the conventional protection carries great potential for disoperation; therefore, a novel active protection is proposed. The starting elements start more sensitively, and the faulty region is correctly distinguished through identifying the fault information generated by active control. The effective fault information is derived from distorted transient instantaneous current data through the fuzzy logic algorithm. Simulation results reveal that the proposed protection can accurately operate within 1 ms when noise is up to 20 dB and transition resistance is up to 500 Ω. [ABSTRACT FROM AUTHOR]