An adaptive fault-component-based current differential protection scheme for distribution networks with inverter-based distributed generators

摘要

The high penetration of inverter-based distributed generators (IBDGs) T-connected into distribution networks has changed their structure from single-source networks to multi-source multi-branch networks; therefore, conventional distribution network protection schemes are difficult to apply. To this end, a mathematical model of IBDG fault component current considering the control strategy of IBDG is established, and then, a method for estimating the IBDG fault component current using only electrical information at both terminals of the protected line is proposed. On this basis, an adaptive fault-component-based current differential protection scheme suitable for distribution networks with IBDGs is proposed. The proposed scheme only needs to exchange the electrical information at both terminals of the protected line; that is, it can adapt to multiple IBDGs that are T-connected into the distribution networks, reducing the requirements of multi-terminal protection for communication channels and thus lowering costs. Finally, the effectiveness of the proposed protection scheme is demonstrated in the PSCAD/EMTDC software. The results show that the proposed protection scheme is not affected by the location, capacity of the IBDGs, or the fault type and has a high sensitivity.