Eliminating the Need for a Less Strict Requirement for the Negative-Sequence LVRT Current of Type-III Wind Turbine Generators in the IEEE 2800 Standard

Similar to emerging regional grid codes, the recently approved IEEE 2800 Standard mandates that inverter-based resources (IBRs) generate negative-sequence current during low-voltage ride-through (LVRT) conditions. The 2800 Standard requires that the IBRs' negative-sequence current lead the negative-sequence voltage by 90<inline-formula><tex-math notation="LaTeX">$^\circ$</tex-math></inline-formula>–100<inline-formula><tex-math notation="LaTeX">$^\circ$</tex-math></inline-formula> to emulate synchronous generators and reduce the likelihood of protection malfunction. However, the limitations of existing doubly-fed induction generators (DFIGs) led the Standard to exempt the DFIGs from this requirement and allow a wider range for their negative-sequence current angle. Meanwhile, the 2800 Standard also acknowledged that this exemption had unidentified and potentially negative impacts on protective relays. This paper (i) sheds light on several so-far-unknown DFIG characteristics that impact the angle of the negative-sequence current during LVRT, (ii) reveals the impacts of the above DFIG exemption on relays, and (iii) develops a solution to prevent the need for this exemption in the future revisions of the IEEE 2800 Standard.