A Unified Analytical Method to Quantify Three Types of Fast Frequency Response from Inverter-Based Resources

Shuan Dong, Xin Fang, Jin Tan, Ningchao Gao, Xiaofan Cui, Anderson Hoke

Research output: Contribution to conferencePaper

1 Scopus Citations


With more inverter-based resources (IBRs), our power systems have lower frequency nadirs following N-1 contingencies, and undesired under-frequency load shedding (UFLS) can occur. To address this challenge, IBRs can be programmed to provide at least three types of fast frequency response (FFR), e.g., step response, proportional response (P/f droop response), and derivative response (synthetic inertia). However, these heterogeneous FFR challenge the study of power system frequency dynamics. Thus, this paper develops an analytical frequency nadir prediction method that allows for the consideration of all three potential forms of FFR provided by IBRs. The proposed method provides fast and accurate frequency nadir estimation after N-1 generation tripping contingencies. Our method is grounded on the closed-form solution for the frequency nadir, which is solved from the second-order system frequency response model considering the governor dynamics and three types of FFR. The simulation results in the IEEE 39-bus system with different types of FFR demonstrate that the proposed method provides an accurate and fast prediction of the frequency nadir under various disturbances.
Original languageAmerican English
Number of pages6
StatePublished - 2023
Event22nd Wind and Solar Integration Workshop (WIW 2023) - Copenhagen, Denmark
Duration: 26 Sep 202328 Sep 2023


Conference22nd Wind and Solar Integration Workshop (WIW 2023)
CityCopenhagen, Denmark

NREL Publication Number

  • NREL/CP-5D00-89047


  • fast frequency response
  • frequency nadir
  • inverter-based resources
  • system frequency response model


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