Optimal UFLS Settings: An Assessment of Frequency System Response Indicators

C. Adiyabazar, F. Gonzalez-Longatt, M. N. Acosta, J. L. Rueda, P. Palensky

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

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This paper investigates the positive changes in the system frequency response indicators caused by the implementation of a set of optimal settings of an under-frequency load shedding (UFLS) scheme. The optimal UFLS scheme is optimised by minimising the total amount of load shedding and considering the recovery process of the system frequency into its operational values after several losses of generation and satisfies the requirements of the UFLS standard (PRC-006-SERC-02). The idea of implementing the optimal UFLS scheme is to identify how changes the minimum frequency, minimum time, rate of change of frequency and steady-state frequency when the amount of load shedding change. The optimal UFLS scheme formulation starts with identifying the variables to control with the optimisation and its respective bounds. Then, the objective function is formulated in terms of the total load shedding, and finally, the restrictions and requirements of the systems are written as inequality constraints. The optimal UFLS is evaluated in the IEEE 39-bus system. The simulations results demonstrate the suitability of the optimal UFLS to improve the frequency response indicators.
Original languageEnglish
Title of host publication2020 IEEE PES Innovative Smart Grid Technologies Europe (ISGT-Europe)
Number of pages5
Publication statusPublished - 2020
Event10th IEEE PES Innovative Smart Grid Technologies Europe, ISGT-Europe 2020 - Virtual/online event due to COVID-19, Delft, Netherlands
Duration: 26 Oct 202028 Oct 2020
Conference number: 10


Conference10th IEEE PES Innovative Smart Grid Technologies Europe, ISGT-Europe 2020
Abbreviated titleISGT-Europe 2020
OtherVirtual/online event due to COVID-19
Internet address


  • Frequency control
  • Frequency response indicators
  • Optimisation
  • Under-frequency load shedding


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