Work

Quasi Steady-State Frequency

Year: 2025

Type: article

Abstract: Accurate frequency estimation is critical for the control, monitoring and protection of electrical power systems. This paper introduces the novel concept ofQuasi Steady-State (QSS) frequencyas a quantity that fills the gap between stationary and instantaneous frequency. QSS frequency coincides with the fundamental frequency of an AC voltage in any stationary conditions, including unbalanced and non-sinusoidal, and is able to capture the time-varying fundamental frequency in transient conditions. The paper also proposes a metric borrowed from fluid dynamics, namely, the time derivative of the circulation, to define the scope of validity of the QSS frequency. Analytical examples as well as a case study based on a fully-fledged EMT model of the IEEE 39-bus system serve to illustrate, respectively, the properties of the QSS frequency and its behavior in transient conditions.

Source: IEEE Transactions on Circuits and Systems I Regular Papers

DOI: 10.1109/tcsi.2025.3612501

Authors: Joan Gutiérrez-Florensa, Álvaro Ortega, Lukas Sigrist, Federico Milano

Institutions: University College Dublin, Universidad Pontificia Comillas

Language: English

Topic: Power System Optimization and Stability

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $2,645

Funder: Sustainable Energy Authority of Ireland