Optimal coordinated design of under-frequency load shedding and energy storage systems

P. Santurino, L. Sigrist, A. Ortega, J. Renedo, E. Lobato

Electric Power Systems Research Vol. 211, pp. 108423-1 - 108423-8

Summary:

Under-frequency load shedding (UFLS) is considered a fundamental protection tool against power imbalances in electrical grids, particularly in small island systems. However, load shedding entails a delicate compromise between guaranteeing the stability of the system and disconnecting the lowest amount of load to achieve it. Fast-responding converter-interfaced energy storage systems (ESSs) can help improve such a compromise. In this regard, this paper proposes a methodology for the coordinated design of under-frequency load shedding (UFLS) and fast-responding converter-interfaced energy storage systems (ESSs). UFLS parameters include thresholds for frequency and its rate-of-change, and time settings of each step. ESS control parameters comprise, among others, the emulated inertia and the droop. The proposed coordinated methodology is applied to a real Spanish island power system with a 4 MW/5.6 kWh ultracapacitor (UC). Results show that the proposed methodology is able to significantly reduce the total amount of load shed with respect to the currently implemented UFLS settings and UC control parameters.

Spanish layman's summary:

En este artículo se ajustan simultáneamente los parámetros del control de sistemas de almacenamiento de energía y de las protecciones de subfrecuencia. El ajuste simultánea mejora la operación de sistemas insulares.

English layman's summary:

This paper simultaneously tunes the control parameters of energy storage systems and of the underfrequency protections. The simultaneous tuning improves operation of island power systems.

Keywords: Frequency stability; Under-frequency load shedding; Energy storage systems; Ultracapacitors; Island grids

JCR Impact Factor and WoS quartile: 3,900 - Q2 (2022)

DOI reference: https://doi.org/10.1016/j.epsr.2022.108423

Published on paper: October 2022.

Published on-line: July 2022.

Citation:
P. Santurino, L. Sigrist, A. Ortega, J. Renedo, E. Lobato, Optimal coordinated design of under-frequency load shedding and energy storage systems. Electric Power Systems Research. Vol. 211, pp. 108423-1 - 108423-8, October 2022. [Online: July 2022]