Robust power converters for renewable generation systems in future networks with short circuit ratio wide variations
G. Santamaria Martin(1), R.Griñó(2), A. Gil de Muro Zabala(3) 1. Jema Energy S.A, Lasarte-Oria, Gipuzkoa (Spain). 2. Institute of Industrial and Control Engineering (IOC) Universitat Politécnica de Catalunya (UPC). 3. Tecnalia, Basque Research and Technology Alliance (BRTA), Derio, Bizkaia (Spain). 2026-01-20

Abstract

The European Directive (EU) 2018/2001 requeststhe connection of a new renewable inverter-based resources (RIR) but ensuring that the connection point is strong enough to minimize and avoid possible interaction phenomena. Historically, the indicator used to determine the strength of a network has been the Short Circuit Ratio (SCR). Until now, the tendency had been to ensure that the network remained strong enough with High SCR, but another possibility is to ensure that RIR can operate stably and reliably at different SCR values, both high and low. The inverters currently deployed in European power systems use grid following inverter technology (GFI). The main objective of the present work is the redesign of the traditional current regulators of JEMA Energy PV family inverters, based on grid following technology, to guarantee the stability of electrical systems with a variable short-circuit ratio in the range [1÷20]. To achieve this, the current loops of the inverter are redesigned, introducing an additional first-order controller that improves the dynamics of the system and allows stable and efficient behaviour. For validation purposes, the system is analysed under adverse fault scenarios. The results obtained in all cases are satisfactory, but the stability with PLL (phase lock loop) slower than those originally used, is better.

Key words: Renewable power converters, Grid following converters, robustness, SCR, weak and strong grid, fault events, UE 2016/631.

References

[1] Technical criteria for evaluating network strength for integration of electric park modules according to existing
technical literature from REE, February 28, 2019. https://www.esios.ree.es/en/page/connection-networkcodes

[2] M. Orellana and R. Griñó, “Técnicas de control avanzadas para la mejora de la operación de convertidores VSI conectados a la red eléctrica”, PhDThesis, Universitat Politècnica de Catalunya, December 2018
https://upcommons.upc.edu/handle/2117/22820?

[3] BOE-A-2020-8965, pp. 62423-62426. https://www.boe.es/diario_boe/txt.php?id=BOE-A-2020-8965

[4] Norma técnica de supervisión de la conformidad de los módulos de generación de electricidad según el Reglamento UE 2016/63. https://aelec.es/wp-content/uploads/2021/07/20210709-NTS-SEPE-v2.1.pdf