Low-Frequency Converter-Driven Oscillations in Weak Grids: Explanation and Damping Improvement

Autor:	Yingbiao Li, Xi Zhang, Huadong Sun, Guanglu Wu, Bing Zhao, Shiyun Xu, Xiaoxin Zhou, Shanshan Wang, Gen Li, Agusti Egea-Alvarez
Rok vydání:	2021
Předmět:	Physics Phase-locked loop Oscillation Control theory Automatic frequency control Energy Engineering and Power Technology Sensitivity (control systems) Electrical and Electronic Engineering AC power Transfer function Group delay and phase delay
Zdroj:	IEEE Transactions on Power Systems. 36:5944-5947
ISSN:	1558-0679 0885-8950
DOI:	10.1109/tpwrs.2021.3099341
Popis:	Low-frequency oscillations have been reported in several weak-grids-connected voltage-source-converter(VSC) systems. Although efforts have been devoted to understand the parametric and sensitivity impact of the VSC controller gains, a general formulation of the oscillation mechanism is still missing. Using transfer function dynamic modelling approach, we find that the outer loop active power control's bandwidth mainly determines the oscillation frequency. The PLL introduces a large phase lag around the frequency of the PLL bandwidth in weak grids conditions which decreases the oscillation damping. A simple but effective PI+Clegg integrator (CI) compensator is proposed to replace the standard outer loop active power controller compensating the PLL's phase delay and increase the oscillation damping. The results are verified in a real time digital simulator.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::3986f57e68d0b3cba16769c3add21ae0 https://doi.org/10.1109/tpwrs.2021.3099341 Zobrazit plný text záznamu