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Vahabzadeh, Taleb

University of British Columbia

Modern power systems are experiencing increasing deployment of power-electronic-interfaced renewable and distributed energy resources (R/DERs), leading to new dynamics and challenges in transient and stability assessment. The reliable design, analysis, and optimum operation of such systems require advanced simulation tools. The detailed switching and dynamic average value models (AVMs) of converters, commonly used for time-domain transient analysis, are computationally expensive and pose interfacing challenges in electromagnetic transient programs (EMT/EMTP), limiting offline and real-time simulations. Furthermore, conducting stability analysis for multi-converter-based systems in the frequency domain using impedance-based modelling (IBM) involves the aggregation of individual converters. This approach results in creating multi-input multi-output (MIMO) transfer matrices with high-order transfer functions, introducing complexities that render this approach impractical. This thesis advances state-of-the-art and develops novel transient and stability analysis tools for the analysis of modern power systems in the time- and frequency-domain. For time-domain transient analysis, this thesis develops an impedance/admittance-based electromagnetic transient (I/ABM-EMT) approach for analyzing large-scale power-electronics-based energy conversion systems. Compared to the traditional EMTP approach with a detailed representation of all switches or the use of AVM for the converters, the developed approach applies IBM to the converter-based resources, which reduces the effective network to be simulated and the size of the overall nodal equation. Moreover, for stability analysis in the frequency-domain, this thesis proposes a numerical recursive aggregation technique that, unlike the more established analytically aggregated modelling, uses a numerical approach to aggregate the MIMO transfer matrices, which avoids some of the challenges of traditional analytical operations. Furthermore, an algorithm is proposed to automate the aggregation of large-scale converter-based systems. The new algorithm is formulated as a recursive process to deal with the typical tree-like structure of distribution systems. Extensive offline and real-time studies demonstrate the superiority of the developed modelling and simulation tools in terms of computational efficiency and accuracy compared to the alternative state-of-the-art approaches.

Text

2024-02-29

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/87492

Electrical and Computer Engineering

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/