Current-Constrained Power-Angle Characterization Method for Transient Stability Analysis of Grid-Forming Voltage Source Converters

Zhang, Yu; Zhang, Chen; Yang, Renxin; Molinas, Marta; Cai, Xu

doi:10.1109/tec.2023.3236620

Cited by 23 publications

(7 citation statements)

References 28 publications

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“…If the initial state and trajectory of the system deviate from this domain, the risk of transient instability becomes imminent. Therefore, the domain of attraction underscores the system's capability to counteract disturbances, serving as an indispensable index for evaluating system stability [25,33]. Depicted in Figure 7 are the basins of attraction for the SRF-PLL and three additional filters within the PLL, calculated using the ode45 algorithm and parameters specified in Section 4.…”

Section: Estimation Of Attraction Domainsmentioning

confidence: 99%

“…Additionally, reference [24] visually depicted transient instability phenomena without analytical tools, utilizing numerical solutions of first and second-order nonlinear system equations to graph phase trajectories. Moreover, reference [25] formulated an analytical Lyapunov energy function, deriving a more conservative stability region. Furthermore, reference [26] investigated the interaction between the current control and the PLL loop, devising a more intricate QSLS model to scrutinize transient synchronization stability.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of Phase-Locked Loop Filter Delay on Transient Stability of Grid-Following Converters

Zhang,

Chen,

2024

Electronics

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To ensure precise phase estimation within the q-axis of the phase-locked loop (PLL), integrating a filter into the q-axis loop is essential to mitigate grid-voltage harmonics. Nevertheless, the intrinsic delay characteristics of this filter impede PLL synchronization during significant grid disturbances. This study begins by developing mathematical models for three types of filters—moving-average filter (MAF) for eliminating odd harmonic components, dq-frame cascaded delayed signal cancellation (dqCDSC) filter, and notch filter (NF). Following the reduction in filter orders, a third-order nonlinear large-signal model of the PLL, incorporating an additional q-axis internal filter, is formulated. Using phase plane analysis, this study investigates the transient synchronism of the grid-following converter (GFL) and explores the influence of delay time constants from the three PLL filters on its behavior while delineating the boundaries of their basins of attraction. Theoretical findings indicate that, relative to the traditional SRF-PLL, incorporating an internal filter into the PLL compromises the transient synchronous stability of GFL. Specifically, greater filter delay time constants exacerbate the GFL’s vulnerability to transient instability amid substantial grid disturbances. Hence, careful consideration is essential when using MAF-PLL and NF-PLL in situations demanding high synchronization stability. The theoretical analyses are validated using Matlab/Simulink to verify their accuracy.

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Section: Estimation Of Attraction Domainsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Analysis of Phase-Locked Loop Filter Delay on Transient Stability of Grid-Following Converters

Zhang,

Chen,

2024

Electronics

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“…The VSG model consists of the active power control loop (APCL) and the reactive power control loop (RPCL), as shown in Formulas ( 1) and (2), respectively. design method, which not only enhances the frequency stability and transient stability but also has better dynamic performance, which makes up for the shortcomings of [27][28][29][30][31].…”

Section: Main Circuit and Vsg Modelmentioning

confidence: 99%

“…For the VSG control with an integral reactive power loop, the transient stability and frequency stability can be achieved simultaneously by jointly adjusting the inertia and the voltage regulation coefficient [13], but there is a parameter design problem as in [30]. A quantitative parameter design method considering both transient stability and frequency stability is proposed, but only the specific voltage drop is considered [31]. In general, although the above research takes into account both transient stability and frequency stability, there are still some shortcomings to be further studied.…”

Section: Introductionmentioning

confidence: 99%

A Method to Improve Both Frequency Stability and Transient Stability of Virtual Synchronous Generators during Grid Faults

Yang,

Tu,

Xiao

et al. 2024

Sustainability

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Transient stability and frequency stability of virtual synchronous generator (VSG)-controlled converters during grid faults are critical for the stable operation of high-share renewable energy power systems. However, the existing transient stability methods often overlook the consideration of frequency stability. This paper presents a method to improve both frequency stability and transient stability of VSGs during grid faults. The influence mechanism of inertia and damping on transient stability and frequency stability is comprehensively analyzed under two types of faults, with or without stable equilibrium points. To address the conflict between frequency stability and transient stability of VSGs with large inertia under the first type of fault, an improved VSG control with angular frequency deviation feedback is proposed. The transient response of this control method is analyzed using small-signal and large-signal models. Furthermore, to achieve optimal dynamic performance, this improved VSG control introduces the optimal damping ratio and presents a parameter design method. Finally, the correctness of the proposed method and its theoretical analysis is verified through experimental results.

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“…Although the control structures of the GFM-PGC are different, they all have the ability to establish AC-side output voltages without relying on grid voltage [18][19][20]. As a consequence, GFM-PGC systems can provide inertial and damping support for power electronic power systems, which is the reason GFM-PGC systems have been receiving widespread attention [21,22].…”

Section: Introductionmentioning

confidence: 99%

Transient Synchronous Stability Analysis of Grid-Forming Photovoltaic Grid-Connected Inverters during Asymmetrical Grid Faults

He,

Yao,

et al. 2024

Energies

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Compared with the traditional grid-following photovoltaic grid-connected converter (GFL-PGC), the grid-forming photovoltaic grid-connected converter (GFM-PGC) can provide voltage and frequency support for power systems, which can effectively enhance the stability of power electronic power systems. Consequently, GFM-PGCs have attracted great attention in recent years. When an asymmetrical short-circuit fault occurs in the power grid, GFM-PGC systems may experience transient instability, which has been less studied so far. In this paper, a GFM-PGC system is investigated under asymmetrical short-circuit fault conditions. A novel Q-V droop control structure is proposed by improving the traditional droop control. The proposed control structure enables the system to accurately control the positive- and negative-sequence reactive current without switching the control strategy during the low-voltage ride-through (LVRT) period so that it can meet the requirements of the renewable energy grid code. In addition, a dual-loop control structure model of positive- and negative-sequence voltage and current is established for the GFM-PGC system under asymmetrical short-circuit fault conditions. Based on the symmetrical component method, the composite sequence network of the system is obtained under asymmetrical short-circuit fault conditions, and positive- and negative-sequence power-angle characteristic curves are analyzed. The influence law of system parameters on the transient synchronous stability of positive- and negative-sequence systems is quantitatively analyzed through the equal area criterion. Finally, the correctness of the theoretical analysis is verified by simulation and hardware-in-the-loop experiments.

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Current-Constrained Power-Angle Characterization Method for Transient Stability Analysis of Grid-Forming Voltage Source Converters

Cited by 23 publications

References 28 publications

Analysis of Phase-Locked Loop Filter Delay on Transient Stability of Grid-Following Converters

Analysis of Phase-Locked Loop Filter Delay on Transient Stability of Grid-Following Converters

A Method to Improve Both Frequency Stability and Transient Stability of Virtual Synchronous Generators during Grid Faults

Transient Synchronous Stability Analysis of Grid-Forming Photovoltaic Grid-Connected Inverters during Asymmetrical Grid Faults

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