Decentralized Grid-Forming Control Strategy and Dynamic Characteristics Analysis of High-Penetration Wind Power Microgrids

Abstract

As wind power generation transitions from centralized development mode to decentralized on-site consumption mode, microgrid (MG) can provide an efficient solution for wind power integration into the distribution network. However, the high-penetration wind power MG is the typical weak power grid system. The traditional wind turbine generator (WTG) participates in system frequency regulation through grid-following current source, which relies on the phase-locked loop for voltage phase synchronization and is unable to provide strong frequency support in weak power grid conditions. To fill this gap, this paper presents a decentralized grid-forming control strategy of highpenetration wind power MG. A wind power adaptive dynamic droop mechanism considering wind energy characteristics and rotor speed dynamic is proposed, cooperating with the implementation of wind maximum power point tracking (MPPT) for economical operation. A detailed small-signal model for voltage source wind power-based system considering electromechanical transients and adaptive droop mechanism is developed. The dominant modes are figured out and the critical control parameters are established and optimized. The proposed wind power adaptive droop mechanism can effectively provide frequency regulation and robust control performance. Theoretical analysis, time-domain simulation results and hardware-in-the-loop experiments under various scenarios verify the feasibility and effectiveness of the proposed strategy.

Grid‐forming control for inverter‐based resources in power systems: A review on its operation, system stability, and prospective

“…Despite this limitation, there are a few approaches using GFL‐based current sources that enable WTGs to participate in the frequency regulation of power systems. This provision is carried out through (1) maintaining power reserve, (2) providing controllable power generation units, and (3) simulating virtual inertia [120].…”

“…VSG, has better impedance characteristics as compared to conventional methods of DFIGURE These studies ignore the characteristics of primary wind energy and the dynamics related to electromechanical transient as these studies are designed for large‐scale wind farms. A decentralized GFM control strategy for an MG with high penetration of DFIG‐based wind power is investigated in [120]. This strategy doesn't rely on PLL and use DFIGs and BESS as GFM‐based voltage source.…”

“…As compared to other articles, Ref. [120] considers the use of GFM control for wind power with high penetration in an autonomous grid, providing continuous voltage and frequency support. In addition to analyzing the rotor speed dynamics and electromechanical transient dynamics, a stability analysis of the full‐order small signal system is also provided.…”

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“…Zhao et al [12] proposed a computationally efficient and accurate reduced order model (ROM) for microgrid stability analysis. Zhao et al [13] proposed a control model for grid-connected wind turbines after they are connected to a microgrid, which provides solution ideas for the control of energy units such as wind turbines in microgrids. An et al [14] proposed a real time adaptive dynamic optimization control strategy based on deep learning.…”