Frequency regulation at a wind farm using time-varying inertia and droop controls

Wu, Yuan‐Kang; Yang, Wu-Han; Hu, Yi‐Liang; Quoc, Dung Phan

doi:10.1109/icps.2018.8369978

Cited by 10 publications

(4 citation statements)

References 22 publications

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“…Equation ( 23) shows the direct relation between the grid frequency drop ω 0 − ω g and important control parameters in VSG-ISynC control strategy under the most extreme condition, the maximum grid frequency drop ω gmax can be calculated from (23) as 3 (k p_vsg k dc + D vsg ) 2 (24)…”

Section: Stability Analysis Of M-vsg Control Strategy a Quantitative Analysis Of Stabilty Margin And Coefficient Kp_vsgmentioning

confidence: 99%

Stability Enhancement and Direct Speed Control of DFIG Inertia Emulation Control Strategy

Shao

Cai

et al. 2019

IEEE Access

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With the increasing penetration of renewable energy generators in power grid, traditional vector control (VC) strategy for double fed induction generator (DFIG) is unable to provide extra active power support to grid because DIFG inertia is made decoupled from grid frequency fluctuations. To solve this problem, Virtual Synchronous Generator (VSG) control strategy as well as Inertial Synchronization Control (ISynC) strategy are proposed for DFIG rotor side converter (RSC) and grid side converter (GSC) respectively, so that DFIG rotor speed will experience an acceleration or a deceleration process to release or absorb the kinetic energy stored in DFIG wind turbines, which can prevent grid frequency from deep drop or increase. However, VSG-ISynC control strategy has its limitations in that rotor speed may lose its stability when large load is added into power system, at the same time, the secondary frequency drop is serious if rotor speed has decreased lower than the admissible minimum value. To address this issue, a modified VSG (M-VSG) control strategy is proposed by dynamically changing the P-f droop coefficient of conventional VSG control strategy, aiming to expand the stability boundary of DFIG operation. Additionally, an extra rotor speed closed loop is added into VSG control strategy, which can significantly reduce serious frequency secondary drop by controlling rotor speed directly. Simulation and hardware-in-loop (HIL) verification are both carried out in RTDS & GH Bladed co-simulation research platform to verify the effectiveness of proposed M-VSG control strategy.

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Section: Stability Analysis Of M-vsg Control Strategy a Quantitative Analysis Of Stabilty Margin And Coefficient Kp_vsgmentioning

confidence: 99%

Stability Enhancement and Direct Speed Control of DFIG Inertia Emulation Control Strategy

Shao

Cai

et al. 2019

IEEE Access

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“…The IC strategies can be roughly divided into three classifications characterized by the definition of the shape of the power reference: df/dt-based IC, frequency deviation-based IC, and stepwise IC (Morren et al, 2006;Vyver et al, 2016;Li et al,2017;Hu and WU, 2019;Wu et al, 2019;Kheshti et al, 2019;Peng et al, 2020). The df/dt-based IC can emulate the inertia response to support the reduced inertia response.…”

Section: Introductionmentioning

confidence: 99%

Dynamic power-based temporary frequency support scheme for a wind farm

You

Xu²,

Cao³

2022

Front. Energy Res.

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Doubly fed induction generators can participate in frequency support following a disturbance by releasing their rotational energies. However, when regaining the rotor speed, a secondary frequency dip (SFD) tends to produce a sudden output drop. This study suggests a dynamic power-based stepwise inertial control (IC) scheme of a wind power plant for minimizing the SFD while reducing the maximum frequency deviation (MFD), considering the non-negligible wake. To this end, the reference of the output power increases to the torque limit. Afterward, the power reference smoothly decays with the dynamically decreasing incremental power and then automatically switches to the maximum power point tracking operation. The performance of the temporary frequency support with the suggested stepwise IC strategy is investigated with various penetration levels of wind power. Test results demonstrate that the suggested stepwise IC strategy can minimize the SFD and reduce mechanical stresses on the wind turbine during the recovery of the rotor speed while reducing the MFD. Therefore, the suggested stepwise IC strategy secures the dynamic frequency stability of an electric power system dominated by wind power generations.

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“…Electronic converter interfaced variable-speed wind turbine generators (VSWTGs), e.g., doublyfed induction generators (DFIGs), which are the most promising replacement for SGs, are able to provide frequency response functions for sustaining the dynamic system frequency by designing the control strategies (Dreidy and Mokhlis, 2017)− (Wu et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Two-Phase Short-Term Frequency Response Scheme of a DFIG-Based Wind Farm

2021

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The kinetic energy stored in the doubly-fed induction generators (DFIG)-based wind farm can be utilized to sustain the dynamic system frequency. However, difficulties arise in determining the control gain to effectively improve the frequency nadir and smoothly return to the maximum power point tracking (MPPT) operation. This paper addresses a two-phase short-term frequency response (STFR) scheme to boost the frequency nadir and minimize the second drop in the system frequency based on a piecewise control gain. To achieve the first goal, a constant control coefficient, which is determined according to the initial operating conditions of the DFIG-based wind farm, is employed until the frequency nadir produces. To achieve the second goal, the control coefficient, which changes with time, facilitates to smoothly return to the MPPT operation. The effectiveness of the proposed two-phase STFR scheme is verified under various wind power penetration levels, wind speeds, and disturbances. The results reveal that the frequency nadir is improved, and simultaneously, it smoothly returns to the MPPT operation and minimizes the second drop in the system frequency.

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Frequency regulation at a wind farm using time-varying inertia and droop controls

Cited by 10 publications

References 22 publications

Stability Enhancement and Direct Speed Control of DFIG Inertia Emulation Control Strategy

Stability Enhancement and Direct Speed Control of DFIG Inertia Emulation Control Strategy

Dynamic power-based temporary frequency support scheme for a wind farm

Two-Phase Short-Term Frequency Response Scheme of a DFIG-Based Wind Farm

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