scholarly journals Dynamic Frequency Support from a DFIG-Based Wind Turbine Generator via Virtual Inertia Control

2020 ◽  
Vol 10 (10) ◽  
pp. 3376 ◽  
Author(s):  
Dejian Yang ◽  
Enshu Jin ◽  
Jiahan You ◽  
Liang Hua

As the penetrated level of wind in power grids increases, the online system inertia becomes weak. Doubly-fed induction generator (DFIG)-based wind turbine generators (WTGs) are required to provide virtual inertia response to support system frequency. The present inertia control strategy with fixed control gain is not suitable and may cause stall of the DFIG-based WTG, as the virtual inertia response potential from the DFIG-based WTG is different with various wind speed conditions. This paper addresses a virtual inertia control method for the DFIG-based WTGs to improve the system frequency stability without causing stalling of the wind turbine for various wind speed conditions. The effectiveness of the proposed virtual inertia control method is investigated in a small system embedded with the DFIG-based WTG. Results demonstrate that the proposed virtual inertia strategy improves the frequency stability without causing the rotor speed security issue. Thus, the proposed control strategy can secure the dynamic system frequency security of power systems under the scenarios of full and partial loads, and, consequently, the proposed method provides a promising solution of ancillary services to power systems.

Author(s):  
Wang Yin-Sha ◽  
Li Wen-Yi ◽  
Li Zhi-Wen

Background: With the large-scale Doubly Fed Induction Generator (DFIG) wind turbine integrated into the power system, the DFIG inertia response of the wind turbine should be provided. Also, the frequency response should be similar to the conventional generation technologies. This paper investigated the influence of frequency response term and wind speed conditions on system frequency control. Methods: The specific operating conditions of four control strategies, including inertia control, droop control, over speed control and pitch angle control were researched in this paper. Multi-factor coordinated frequency control strategy of DFIG wind turbine was established based on the above researches. The strategy was composed of wind speed ranging from low to high. Results: According to the simulation results, the DFIG wind turbine, which was based on multifactor coordinated frequency control strategy, could respond to the system’s frequency change of power grid, effectively. Conclusion: It helps system frequency return to stable states better and faster than DFIG wind turbine and also could reduce the fluctuation of system frequency.


Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3902 ◽  
Author(s):  
Thongchart Kerdphol ◽  
Masayuki Watanabe ◽  
Yasunori Mitani ◽  
Veena Phunpeng

To integrate renewable energy into microgrids with a favorable inertia property, a virtual inertia control application is needed. Considering the inertia emulation capabilities, insufficient emulation of inertia power due to the lower and short-term power of storage systems could significantly cause system instability and failure. To enhance such capability, this paper applies a virtual inertia control topology to the superconducting magnetic energy storage (SMES) technology. The SMES-based virtual inertia control system is implemented in a microgrid with renewables to emulate sufficient inertia power and maintain good system frequency stability. The efficacy and control performance of the proposed control method are compared with those of the traditional virtual inertia control system. Simulation results show that the shortage of system inertia due to renewable penetration is properly compensated by the proposed control method, improving system frequency stability and maintaining the robustness of system operations.


Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1067
Author(s):  
Youming Cai ◽  
Zheng Li ◽  
Xu Cai

It is important to reduce the impact of the high penetration of wind power into the electricity supply for the purposes of the security and stability of the power grid. As such, the inertia capability of wind farms has become an observation index. The existing control modes cannot guarantee the wind turbine to respond to the frequency variation of the grid, hence, it may lead to frequency instability as the penetration of wind power gets much higher. For the stability of the power grid, a simple and applicable method is to realize inertia response by controlling wind farms based on a high-speed communication network. Thus, with the consideration of the inertia released by a wind turbine at its different operating points, the inertia control mechanism of a doubly-fed wind turbine is analyzed firstly in this paper. The optimal exit point of inertia control is discussed. Then, an active power control strategy for wind farms is proposed to reserve the maximum inertia under a given power output constraint. Furthermore, turbines in a wind farm are grouped depending on their inertia capabilities, and a wind farm inertia control strategy for reasonable extraction of inertia is then presented. Finally, the effectiveness of the proposed control strategy is verified by simulation on the RT-LAB (11.3.3, OPAL-RT TECHNOLOGIES, Montreal, Quebec, Canada) platform with detailed models of the wind farm.


Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4152
Author(s):  
Soroush Oshnoei ◽  
Mohammadreza Aghamohammadi ◽  
Siavash Oshnoei ◽  
Arman Oshnoei ◽  
Behnam Mohammadi-Ivatloo

Nowadays, the renewable energy sources in microgrids (MGs) have high participation to supply the consumer’s demand. In such MGs, the problems such as the system frequency stability, inertia, and damping reduction are threatened. To overcome this challenge, employing the virtual inertia control (VIC) concept in the MG structure could be considered as a viable solution to improve the system frequency response. Hence, this work proposes a novel modeling for VIC in an islanded MG that provides simultaneous emulation of the primary frequency control, virtual inertia, and damping. To show the efficiency of the proposed technique, a comparison is made between the dynamic performance of the proposed VIC and conventional VIC under different scenarios. The results indicate that the proposed VIC presents superior frequency performance in comparison with conventional VIC. In addition to VIC modeling, a new cascade controller based on three-degrees of freedom and fractional-order controllers (FOCs) is proposed as an MG secondary controller. The effectiveness of the proposed controller is compared to tilt-integral-derivative and FO proportional-integral-derivative controllers. The Squirrel search algorithm is utilized to obtain the optimal coefficients of the controllers. The results demonstrate that the proposed controller improves the MG frequency performance over other controllers. Eventually, the sensitivity analysis is performed to investigate the robustness of the proposed controller in the face of the variations of the parameters.


2021 ◽  
pp. 014459872110215
Author(s):  
Shuanbao Niu ◽  
Linan Qu ◽  
Hsiung-Cheng Lin ◽  
Wanliang Fang

The high-level penetration of intermittent renewable power generation may limit power system inertia, resulting in system frequency instability in increasing power converter-based energy sources. To resolve this problem, virtual inertia control using distributed gray wolf optimization (DGWO) method in a synchronous generator is simulated under a distinct output fluctuation condition. First, the DGWO algorithm was established to achieve a local and global balance solution, and standard test functions were employed to verify the model convergence. Second, the key parameters that determine the effect of the virtual inertia controller in the power grid were analyzed. A DGWO-based optimization strategy to stabilize inertia was also developed. Finally, simulation results using step and random loads under a high permeability level are provided to verify the effectiveness of the proposed model. In the step load disturbance, the system can recover from the disturbance point to the stable point after 3 s under the regulation of the proposed control strategy, which is reduced by 18 s compared with the traditional control method. In the random load test, it takes only 12 s, 63 s less than the traditional one. Accordingly, the power system frequency can be stabilized more quickly from a disturbance state to a stable stage.


Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5572
Author(s):  
Tai Li ◽  
Leqiu Wang ◽  
Yanbo Wang ◽  
Guohai Liu ◽  
Zhiyu Zhu ◽  
...  

This paper presents a data-driven virtual inertia control method for doubly fed induction generator (DFIG)-based wind turbine to provide inertia support in the presence of frequency events. The Markov parameters of the system are first obtained by monitoring the grid frequency and system operation state. Then, a data-driven state observer is developed to evaluate the state vector of the optimal controller. Furthermore, the optimal controller of the inertia emulation system is developed through the closed solution of the differential Riccati equation. Moreover, a differential Riccati equation with self-correction capability is developed to enhance the anti-noise ability to reject noise interference in frequency measurement process. Finally, the simulation verification was performed in Matlab/Simulink to validate the effectiveness of the proposed control strategy. Simulation results showed that the proposed virtual inertia controller can adaptively tune control parameters online to provide transient inertia supports for the power grid by releasing the kinetic energy, so as to improve the robustness and anti-interference ability of the control system of the wind power system.


2014 ◽  
Vol 1070-1072 ◽  
pp. 228-232
Author(s):  
Xiao Ying Zhang ◽  
Si Wen Li

With many grid-connected wind farms of Doubly-fed Induction Generator (DFIG) type taking the palce of conventional synchronous generators, the frequency control ability of the system will decrease. But the existing control strategy based on maximum wind power tracking of DFIG can not response to the deviation of the system frequency. This paper proposes a new hybrid frequency control strategy based on the research of the frequency response to the doubly fed induction wind turbine curves switching inertia control loop and the ability for the pitch angle control participating in the system primary frequency modulation. The strategy reduces the initial rate of change and the steady state error of system frequency with the combined action of the curves switching inertial control and pitch frequency control. Finally, the simulation results of the two areas with four generators validate the effectiveness of the strategy.


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