Automatic Generation Control with Virtual Synchronous Renewables

Zhang, Weichao; Sheng, Wanxing; Duan, Qing; Huang, Hsiao-Yun; Yan, Xiangwu

doi:10.35833/mpce.2020.000921

Cited by 13 publications

(8 citation statements)

References 29 publications

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“…Wind-turbine (WT) frequency regulation is divided into two stages: frequency support and restoration. To develop the frequency-support capability of the WT, overspeed control [6], [7], pitch angle control [8], [9], virtual synchronous generator control [10], [11], and virtual inertia integrated control (VIIC) [12]- [17] have been proposed. Under normal conditions, the VIIC operates in MPPT mode, releasing the kinetic energy of the WT rotor to provide power support in the frequency-support stage by emulating the inertia and damping of the synchronous generators.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, it is important to develop a more appropriate approach for evaluating the frequency-regulation potential of a WT. After the frequency-support stage, the WT usually starts to restore the rotational speed to avoid uneconomical low rotational speed operation, resulting in a second frequency dip (SFD) and threatening the safety of the power system [11]. Energy-storage strategies [23], [24] and initiative power control [21], [25]- [29] have been proposed to avoid an SFD.…”

Section: Introductionmentioning

confidence: 99%

“…Modular multilevel converter (MMC) is one of the most popular forms of offshore wind power transmission; it has become an important issue to exploit the cooperative frequency regulation potential of MMCs and offshore wind farms [11]. Based on WT frequency-regulation strategies [12] - [22], [25] - [29], the auxiliary frequency control of onshore and offshore VSCs [16], [21], [30], [31] has been developed to implement frequency regulation of wind farms via a single MMC-HVDC system.…”

Section: Introductionmentioning

confidence: 99%

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Frequency Regulation of VSC-MTDC System with Offshore Wind Farms

Liu,

Liu

2024

Journal of Modern Power Systems and Clean Energy

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Frequency regulation of voltage source converterbased multi-terminal high-voltage direct current (VSC-MTDC) system with offshore wind farms enhances the frequency stability by compensating the power for a disturbed AC system. However, it is difficult to reasonably allocate frequency-regulation resources due to a lack of coordination mechanisms between wind farms and the MTDC system. Moreover, it is difficult for the frequency control of the wind farms to manage changes in wind speed; and the risk of wind-turbine stalls is high. Thus, based on the kinetic energy of wind turbines and the power margin of the converters, the frequency-regulation capability of wind turbines is evaluated, and a dynamic frequency-support scheme considering the real-time frequency-support capability of the wind turbines and system frequency evolution is proposed to improve the frequency-support performance. A power adaptation technique at variable wind speeds is developed; the active power in the frequency-support stage and restoration stage is switched according to the wind speed. A hierarchical zoning frequency-regulation scheme is designed to use the frequency-regulation resources of different links in the MTDC system with wind farms. The simulation results show that the novel frequency-regulation strategy maintains frequency stability with wind-speed changes and avoids multiple frequency dips.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Frequency Regulation of VSC-MTDC System with Offshore Wind Farms

Liu,

Liu

2024

Journal of Modern Power Systems and Clean Energy

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“…Moreover, the integration of a significant number of connected distributed generation systems can adversely impact the stability of power systems [ 4 ]. Virtual synchronous generator (VSG) technology has attracted considerable attention from both domestic and international scholars [ 5 , 6 ]. This technology can be used to emulate the external characteristics of traditional generators, endowing grid-connected inverters with rotational inertia and damping characteristics similar to those of conventional generators.…”

Section: Introductionmentioning

confidence: 99%

An Adaptive Virtual Impedance Method for Grid-Connected Current Quality Improvement of a Single-Phase Virtual Synchronous Generator under Distorted Grid Voltage

Zhong

Zhang

Zhu

et al. 2023

Sensors

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The proportion of distributed generation systems in power grids is increasing, leading to the gradual emergence of weak grid characteristics. Moreover, using voltage-sourced grid-connected inverters can enhance the stability of a weak grid. However, due to the presence of background harmonics in weak grids, the grid voltage can cause significant distortions in the grid-connected current, which adversely affects the quality of the grid-connected current. This paper begins by briefly introducing the principle of the virtual synchronous generator (VSG). Then, the output current of the voltage source inverter is analyzed to elucidate the mechanism of harmonic current generation. Considering the distortion in the grid-connected current of the voltage source grid-connected inverter caused by background harmonics in the grid voltage, a harmonic current suppression strategy based on an adaptive virtual harmonic resistor is proposed. The proposed strategy employs a signal separation module based on multiple second-order generalized integrators connected through a cross-feedback network. This module effectively separates the fundamental and harmonic currents from the grid-connected current, extracts the amplitudes of the fundamental and harmonic currents through coordinate transformation, and adaptively adjusts the virtual harmonic resistance magnitude through the negative feedback control of the harmonic content (the ratio of the harmonic current amplitude to the fundamental current amplitude). These measures are used to enhance the quality of the grid-connected current. Additionally, the stability of the system is analyzed using the root locus of the open-loop transfer function. Finally, the effectiveness of the proposed method is validated through a combination of MATLAB/Simulink simulations and experimental results.

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“…from its nominal value whenever load variations in any area occur. This issue is solved by adopting the concept of automatic generation control (AGC) [2]. The term AGC in power system operation is described as the variation of output electrical power from electric generators in a designated area whenever frequency of system, tie-line power, or both varies.…”

mentioning

confidence: 99%

Rank Exponent Method Based Optimal Control of AGC for Two-Area Interconnected Power Systems

Mamta,

Singh,

Waghmare

et al. 2024

IEEE Access

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Automatic generation control (AGC) is employed in power systems to maintain balance between generation and load by adjusting output of generators in real time. Controller continuously monitors system frequency and tie-line power flow by responding to fluctuations in electricity demand and supply and optimizes generator dispatch, reduces power imbalances, and enhances grid stability. This work proposes and solves the issues of the AGC in two-area interconnected power systems by proposing a new approach based on both Jaya algorithm and the rank exponent method. In particular, we design a proportional-integralderivative controller with derivative filtering (PIDm), where the effect of the noise is mitigated by the use of a filter with derivative gain. We propose to build the objective function, to tune the controller's parameters, as the linear combination of three sub-objectives, namely integral of time multiplied absolute error (ITAE) for frequency deviations, tie-line power deviation, and area-control errors (ACEs). The rank method is exploited to evaluate the weights of these sub-objectives, while the final overall objective function is minimized exploiting the Jaya algorithm. The proposed controller's performance is assessed in six different scenarios with load disturbances, and its effectiveness is compared to state-of-art controllers tuned using salp swarm algorithm (SSA), Nelder-Mead simplex (NMS), symbiotic organisms search (SOS), elephant herding optimization (EHO), and Luus-Jaakola (LJ) optimization algorithms. To illustrate the frequency and tie-line power changes, results are also shown, and a statistical study is finally carried out to evaluate the recommended controller's overall effectiveness. Additionally, Friedman rank test as no-parametric statistical analysis is also done in order to evaluate the significance level of optimization algorithms. Our numerical findings evidence that the proposed PIDm controller outperforms other existing optimizationbased controllers in terms of performance and utility, thus proving to be very effective for handling AGC issues in two-are interconnected power systems.INDEX TERMS Rank exponent method, AGC, Jaya optimization, Interconnected power system. I. INTRODUCTIONI N power system, load demand is constantly varying.To meet out the increasing demand for power, singlearea power systems are less reliable. Reliability is the main concern in operation of a power system. To ensure the reliability of power system, distinct areas' generators are interconnected via tie-lines. This type of interconnection is known as interconnected power system (IPS) [1]. In IPS, it is essential to operate all generators at the same frequency in a synchronized manner. The frequency of IPS will deviate VOLUME X, XXXX

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Automatic Generation Control with Virtual Synchronous Renewables

Cited by 13 publications

References 29 publications

Frequency Regulation of VSC-MTDC System with Offshore Wind Farms

Frequency Regulation of VSC-MTDC System with Offshore Wind Farms

An Adaptive Virtual Impedance Method for Grid-Connected Current Quality Improvement of a Single-Phase Virtual Synchronous Generator under Distorted Grid Voltage

Rank Exponent Method Based Optimal Control of AGC for Two-Area Interconnected Power Systems

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