Grid-Forming Control With Current Limitation for MMC Under Unbalanced Fault Ride-Through

Freytes, Julian; Li, Jiaqi; Préville, Guillaume de; Thouvenin, Marc

doi:10.1109/tpwrd.2021.3053148

Cited by 46 publications

(18 citation statements)

References 9 publications

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“…The general control diagram of this method is shown in Figure 8. An example similar to this method can be found in [28], and details about how to estimate the current limit with positive and negative sequence components are in [29].…”

Section: Threshold Virtual Impedance Methods For Current Limitingmentioning

confidence: 99%

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Enhanced TVI for Grid Forming VSC under Unbalanced Faults

Zubiaga

Cardozo²,

Prevost³

et al. 2021

Energies

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With an increasing capacity of inverter-based generation and with a 100% renewable energy power system on the horizon, grid forming converters have the potential to become the prevalent control mode in the grid. Thus, the correct performance of these devices is going to be crucial for system stability and security of supply. Most research related to the grid-forming control is focused on normal operating conditions, although significant effort has been devoted to current limitation strategies to ensure Low Voltage Ride Through (LVRT) capability. However, most contributions usually consider only balanced faults. This paper, proposes a new current limiting method based on the well-known threshold virtual impedance (TVI) that keeps the voltage source behaviour associated to the grid forming (GFM) capability, even when the current limit is reached, while reducing the voltage unbalance according to user-defined settings.

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Section: Threshold Virtual Impedance Methods For Current Limitingmentioning

confidence: 99%

“…Along with the module, the angle of each sequence is also estimated, Equations ( 10) and (11) An example similar to this method can be found in [28], and details about how to estimate the current limit with positive and negative sequence components are in [29].…”

Section: Threshold Virtual Impedance Methods For Current Limitingmentioning

confidence: 99%

Enhanced TVI for Grid Forming VSC under Unbalanced Faults

Zubiaga

Cardozo²,

Prevost³

et al. 2021

Energies

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“…The current flow through the converters in power control is: Substituting (7) and ( 8) into (6) gives:…”

Section: Mathematical Analysismentioning

confidence: 99%

“…Islanded controls are used when converter stations are connected to an AC system with a passive load or with limited generation. They can create an AC voltage source with fixed frequency, amplitude and phase angle at the islanded network [4][5][6][7]. However, the large-scale grid integration of renewable energy sources and power converters may increase the risk of control interactions in power systems.…”

Section: Introductionmentioning

confidence: 99%

Demonstration of Converter Control Interactions in MMC-HVDC Systems

et al. 2022

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Although the control of modular multi-level converters (MMCs) in high-voltage direct-current (HVDC) networks has become a mature subject these days, the potential for adverse interactions between different converter controls remains an under-researched challenge attracting the attention from both academia and industry. Even for point-to-point HVDC links (i.e., simple HVDC systems), converter control interactions may result in the shifting of system operating voltages, increased power losses, and unintended power imbalances at converter stations. To bridge this research gap, the risk of multiple cross-over of control characteristics of MMCs is assessed in this paper through mathematical analysis, computational simulation, and experimental validation. Specifically, the following point-to-point HVDC link configurations are examined: (1) one MMC station equipped with a current versus voltage droop control and the other station equipped with a constant power control; and (2) one MMC station equipped with a power versus voltage droop control and the other station equipped with a constant current control. Design guidelines for droop coefficients are provided to prevent adverse control interactions. A 60-kW MMC test-rig is used to experimentally verify the impact of multiple crossing of control characteristics of the DC system configurations, with results verified through software simulation in MATLAB/Simulink using an open access toolbox. Results show that in operating conditions of 650 V and 50 A (DC voltage and DC current), drifts of 7.7% in the DC voltage and of 10% in the DC current occur due to adverse control interactions under the current versus voltage droop and power control scheme. Similarly, drifts of 7.7% both in the DC voltage and power occur under the power versus voltage droop and current control scheme.

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“…The voltage sags detection to guarantee proper and acceptable response under failures is crucial, given the urgency and importance of quick reactive power assistance and active power limiting. Detecting voltage sag is critical to the overall performance of the FRT capability control during a grid fault to switch between operating modes quickly and adequately [56][57][58][59]. As a result, built-in fault detection algorithms are used to safely disconnect grid-connected inverter-based equipment during grid outages.…”

Section: Introductionmentioning

confidence: 99%

Modeling of Double Stage Photovoltaic Inverter System with Fast Delayed Signal Cancellation for Fault Ride-Through Control Application in Microgrids

Buraimoh

Davidson

2022

Energies

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This research presents a secondary control for a grid-supporting microgrid with photovoltaics sources to guarantee grid code compliance and ancillary services. The secondary control accomplishes the fault ride-through, which implements a delayed signal cancellation (DSC) algorithm for negative sequence detection. Without mode switching, the proposed control strategy meets grid code requirements and ensures voltage regulation at the secondary level, which is active and more salient throughout the transient period of host grid disturbances. This control also ensures a constant supply of the microgrid’s sensitive local load while adhering to grid code requirements. Similarly, active power injection into the main grid is limited by progressively altering the MPPT operating point dependent on the depth of voltage sag to optimize reactive power injection to sustain grid voltage sag. The recommended secondary control is triggered by utilizing the DSC process’s detection algorithm to identify the occurrence of a fault in a tiny fraction of a half-cycle in a grid fault. Consequently, while satisfying microgrid load needs, the devised technique guaranteed that increases in DC-link voltage and AC grid current were controlled. MATLAB Simscape ElectricalTM and OPAL-RT Lab are used to do time-domain simulations of the model using the recommended secondary control systems.

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Grid-Forming Control With Current Limitation for MMC Under Unbalanced Fault Ride-Through

Cited by 46 publications

References 9 publications

Enhanced TVI for Grid Forming VSC under Unbalanced Faults

Enhanced TVI for Grid Forming VSC under Unbalanced Faults

Demonstration of Converter Control Interactions in MMC-HVDC Systems

Modeling of Double Stage Photovoltaic Inverter System with Fast Delayed Signal Cancellation for Fault Ride-Through Control Application in Microgrids

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