Evaluation of current limiting methods for grid forming inverters in medium voltage microgrids

Gkountaras, Aris; Dieckerhoff, Sibylle; Sezi, Tevfik

doi:10.1109/ecce.2015.7309831

Cited by 58 publications

(37 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…After the real power, reactive power, and peak voltage are calculated a droop control is performed to using the equation 3.5, where m p is the droop power-frequency char- A virtual impedance current limiting scheme discussed in [17] was used to limit the currents at 2 pu. The virtual impedance method is an alternative to the current reference limitation used in the grid following inverter.…”

Section: Grid-forming Inverter Modelmentioning

confidence: 99%

Adaptive Protection Scheme for a Real-World Microgrid with 100% Inverter-Based Resources

Patel

Brahma

Hernández-Alvídrez

et al. 2020

2020 IEEE Kansas Power and Energy Conference (KPEC)

View full text Add to dashboard Cite

The integration of renewable and distributed energy resources to the electric power system is expected to increase, especially at the distribution level. As more renewable generation connects to distribution systems, it is imminent that existing distribution feeders will be converted to microgrids. Microgrids are systems, typically at distribution voltage level, sustained by distributed and often renewable sources, that can operate in grid-connected and islanded modes. Microgrids offer resilience by providing the flexibility of supporting the grid in normal operation and operating as self-sustained islands when the grid is disconnected.

show abstract

Section: Grid-forming Inverter Modelmentioning

confidence: 99%

Adaptive Protection Scheme for a Real-World Microgrid with 100% Inverter-Based Resources

Patel

Brahma

Hernández-Alvídrez

et al. 2020

2020 IEEE Kansas Power and Energy Conference (KPEC)

View full text Add to dashboard Cite

show abstract

“…However, this will cause wind-up in the outer power loops, which can lead to instability [17]. To circumvent this, several researchers propose the use of virtual resistors, either linear [23] or nonlinear [24] to reduce the converter voltage reference. Also, the influence of a virtual impedance structure on the current limitation is analyzed in [25].…”

Section: Introductionmentioning

confidence: 99%

“…As disclosed, the current limitation is largely depending on the fault location and the selected virtual impedance, which may limit its usefulness in practice as the maximum converter current is desired to be utilized during any fault condition. To that end, the virtual impedance concept may cause problems in parallel operation [24]. In [26], both limitations of the inner current reference and voltage reference reduction using the virtual impedance concept are conducted.…”

Section: Introductionmentioning

confidence: 99%

Current Limiting Control With Enhanced Dynamics of Grid-Forming Converters During Fault Conditions

Taul

Wang

Davari

et al. 2020

IEEE J. Emerg. Sel. Topics Power Electron.

238

204

View full text Add to dashboard Cite

With an increasing capacity in the converter-based generation to the modern power system, a growing demand for such systems to be more grid-friendly has emerged. Consequently, grid-forming converters have been proposed as a promising solution as they are compatible with the conventional synchronousmachine-based power system. However, most research focuses on the grid-forming control during normal operating conditions without considering the fundamental distinction between a gridforming converter and a synchronous machine when considering its short-circuit capability. The current limitation of grid-forming converters during fault conditions is not well described in the available literature and present solutions often aim to switch the control structure to a grid-following structure during the fault. Yet, for a future converter-based power system with no or little integration of synchronous machines, the converters need to preserve their voltage-mode characteristics and be robust toward weak-grid conditions. To address this issue, this article discusses the fundamental issue of grid-forming converter control during grid fault conditions and proposes a fault-mode controller which keeps the voltage-mode characteristics of the grid-forming structure while simultaneously limiting the converter currents to an admissible value. The proposed method is evaluated in a detailed simulation model and verified through an experimental test setup.

show abstract

“…For the FRT capability enhancement of a VSC controlled as a VSM, the researchers tend to build a VSM structure with an inner positive sequence Current Control (CC) loop [13][14][15][16][17][18][19][20][21][22][23], or positive and negative (pn) sequence controllers [18,24]. In addition to the use of the current loop, some ancillary controllers have been used to enhance the FRT performance such as virtual impedance [13,15,17,19,20,[25][26][27], current reference saturation [18,[28][29][30][31], and some structures merging both techniques [14,16]. However, some authors reported instabilities regarding the virtual impedance [28,29], and the current reference saturation [20,32].…”

Section: Introductionmentioning

confidence: 99%

“…In addition to the use of the current loop, some ancillary controllers have been used to enhance the FRT performance such as virtual impedance [13,15,17,19,20,[25][26][27], current reference saturation [18,[28][29][30][31], and some structures merging both techniques [14,16]. However, some authors reported instabilities regarding the virtual impedance [28,29], and the current reference saturation [20,32]. The authors in [33] reported that an inner CC loop within a VSM structure requires careful tuning to avoid instability, especially for low switching frequency.…”

Section: Introductionmentioning

confidence: 99%

New Fault Detection Algorithm for an Improved Dual VSM Control Structure With FRT Capability

Abdel-Rahim¹,

Smailes

Ahmed

et al. 2021

IEEE Access

View full text Add to dashboard Cite

Grid forming converters are a promising solution to enhance the stability of electrical networks with a high penetration of renewable generation. Virtual Synchronous Machines (VSM) are a particular type of grid forming converter, which can be implemented without an inner Current Control (CC) loop. This VSM implementation can provide a better inertial response than other grid forming structures with an inner CC. However, it cannot limit the current through the converter during a fault. A standard solution uses a VSM as the primary controller with a conventional inner CC acting as a backup controller during fault conditions, referred to here as a Dual VSM control structure. The switching action between the primary and the backup controllers is dependent on an accurate Fault Detection Algorithm (FDA). The conventional FDA mentioned in the literature has limitations in particular but not uncommon scenarios. The article shows the limitations of the conventional FDA in weak grids and unbalanced conditions and introduces a new FDA with improved performance. Two types of sensitivity analysis are used to study the dynamics of the proposed control approach. The First is the sensitivity of the proposed control structure to different fault locations in strong and weak grids. The Second is the sensitivity of the controller response to changing controller parameters. The second analysis is introduced as a reference for tuning and improvement of the control structure introduced.

show abstract

Evaluation of current limiting methods for grid forming inverters in medium voltage microgrids

Cited by 58 publications

References 12 publications

Adaptive Protection Scheme for a Real-World Microgrid with 100% Inverter-Based Resources

Adaptive Protection Scheme for a Real-World Microgrid with 100% Inverter-Based Resources

Current Limiting Control With Enhanced Dynamics of Grid-Forming Converters During Fault Conditions

New Fault Detection Algorithm for an Improved Dual VSM Control Structure With FRT Capability

Contact Info

Product

Resources

About