A novel method for voltage support control under unbalanced grid faults and grid harmonic voltage disturbances

Dai, Zhiyong; Lin, Hui; Yin, Hang; Qiu, Yanan

doi:10.1049/iet-pel.2014.0618

Cited by 20 publications

(19 citation statements)

References 44 publications

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“…Phase Currents to Symmetric Sequence Currents Proposition 2. Let × ϕ be the rotation angle that translates the optimal active I px and reactive I qx phase currents in (17) and (18) to the symmetric sequence counterparts I p and I q . Under such consideration the active and reactive current references in (7) and (8), being the optimal solution to (10), are…”

Section: A Maximization Of the Lowest Phasementioning

confidence: 99%

Control Strategy for Distribution Generation Inverters to Maximize the Voltage Support in the Lowest Phase During Voltage Sags

Camacho

Castilla

Miret

et al. 2018

IEEE Trans. Ind. Electron.

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Voltage sags are considered one of the worst perturbations in power systems. Distributed generation power facilities are allowed to disconnect from the grid during grid faults whenever the voltage is below a certain threshold. During these severe contingencies, a cascade disconnection could start, yielding to a blackout. To minimize the risk of a power outage, inverter-based distributedgeneration systems can help to support the grid by appropriately selecting the control objective. Which control strategy performs better when supporting the grid voltage is a complex decision that depends on many variables. This paper presents a control scheme that implements a smart and simple strategy to support the fault: the maximum voltage support for the lowest phase voltage. Therefore, the faulted phase that is more affected by the sag can be better supported since this phase voltage increases as much as possible, reducing the risk of under-voltage disconnection. The proposed controller has the following features: a) maximizes the voltage in the lowest phase, b) injects the maximum rated current of the inverter, and c) balances the active and reactive power references to deal with resistive and inductive grids. The control proposal is validated by means of experimental results in a laboratory prototype.

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Section: A Maximization Of the Lowest Phasementioning

confidence: 99%

Control Strategy for Distribution Generation Inverters to Maximize the Voltage Support in the Lowest Phase During Voltage Sags

Camacho

Castilla

Miret

et al. 2018

IEEE Trans. Ind. Electron.

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show abstract

“…The common method for PQD detection is to perform a frequency spectrum analysis on the power distribution signal [6][7][8][9][10][11], however, this method does not provide information on frequency distribution through time. On the other hand, there are few methodologies that consider time-frequency analysis allowing the detection and classification of two or more PQD [12][13][14][15][16][17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

EMD-Based Feature Extraction for Power Quality Disturbance Classification Using Moments

et al. 2016

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Abstract:In electric power systems, there are always power quality disturbances (PQDs). Usually, noise contamination interferes with their detection and classification. Common methods perform frequency or time-frequency analyses on the power distribution signal for detecting and classifying a limited number of PQDs with some difficulties at low signal-to-noise ratio (SNR). In this regard, recently proposed methodologies for PQD detection estimate several parameters and apply distinct signal processing techniques to improve the detection of PQD. In this work, a novel methodology that merges empirical mode decomposition (EMD), the moments of a random variable, and an artificial neural network (ANN) is proposed for detecting and classifying different PQD. The proposed method estimates skewness, kurtosis, and Shannon entropy from the EMD of one-phase voltage/current signal. Then, an ANN is in charge of classifying the input signal into one of nine different classes for PQD, receiving these parameters as inputs. The effectiveness of the proposed method was verified through computer simulations and experimentation with real data. Obtained results demonstrate its high effectiveness reaching an outstanding 100% of accuracy in detecting and classifying all treated PQD through a few number of parameters, outperforming most of previously proposed approaches.

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“…An imbalance can be produced by a shift between the phases of a three-phase system or by differences between its voltage amplitudes. This last case is the most frequent and is produced mainly by imbalances in loads across the grid and load operation variability [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Negative‐sequence voltage elimination for distributed generators in grid‐feeding operation mode

Rey

Castilla²,

Miret³

et al. 2020

IET Power Electronics

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A major concern of the power quality in distributed systems is related to the mitigation of voltage imbalances. This function can be implemented directly in the control system of the distributed generation power converters working simultaneously with the standard operation modes. This study presents a negative-sequence voltage elimination technique for distributed generators in grid-feeding operation mode. The proposal guarantees a complete elimination of the negativesequence voltage, while operating without a priori in-depth knowledge of the grid configuration and its characteristics. The proposed control architecture is presented together with its pseudocode, a controller flowchart and a discussion of the implementation aspects. A closed-loop modelling is derived based on a complex transfer function approach, which is used to determine stability margins and control design guidelines. A laboratory setup was implemented to verify the performance of the proposed strategy. Nomenclature Grid-connected DG unit scheme L LCL filter's inverter-side inductance C LCL filter's capacitor L 0 LCL filter's grid-side inductance Z L equivalent impedance of the distribution line Z local load i abc output current of the inverter v abc output voltage of the DG unit Notations for αβ, positive-and negative-sequence components x α component α of the variable x x β component β of the variable x x αβ compact notation of the components α and β of x x α + positive-sequence component of x α x β + positive-sequence component of x β x αβ + compact notation of the positive-sequence components of x α and x β x ref, α + positive-sequence reference of x α x ref, β + positive-sequence reference of x β x ref, αβ + compact notation of the positive-sequence references of x α and x β Parameters of the proposed control strategy K complex gain of the control strategy K r real component of K K i imaginary component of K

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A novel method for voltage support control under unbalanced grid faults and grid harmonic voltage disturbances

Cited by 20 publications

References 44 publications

Control Strategy for Distribution Generation Inverters to Maximize the Voltage Support in the Lowest Phase During Voltage Sags

Control Strategy for Distribution Generation Inverters to Maximize the Voltage Support in the Lowest Phase During Voltage Sags

EMD-Based Feature Extraction for Power Quality Disturbance Classification Using Moments

Negative‐sequence voltage elimination for distributed generators in grid‐feeding operation mode

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