Models for wind turbine generating systems and their application in load flow studies

Divya, K.C.; Rao, P. Krishna

doi:10.1016/j.epsr.2005.10.012

Cited by 163 publications

(97 citation statements)

References 33 publications

(89 reference statements)

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“….5 (6) In addition, it is assumed that the TR is equipped with an on-load tap changer control system which is typically required to hold the voltage amplitude at bus S 1 at a specific level. This can be achieved if a suitable number of taps is available [31].…”

Section: Substation Transformermentioning

confidence: 99%

“…This kind of stochastic reactive power from wind generators was also studied in [5] for a medium-voltage (MV) network. The works in [4,5] used a model for reactive power production from wind turbines based on a detailed induction machine equivalent circuit as presented in [6]. Other researchers [7], however, used a different model based on an electrical model of a wind turbine with a full scale converter.…”

Section: Introductionmentioning

confidence: 99%

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On Variable Reverse Power Flow-Part I: Active-Reactive Optimal Power Flow with Reactive Power of Wind Stations

Gabash

2016

Energies

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It has recently been shown that using battery storage systems (BSSs) to provide reactive power provision in a medium-voltage (MV) active distribution network (ADN) with embedded wind stations (WSs) can lead to a huge amount of reverse power to an upstream transmission network (TN). However, unity power factors (PFs) of WSs were assumed in those studies to analyze the potential of BSSs. Therefore, in this paper (Part-I), we aim to further explore the pure reactive power potential of WSs (i.e.

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Section: Substation Transformermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

On Variable Reverse Power Flow-Part I: Active-Reactive Optimal Power Flow with Reactive Power of Wind Stations

Gabash

2016

Energies

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“…The Developed model has active and reactive power expressions in terms of induction machine impedance parameters, input power and terminal voltages. In the Developed model, magnitude of the positive-sequence rotor side voltage is expressed via bi-quadratic equation, which is generally used to calculate node voltages in the load flow analysis [10,11,14,18,19]. In the study of Feijôo and Villanueva [18], a slightly modified model of the Eminoglu et al study [10] is given and the advantages of the bi-quadratic equation based models are highlighted.…”

Section: Introductionmentioning

confidence: 99%

“…In Equations (18) and (19), θ m denotes phase angle difference between voltage and current of phase m. If phase active and reactive powers have a minus (−) sign, it can be mentioned that these powers are injected from generator to grid; otherwise, these powers flow from grid to the generator. Note that, in the next sections, due to the fact that the injected active and demanded reactive power are given in the analysis, both of them will have a positive sign.…”

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confidence: 99%

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A New Wind Turbine Generating System Model for Balanced and Unbalanced Distribution Systems Load Flow Analysis

et al. 2018

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Abstract:Wind turbine generating systems (WTGSs), which are conventionally connected to high voltage transmission networks, have frequently been employed as distributed generation units in today's distribution networks. In practice, the distribution networks always have unbalanced bus voltages and line currents due to uneven distribution of single or double phase loads over three phases and asymmetry of the lines, etc. Accordingly, in this study, for the load flow analysis of the distribution networks, Conventional Fixed speed Induction Generator (CFIG) based WTGS, one of the most widely used WTGS types, is modelled under unbalanced voltage conditions. The Developed model has active and reactive power expressions in terms of induction machine impedance parameters, terminal voltages and input power. The validity of the Developed model is confirmed with the experimental results obtained in a test system. The results of the slip calculation based phase-domain model (SCP Model), which was previously proposed in the literature for CFIG based WTGSs under unbalanced voltages, are also given for the comparison. Finally, the Developed model and the SCP model are implemented in the load flow analysis of the IEEE 34 bus test system with the CFIG based WTGSs and unbalanced loads. Thus, it is clearly pointed out that the results of the load flow analysis implemented with both models are very close to each other, and the Developed model is computationally more efficient than the SCP model.

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Unbalanced distribution power-flow model and analysis of wind turbine generating systems

Abdel‐Akher

Mahmoud

2012

Int. Trans. Electr. Energ. Syst.

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The paper presents an unbalanced three-phase power-flow model for wind turbine generating systems (WTGSs). The model takes into account voltage unbalance factor which exists at the point of common coupling. The developed model is integrated with the unbalanced forward/backward sweep power-flow method. The model comprises of three main components: they are the wind turbine, induction generator, and interface transformer to the grid. Due to their design symmetry, the generator and the transformer are modeled using symmetrical sequence networks. The results show that the developed model has robust convergence characteristics. The solution of the IEEE unbalanced radial feeders shows that the injected powers per phase due to the WTGS are not equal and strongly dependent on the voltage unbalance factor. The results also show that the simplified models based on positive sequence network lead to inaccurate overall power-flow solution.[9]. Ref.[10] developed a complete three-phase power-flow analysis; however, the injected active power due to WTGSs has been assumed equally divided among the three phases. This assumption may lead to incorrect results due to ignoring the internal equivalent circuit of generator and the voltage unbalance factor at the PCC.The majority of installed WTGSs utilize fixed-speed induction generators [9], [11]. The fixed speed WTGSs are preferred and widely commercialized due to its rigged construction and low cost [1]. In the previous work, induction generator has been modeled only by its positive sequence network. This model is accepted only under assumption of balanced operation [4-9]. The unbalanced system operation and the assumption of balanced WTGSs operation may lead to inadequate power-flow solution [10], [12,13]. Implicit representation of induction generator of positive-and negative-sequence networks is introduced in [14]. The resultant equivalent three-phase admittance matrix in phase components of the induction generator is integrated to Newton-Raphson power-flow solution. However, this model is machine-slip dependent, i.e. the model cannot be solved without the assumption of prior knowledge of the machine slip [14].In WTGSs, if a generator is connected to the grid through a power conditioning unit, the WTGSs are simply modeled as a constant negative constant complex power load (PQ). However, if the generator terminals are directly connected to the grid, the internal circuit of the generator should be fully exploited in the power-flow analysis [15,16]. Three-phase machines used in generating systems are usually designed with maximum symmetry [15]. The stator of these machines comprises of three identical sets of coils. If these coils are excited, they produce balanced three-phase voltages, i.e. positive sequence voltages. Three-phase machines are considered as symmetrical elements [14][15][16][17]. However, due to the unbalance nature of distributions systems, negative and zero sequence currents are injected into the generator circuit causing unbalanced operation of the machine. In ord...

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Models for wind turbine generating systems and their application in load flow studies

Cited by 163 publications

References 33 publications

On Variable Reverse Power Flow-Part I: Active-Reactive Optimal Power Flow with Reactive Power of Wind Stations

On Variable Reverse Power Flow-Part I: Active-Reactive Optimal Power Flow with Reactive Power of Wind Stations

A New Wind Turbine Generating System Model for Balanced and Unbalanced Distribution Systems Load Flow Analysis

Unbalanced distribution power-flow model and analysis of wind turbine generating systems

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