Simulation of three-phase transformer inrush currents by using backward and numerical differentiation formulae

Tokić, Amir; Milardić, Viktor; Uglešić, Ivo; Jukan, Admir

doi:10.1016/j.epsr.2015.05.020

Cited by 13 publications

(9 citation statements)

References 24 publications

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“…When modelling a transformer, it is necessary to consider transient analysis as it has two main aspects which are the nonlinearity and frequency dependency. Nonlinearity arises from the magnetic core saturation region, whereas frequency affects winding and core sections [24]. On the other hand, the steady state transformer model based on matrix representation can be descried as follows:…”

Section: Modelling Of Power Transformersmentioning

confidence: 99%

“…One of the main concerns in transient analysis is stiffness since the problem may swing from nonstiff to extremely stiff situation which may affect the algorithm used and the number of steps [23]. Since some numerical methods require small step size to ensure stability, the explicate numerical method needs to avoid the stiff system [24]. Further development of the model can be achieved by taking into account winding and core topology, frequency dependency, and capacitor effect.…”

Section: Modelling Of Power Transformersmentioning

confidence: 99%

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Identification of Power Transformer Currents by Using Random Forest and Boosting Techniques

Khatib

Arar

2020

Mathematical Problems in Engineering

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In this research, a differential protection technique for a power transformer is proposed by using random forest and boosting learning machines. The proposed learning machines aim to provide a protection expert system that distinguishes between different transformer status which are normal, inrush, overexcitation, CT saturation, or internal fault. Data for 20 different transformers with 5 operating cases are used in this research. The utilized random forest and boosting techniques are trained using these data. Meanwhile, the proposed models are validated by other measures such as out-of-bag error and confusion matrix. In addition, variable importance analysis that shows signal’s component importance inside a transformer at different instances is provided. According to the result, the proposed random forest model successfully identifies all of the current cases (100% accuracy for the conducted experiment). Meanwhile, it is found that it is less accurate as a conditional monitoring element with accuracy in the range of 97%–98%. On the other hand, the proposed boosting model identifies all of the currents for both cases (100% accuracy for the conducted experiment). In addition to that, a comparison is conducted between the proposed models and other AI-based models. Based on this comparison, the proposed boosting model is the simplest and the most accurate model as compared to other models.

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Section: Modelling Of Power Transformersmentioning

confidence: 99%

Section: Modelling Of Power Transformersmentioning

confidence: 99%

Identification of Power Transformer Currents by Using Random Forest and Boosting Techniques

Khatib

Arar

2020

Mathematical Problems in Engineering

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“…There is set of standards that consider voltage quality area, issued by IEEE (Institute of Electrical and Electronics Engineers). List of those standards can partly be found in [25]. Some voltage quality limits (available to authors) in scope for this analysis are presented in Table 6.InTable 6, compliance limits for statistical evaluation of 95% of time are shown.…”

Section: Ieee Standardsmentioning

confidence: 99%

PV Plant Influence on Distribution Grid in Terms of Power Quality Considering Hosting Capacity of the Grid

Ramljak¹,

Bago²

2019

Electric Power Conversion

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Photovoltaic plants penetrate rapidly in distribution grid. Problems with their integration in distribution grid can exist in terms of load flow, protection settings, power quality, etc. This chapter analyzes influence of photovoltaic plants connection in distribution grid (0.4 and 10 kV voltage level) on power quality. The main focus will be on influence of photovoltaic plant connection point on distribution grid (hosting capacity-strength of the grid) in terms of power quality. Norms and regulations about influence of photovoltaic plants on distribution grid in terms of power quality will be analyzed. Influence of photovoltaic plants on distribution grid in theoretical aspects will be presented. Several case studies then will be described. Those case studies present different connection points of photovoltaic plants on distribution grid. Comparison of theoretical assumptions and real case studies will be compared. Some observations of real case studies and their impact on theoretical aspects, norms, and regulations about photovoltaic plant influence on distribution grid will be introduced.

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“…Significant research studies have been carried out to explain inrush current phenomenon by deriving the mathematical formulations. The application of some of the presented techniques for formulating complicated differential equations have been investigated in (Tokic et al , 2015; Cardelli et al , 2015; Cardelli and Faba, 2014; Faiz et al , 2008; Adly et al , 2003). Two main tendencies for solving inrush current problem are the analytical methods and the numerical approaches (Diaz and Mombello, 2015).…”

Section: Introductionmentioning

confidence: 99%

A novel and accurate analytical-numerical method for inrush current modeling of three-limb power transformers

Taghikhani

2020

COMPEL

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Purpose Using appropriate solution techniques for transformer inrush current transient study is of great prominence owing to the inevitable inclusion of differential equations leading to complicated analysis procedures. This study aims to propose an analytical-numerical method to accurately analyze the three-phase three-limb core-type transformer inrush current in different cases considering the nonlinear behavior of the iron core. Design/methodology/approach The proposed method focuses on acquiring equations for inrush current and also the magnetic core flux by the application of a simulation-based iterative approach. In this regard, multiple integral equations are solved taking the time intervals into account. Then several derivations and integrations of matrix terms are substituted into the obtained results so as to simplify the solution process. Findings The method provides notable enhancements in computation time and also excellent qualities of accuracy compared with conventional numerical methods. Practical implications The proposed method is simulated for two three-phase transformers via MATLAB software. The obtained simulation results have been also compared with experimental tests. Originality/value Actually, the analytical-numerical method is capable of computing higher number of iterations in a shorter time efficiently, while making use of the conventional numerical procedures may not result in expected convergences. The simulation results of the proposed analytical-numerical technique illustrate a close agreement with the experimental test, and hence, verify the method preciousness.

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Simulation of three-phase transformer inrush currents by using backward and numerical differentiation formulae

Cited by 13 publications

References 24 publications

Identification of Power Transformer Currents by Using Random Forest and Boosting Techniques

Identification of Power Transformer Currents by Using Random Forest and Boosting Techniques

PV Plant Influence on Distribution Grid in Terms of Power Quality Considering Hosting Capacity of the Grid

A novel and accurate analytical-numerical method for inrush current modeling of three-limb power transformers

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