scholarly journals Constant Voltage Model of DFIG-Based Variable Speed Wind Turbine for Load Flow Analysis

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8549
Author(s):  
Rudy Gianto
Keyword(s):  
Steady State ◽  
Power Systems ◽  
Power Factor ◽  
Power Plants ◽  
Flow Analysis ◽  
Load Flow ◽  
Constant Voltage ◽  
Load Flow Analysis ◽  
Proposed Model ◽  
Doubly Fed

At present, the penetration of wind-driven electric generators or wind power plants (WPPs) in electric power systems is getting more and more extensive. To evaluate the steady state performances of such power systems, developing a valid WPP model is therefore necessary. This paper proposes a new method in modeling the most popular type of WPP, i.e., DFIG (doubly fed induction generator)-based WPP, to be used in power system steady state load flow analysis. The proposed model is simple and derived based on the formulas that calculate turbine mechanical power and DFIG power. The main contribution of the paper is that, in contrast to the previous models where the DFIG power factor has been assumed to be constant at unity, the constant voltage model proposed in this paper allows the power factor to vary in order to keep the voltage at the desired value. Another important contribution is that the proposed model can be implemented in both sub-synchronous and super-synchronous conditions (it is to be noted that most of the previous models use two different mathematical models to represent the conditions). The case study is also presented in the present work, and the results of the study confirm the validity of the proposed DFIG model.

scholarly journals Fast and Accurate Load Flow Solution for On-line Applications Using ANN

2017 ◽  
Vol 1 (2) ◽  
Author(s):  
Wael Abdullah Alsulami
Keyword(s):  
Steady State ◽  
Power Systems ◽  
Flow Analysis ◽  
Load Flow ◽  
Line Load ◽  
Large Power ◽  
Flow Solution ◽  
Load Flow Analysis ◽  
On Line ◽  
Bus Voltage

This paper aims to develop a fast load flow computation technique without sacrificing accuracy for various on-line applications of large power systems. Both planning and operation of any power system requires the conduct of many load flow analyses corresponding to various operating modes with different system loading conditions and network configurations. Load flow analysis is performed for the determination of steady state operating status of power systems in terms of bus voltage magnitudes and angles, real and reactive powers and the transmission line losses. The load flow analysis involves the solution of non-linear algebraic equations and hence the conventional load flow algorithms are iterative in nature. The state-of-the-art approach for load flow analysis is based on Newton-Raphson algorithm (NRLF) or its derivatives such as fast decoupled load flow. As these methods are capable of providing the steady state solution within the specified accuracy, these techniques are effectively utilized as a planning tool by various utilities throughout the world. However, these are seen to be ineffective for on-line computations of practical large power systems because of the significant computational over-head due to the inherent iterative nature of such algorithms. Even though the non-iterative DC load flow approach, derived out of NRLF is computationally faster than the conventional techniques, solution accuracy is significantly less than that of its iterative counterparts. Hence, this paper proposes to develop a fast and accurate approach for the on-line load flow analysis. It is proposed to apply artificial neural network (ANN) technique as these are seen to be non-algorithmic in nature. The multi-layer feed-forward ANN for the load flow solution used in this study has one hidden layer with 100 neurons in addition to the input and output layers.  The real and reactive power demands are given as the inputs to the ANN. The output consists of the bus voltage magnitudes and angles at the load buses. The proposed ANN is trained using the conventional NRLF load flow solution of a practical power grid at various load levels. The investigations revel that the ANN as a potential tool for the on-line load flow solution of practical power systems.  

Operation Characteristics of Zone 3 Distance Protection in Wind Power Systems with Fixed-Speed Induction Generators

2011 ◽  
Vol 12 (4) ◽  
Author(s):  
Shenghu Li
Keyword(s):  
Power Systems ◽  
Wind Power ◽  
Reactive Power ◽  
Flow Analysis ◽  
Load Flow ◽  
Synchronous Generators ◽  
Induction Generators ◽  
Load Flow Analysis ◽  
Wind Power Systems ◽  
Operation Characteristics

The induction generators (IGs) are basic to wind energy conversion. They produce the active power and consume the reactive power, with the voltage characteristics fragile compared with that of the synchronous generators and doubly-fed IGs. In the stressed system states, they may intensify var imbalance, yielding undesirable operation of zone 3 impedance relays.In this paper, the operation characteristics of the zone 3 relays in the wind power systems is studied. With the theoretical and load flow analysis, it is proved that the equivalent impedance of the IGs lies in the 2nd quadrature, possibly seen as the backward faults by the mho relays, i.e. the apparent impedance enters into the protection region from the left side. The undesirable operation may be caused by more wind power, larger load, less var compensation, and larger torque angle.

scholarly journals Analisis Pemasangan Filter Pasif Untuk Mengurangi Harmonisa Pada Transformator Rectifier Di PT. Indah Kiat Pulp And Paper Perawang

SainETIn ◽  
2020 ◽  
Vol 3 (2) ◽  
pp. 59-68
Author(s):  
Rido Rahmadani
Keyword(s):  
Power Factor ◽  
Low Voltage ◽  
Flow Analysis ◽  
Harmonic Distortion ◽  
Chloride Ion ◽  
Load Flow ◽  
Electrolysis Process ◽  
Pulp Industry ◽  
Load Flow Analysis ◽  
Power Load

The chlor-alkali process is an electrolysis process which plays an important role in the chemical industry such as the pulp industry. The process produces a product in the form of H2 gas, CL2 gas and NaOH (where the source of chloride ion used is NaCl). This electrolysis process requires a dirrect current with a large current  and a low voltage. In this electrolysis process a three phase controlled 12 pulse rectifiers are used which a connected with multi-winding transformers. In the rectifiers process there will be harmonic distortion on the source side of the transformer which can reduce the power quality of the system. To overcome the harmonic problems that occur in the system, an installation analysis of the equipment in the form of a passive single tuned  filter is aimed at reducing harmonic distortion of current and voltage and increasing the power factor (cos φ). From the result of harmonic analysis using ETAP software, after the installation of harmonic filters orde 11, 13 and 23, the harmonic current value (THDI) and harmonic voltage (THDV) has decreased, namely, before the filter installation, THDI value is 6,5% whereas after installation of filters, THDI value becomes 0,98%, thus there is a THDI decrease of 5,52%. Furthermore, for the voltage harmonic value (THDV) before filter installation is 1,48% while after filtering, THDV value becomes 0,26%, thus there is a THDV decrease of 1,22%. From the results of the simulation of the flow of power (load flow analysis), after installation of filters there is an increase in the value of the power factor (cos φ). Namely, before the filter installation, the value of power factor (cos φ) is 0,8 while after the filter installation the value of the power factor (cos φ) to 0,96, thus an increase in the power factor (cos φ) of 16%.   Keywords : harmonic filter, single tuned filter, power factor, transformer rectifier

scholarly journals Comparison of Solvers Performance for Load Flow Analysis

2019 ◽  
Vol 3 (1) ◽  
pp. 26 ◽  
Author(s):  
Vishnu Sidaarth Suresh
Keyword(s):  
Steady State ◽  
Power System ◽  
Reactive Power ◽  
Flow Analysis ◽  
Steady State Solution ◽  
Load Flow ◽  
State Solution ◽  
Computational Time ◽  
Load Flow Analysis ◽  
Active And Reactive Power

Load flow studies are carried out in order to find a steady state solution of a power system network. It is done to continuously monitor the system and decide upon future expansion of the system. The parameters of the system monitored are voltage magnitude, voltage angle, active and reactive power. This paper presents techniques used in order to obtain such parameters for a standard IEEE – 30 bus and IEEE-57 bus network and makes a comparison into the differences with regard to computational time and effectiveness of each solver

scholarly journals Voltage Instability Analysis Using Mipower

2020 ◽  
pp. 220-225
Keyword(s):  
Power Factor ◽  
Power Flow ◽  
Flow Analysis ◽  
Minimum Cost ◽  
Load Flow ◽  
Instability Analysis ◽  
Voltage Instability ◽  
Load Flow Analysis ◽  
Newton Raphson ◽  
Raphson Method

Load Flow Analysis helps in error free operation of power system and also useful in forecasting the required equipment for expansion of the system. By forecasting the magnitude of the supply required along with effects caused by single or multiple defects in the system and calculating the magnitude of errors, it is very easy to compensate them using various techniques with minimum cost and effort. It means before installation the favorable sites and size of the infrastructure used are determined to maintain the power factor in the system. Here Power Flow Analysis is performed using Newton Raphson method. This method is used in solving power flow studies of various number of busesunder various conditions. In any network there will be undesired rise or drop or dissipation of voltage. Voltage instability decreases the efficiency of the system and also damages the equipment used. Hence voltage instability analysis is performed and magnitude of the instability is calculated and compensated using various techniques. Here we performed Load Flow Analysis on a 5bus system and Voltage Instability Analysis is also performed to the same with necessary outputs.[7]

An Educational Software Package for Power Systems Analysis and Operation

2005 ◽  
Vol 42 (4) ◽  
pp. 369-382 ◽  
Author(s):  
T. Yalcinoz
Keyword(s):  
Power Systems ◽  
Systems Analysis ◽  
Software Package ◽  
Transient Stability ◽  
Educational Software ◽  
Unit Commitment ◽  
Flow Analysis ◽  
Load Flow ◽  
Fault Analysis ◽  
Load Flow Analysis

This paper presents a software package developed in Matlab for teaching power systems analysis and operation. The software package is used to support and enhance power engineering education at both undergraduate and postgraduate levels. The application programs in this package include fault analysis, load flow analysis, transient stability, economic dispatch, unit commitment and load forecasting. All modules of the package are independent of each other. The students or researchers can make copies of the software to study and can modify any module of the package.

Optimal Power Distribution System Planning and Analysis Using Q-GIS and Soft Computing

2020 ◽  
Vol 12 (1) ◽  
pp. 70-83
Author(s):  
Shabbiruddin ◽  
Sandeep Chakravorty ◽  
Karma Sonam Sherpa ◽  
Amitava Ray
Keyword(s):  
Power Systems ◽  
Power Distribution ◽  
Distribution System ◽  
Flow Analysis ◽  
Integrated Approach ◽  
Load Flow ◽  
Strategic Decisions ◽  
Power Distribution System ◽  
Load Flow Analysis ◽  
Private And Public

The selection of power sub-station location and distribution line routing in power systems is one of the important strategic decisions for both private and public sectors. In general, contradictory factors such as availability, and cost, affects the appropriate selection which adheres to vague and inexact data. The work presented in this research deals with the development of models and techniques for planning and operation of power distribution system. The work comprises a wider framework from the siting of a sub-station to load flow analysis. Work done also shows the application of quantum- geographic information system (Q-GIS) in finding load point coordinates and existing sub-station locations. The proposed integrated approach provides realistic and reliable results, and facilitates decision makers to handle multiple contradictory decision perspectives. To accredit the proposed model, it is implemented for power distribution planning in Bihar which consists of 9 divisions. A Cubic Spline Function-based load flow analysis method is developed to validate the proposal.

scholarly journals Modelling and Validation of a Grid-Connected DFIG by Exploiting the Frequency-Domain Harmonic Analysis

2020 ◽  
Vol 10 (24) ◽  
pp. 9014
Author(s):  
Emmanuel Hernández-Mayoral ◽  
Reynaldo Iracheta-Cortez ◽  
Vincent Lecheppe ◽  
Oscar Alfredo Jaramillo Salgado
Keyword(s):  
Pulse Width Modulation ◽  
Flow Analysis ◽  
Power Converter ◽  
Load Flow ◽  
Operating Conditions ◽  
Electrical Grid ◽  
Wind Energy Conversion Systems ◽  
Load Flow Analysis ◽  
Energy Conversion Systems ◽  
Doubly Fed

Wind Energy Conversion Systems (WECS) based on a Doubly-Fed Induction Generator (DFIG) represent the most common configuration employed in wind turbines. These systems involve injecting harmonic currents toward an electrical grid from a back-to-back power converter, potentially creating voltage distortions. To assess this phenomenon, a case study of a 3 kW DFIG-based wind turbine connected to the electrical grid is presented for analysis in the harmonic domain. Initially, a DFIG-based load flow analysis for determining the operating conditions is tackled at the fundamental frequency. Then, the modelling of a DFIG under steady-state operating conditions at harmonic frequencies is analyzed discussing its characteristics in the harmonic domain. The high-frequency harmonics in the output voltage of a pulse width modulation-driven inverter feeding the rotor windings of a DFIG and its connection to a three-winding transformer are also analyzed. This investigation produced a complete model of the DFIG connected to the electrical grid. The results demonstrated that although a considerable harmonic contribution up to the 25th order exists, it remains harmless since it is below 5%, according to the Std. IEEE 519.

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