scholarly journals Performance analysis of facts devices for reduction of power quality issues in DFIG based WECS integrated to grid

2018 ◽  
Vol 7 (3.29) ◽  
pp. 49
Author(s):  
M Rama Sekhar Reddy ◽  
Dr M. Vijaya Kumar

Integration of a wind farm with electric grid is an issue that has gained interest due to poor power quality and unmatched power and frequency of grid. Maintenance of power quality has become an important factor in modern power systems. The usage of non-linear loads results in various power quality events which over a period would reduce life and deteriorate the performance of end user equipment. FACTS devices are available that use power electronic components provide efficient solutions for improving power quality in Distribution systems. This paper discusses performance of three FACTS devices SSSC, DSTATCOM and UPQC for mitigating voltage sags, swells and harmonics injected into a DFIG based WECS. The model is developed on MATLAB/ SIMULINK platform and results are presented.  

Author(s):  
Ayesha Haroon ◽  
Irfan Shafqat Javed ◽  
Huma Rehmat Baig ◽  
Ali Nasir

Over the past two decades, developing distributed energy sources in electric power grid have created new challenges related to the power quality, voltage adjustment and proficient energy utilization. Power electronic converters are widely used to interface the emerging energy systems (without and with energy storage) and smart buildings with the transmission and distribution systems. Flexible Ac Transmission Systems (FACTS) and Voltage-Source Converters (VSC), with smart dynamic controllers, are emerging as stabilization and power filtering equipment to improve the power quality. FACTS devices are of vital significance for tackling the problem of voltage instability which is inevitable and leads to losses in transmission system networks. These devices provide fast voltage regulation, ensure system stability and reactive power compensation. In this regard, modeling, control and appropriate placement of these devices in the transmission lines have been of great importance for researchers of power transmission systems. By using high speed power electronic converters, FACTS perform many times faster than the conventional compensation techniques. FACTS not only provide fast voltage regulation but also damping of active power oscillations and reactive power compensation. Hence, they increase the availability and reliability of the power systems. But, the functioning of a FACTS device extremely reckons upon its parametric quantity, appropriate placement, and sizing in the power network. In this paper, an extensive literature survey is presented to discuss and investigate these parameters of FACTS devices.


Author(s):  
Okan Ozgonenel ◽  
◽  
Kubra Nur Akpinar ◽  

Electrical power systems are expected to transmit continuously nominal rated sinusoidal voltage and current to consumers. However, the widespread use of power electronics has brought power quality problems. This study performs classification of power quality disturbances using an artificial neural network (ANN). The most appropriate ANN structure was determined using the Box-Behnken experimental design method. Nine types of disturbance (no fault, voltage sag, voltage, swell, flicker, harmonics, transient, DC component, electromagnetic interference, instant interruption) were investigated in computer simulations. The feature vectors used in the identification of the different types of disturbances were produced using the discrete wavelet transform and principal component analysis. Our results show that the optimized feed forward multilayer ANN structure successfully distinguishes power quality disturbances in simulation data and was also able to identify these disturbances in real time data from substations.


Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3292 ◽  
Author(s):  
Andres Tarraso ◽  
Ngoc-Bao Lai ◽  
Gregory N. Baltas ◽  
Pedro Rodriguez

The variable and unpredictable behavior of renewable energies impacts the performance of power systems negatively, threatening their stability and hindering their efficient operation. Flexible ac transmission systems (FACTS) devices are able to emulate the connection of parallel and series impedances in the transmission system, which improves the regulation of power systems with a high share of renewables, avoiding congestions, enhancing their response in front of contingencies and, in summary, increasing their utilization and reliability. Proper control of voltage and current under distorted and unbalanced transient grid conditions is one of the most critical issues in the control of FACTS devices to emulate such apparent impedances. This paper describes how the synchronous power controller (SPC) can be used to implement virtually synchronous FACTS. It presents the SPC functionalities, emphasizing in particular the importance of virtual admittance emulation by FACTS devices in order to control transient unbalanced currents during faults and attenuate harmonics. Finally, the results demonstrate the effectiveness of SPC-based FACTS devices in improving power quality of electrical networks. This is a result of their contribution to voltage balancing at point of connection during asymmetrical faults and the improvement of grid voltage quality by controlling harmonics flow.


2014 ◽  
Vol 875-877 ◽  
pp. 1923-1928 ◽  
Author(s):  
Surya Hardi ◽  
Ismail Daut ◽  
Ismail Rohana ◽  
Muhd Hafizi

Voltage sags and interruption are one of most important of power quality problems. They can influence performance of equipment such as induction motors. They are generally caused by short circuit faults in transmission and distribution systems which propagate in entire of power systems. When their appear at a motor terminal, its effects are the speed and the torque will decrease to a level lower than values of the normal and even the motor become stall if magnitude of the voltage sags and duration exceed certain limit. The voltage can return to nominal voltage after end of the voltage sag and interruption. The motor will experience re-acceleration to normal condition is accompanied by large inrush current. A study on induction motors was carried out to confirm these effects. Single-phase and three-phase of small induction motors were used for investigating the effects caused by symmetrical voltage sags and interruption through experimental and simulation.


2019 ◽  
Vol 8 (3) ◽  
pp. 7366-7369

Power quality has been an issue in electrical power systems. Disturbances occur in power quality which effects machines, some electric devices and severe cause will get very serious damages. For normal and efficient operation it’s necessary to compensate and acknowledge every type of the disturbances at earlier time of the power system. Many sorts of Custom Power Devices (CPD’s) are used to resolve these issues .Here at present, one in every of those devices, Dynamic Voltage restorer (DVR) is conferred. In power distribution systems this is often best and effective device employed. During this project new structure and control methodology of multifunctional DVRs for voltage quality correction are mentioned. Proportional Integral Controller and Fuzzy Logic Controller are used for the PQ improvement. The performance of the device and Total Harmonic Distortion is compared with each other. The performance of the device like voltage swell, sag is projected.


Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6286
Author(s):  
Daniela Pagnani ◽  
Frede Blaabjerg ◽  
Claus Leth Bak ◽  
Filipe Miguel Faria da Silva ◽  
Łukasz H. Kocewiak ◽  
...  

A review of the ongoing research on black start (BS) service integrated with offshore wind farms (OWFs) is presented in this paper. The overall goal is to firstly gain a better understanding of the BS capabilities required by modern power systems. Subsequently, the challenges faced by OWFs as novel BS service providers as well as an outlook on the ongoing research which may provide solutions to these are presented. OWFs have the potential to be a fast and environmentally friendly technology to provide BS services for power system restoration and, therefore, to ensure resiliency after blackouts. As a power electronic-based system, OWFs can be equipped with a self-starter in the system in order to perform BS. The self-start unit could be a synchronous generator (SG) or a power electronic unit such as a grid-forming (GFM) converter. Preliminary BS studies performed in PSCAD/EMTDC are presented in a simplified OWF system via an SG as the self-start unit. Consequently, technical challenges during the BS procedure in an OWF benchmark system are outlined via theoretical discussions and simulations results. This is useful to understand the threats to power electronics during BS. Finally, the most relevant GFM strategies in the state-of-the-art literature are presented and their application to OWF BS is discussed.


DYNA ◽  
2015 ◽  
Vol 82 (192) ◽  
pp. 26-36
Author(s):  
Herbert Enrique Rojas-Cubides ◽  
Audrey Soley Cruz-Bernal ◽  
Harvey David Rojas-Cubides

<p class="Abstract"><span lang="EN-US">Voltage sags are the most common power quality disturbances in electrical facilities. It may cause malfunction in sensitive equipment and process interruption. The distribution static compensator (DSTATCOM) is a device that can compensate voltage sags by injecting reactive power into distribution system. This paper shows the influence on voltage sags characteristics by the presence of twelve-pulse DSTATCOM in the modified IEEE-13 distribution system. The analysis is performed by means of a random generation of disturbances using a MATLAB routine to identify the critical buses of the test system. Further, the DSTATCOM model taking advantage of the available elements from ATP/EMTP software is described. Simulations show that when DSTATCOM is placed directly to affected bus it is possible to obtain a complete mitigation of the voltage sag. Finally, the relation between the reactive power injected by DSTATCOM, the type of voltage sag and the location of affected bus is considered.</span></p>


2014 ◽  
Vol 945-949 ◽  
pp. 3060-3068 ◽  
Author(s):  
Anderson Roges Teixeira Góes ◽  
Maria Teresinha Arns Steiner ◽  
Pedro José Steiner Neto ◽  
Osíris Canciglieri

In this paper, we propose a methodology to classify Power Quality (PQ) in distribution systems based on voltage sags. The methodology uses the KDD process (Knowledge Discovery in Databases) in order to establish a quality level to be printed in labels. The methodology was applied to feeders on a substation located in Curitiba, Parana, Brazil, considering attributes such as sag length (remnant voltage), duration and frequency (number of occurrences on a given period of time). On the Data Mining stage (the main stage on KDD Process), three different techniques were used, in a comparative way, for pattern recognition, in order to achieve the quality classification for the feeders: Artificial Neural Networks (ANN); Support Vector Machines (SVM) and Genetic Algorithms (GA). By printing a label with quality level information, utilities companies (power concessionaires) can get better organized for management and mitigation procedures by establishing clear targets. Moreover, the same way costumers already receive information regarding PQ based on interruptions, they will also be able to receive information based on voltage sags.


Author(s):  
Abirami Periaswamy ◽  
Merin Lizbeth George

<p>Now a days there is a widespread use of  semiconductor devices, which are mostly implemented as the power switches for converters and inverters. These converters and inverters play a vital role in power systems both in transmission and distribution systems. This provides a way for the introduction of harmonics in the power system which leads to poor power quality. To overcome this many solutions have been suggested by the research community but each solution holds its own merits and demerits. Of all these suggested solutions, the Dynamic Voltage Restorer is one of the most cost effective systems for various power quality issues. In this paper the DVR is considered for enhancing the power quality by reducing the harmonics generated because of sensitive loads. Here the power quality is enhanced by controlling the DVR using Neural Network Controller which is trained by Levenberg Marquardt algorithm. In this paper the THD analysis of the voltage quantity is analysed by introducing an unbalanced three phase fault in the system. The simulation is done by using MATLAB/Simulink. From the results, it is verified that the harmonics are reduced by the NN controlled DVR unit. Also the simulation results are verified with the hardware results. </p>


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