scholarly journals Power Quality Improvement of a Solar Energy Conversion System by a Coordinated Active and LCL Filtering

Author(s):  
Atallah Ouai ◽  
Lakhdar Mokrani ◽  
Mohamed Machmoum ◽  
Azeddine Houari

Power converters play an essential role in Photovoltaic (PV) system to maximize the power transfer to the electrical grid. However, the generated harmonics in the grids due to these power converters and nonlinear loads are considered one of the encountered problems to overcome. This paper presents a decoupled control of PV field real power and reactive power injected to the high voltage network via a PWM inverter by using fuzzy logic controllers. Elsewhere, a procedure based on a coordinated active and LCL filtering is proposed to mitigate the harmonic current introduced by a nonlinear load and the inverter itself in such a way to enhance the power quality injected into the grid. The results obtained in the present study show the good performance of the suggested hybrid filtering approach and demonstrate that almost all harmonics orders of the grid current are well mitigated; the current Total Harmonic Distortion (THD) meets its standard and consequently the power quality is considerably enhanced.

In this paper, a PWM inverter is proposed for improvement of power quality i.e., reduction of total harmonic distortion (THD). The power quality problems reduce the lifetime and performance of equipments. The proposed system reduces the THD which is generated from the nonlinear loads. Because presence of harmonics leads to problems like overheating, failure of insulation etc. Here the simulation results of the proposed system is studied using MATLAB SIMULINK. Using the system, a lower THD is achieved which shows the effectiveness of the system.


2021 ◽  
Vol 17 (2) ◽  
pp. 140-150
Author(s):  
Ahmed Qasim ◽  
Fadhil Tahir ◽  
Ahmed Alsammak

In light of the widespread usage of power electronics devices, power quality (PQ) has become an increasingly essential factor. Due to nonlinear characteristics, the power electronic devices produce harmonics and consume lag current from the utility. The UPQC is a device that compensates for harmonics and reactive power while also reducing problems related to voltage and current. In this work, a three-phase, three-wire UPQC is suggested to reduce voltage-sag, voltage-swell, voltage and current harmonics. The UPQC is composed of shunt and series Active Power Filters (APFs) that are controlled utilizing the Unit Vector Template Generation (UVTG) technique. Under nonlinear loads, the suggested UPQC system can be improved PQ at the point of common coupling (PCC) in power distribution networks. The simulation results show that UPQC reduces the effect of supply voltage changes and harmonic currents on the power line under nonlinear loads, where the Total Harmonic Distortion (THD) of load voltages and source currents obtained are less than 5%, according to the IEEE-519 standard.


2021 ◽  
Vol 13 (2) ◽  
pp. 505
Author(s):  
Sumaya Jahan ◽  
Shuvra Prokash Biswas ◽  
Md. Kamal Hosain ◽  
Md. Rabiul Islam ◽  
Safa Haq ◽  
...  

The use of different control techniques has become very popular for controlling the performance of grid-connected photovoltaic (PV) systems. Although the proportional-integral (PI) control technique is very popular, there are some difficulties such as less stability, slow dynamic response, low reference tracking capability, and lower output power quality in solar PV applications. In this paper, a robust, fast, and dynamic proportional-integral resonance controller with a harmonic and lead compensator (PIR + HC + LC) is proposed to control the current of a 15-level neutral-point-clamped (NPC) multilevel inverter. The proposed controlled is basically a proportional-integral resonance (PIR) controller with the feedback of a harmonic compensator and a lead compensator. The performance of the proposed controller is analyzed in a MATLAB/Simulink environment. The simulation result represents admirable performance in terms of stability, sudden load change response, fault handling capability, reference tracking capability, and total harmonic distortion (THD) than those of the existing controllers. The responses of the inverter and grid outlets under different conditions are also analyzed. The harmonic compensator decreases the lower order harmonics of grid voltage and current, and the lead compensator provides the phase lead. It is expected that the proposed controller is a dynamic aspirant in the grid-connected PV system.


2015 ◽  
Vol 16 (4) ◽  
pp. 357-384 ◽  
Author(s):  
Suresh Mikkili ◽  
Anup Kumar Panda

Abstract Electrical power quality has been an important and growing problem because of the proliferation of nonlinear loads such as power electronic converters in typical power distribution systems in recent years. Particularly, voltage harmonics and power distribution equipment problems result from current harmonics produced by nonlinear loads. The Electronic equipment like, computers, battery chargers, electronic ballasts, variable frequency drives, and switch mode power supplies, generate perilous harmonics and cause enormous economic loss every year. Problems caused by power quality have great adverse economic impact on the utilities and customers. Due to that both power suppliers and power consumers are concerned about the power quality problems and compensation techniques. Power quality has become more and more serious with each passing day. As a result active power filter gains much more attention due to excellent harmonic and reactive power compensation in two-wire (single phase), three-wire (three-phase without neutral), and four-wire (three-phase with neutral) ac power networks with nonlinear loads. However, this is still a technology under development, and many new contributions and new control topologies have been reported in the last few years. It is aimed at providing a broad perspective on the status of APF technology to the researchers and application engineers dealing with power quality issues.


2021 ◽  
Vol 23 (12) ◽  
pp. 102-145
Author(s):  
V.A Deshmukh ◽  
◽  
B. Sridhar ◽  

In the next few years, more than 80% of AC power is to be processed through power converters owing to their benefits of energy conservation, flexibility, network interconnection, and weight and volume reduction in a number of equipment such as lighting arrestors, HVAC computers, fans, and so on.This paper gives an introduction on power quality (PQ), causes and effects of power quality problems. It also deals with power quality definitions, terminologies, standards, bench-marks, monitoring requirements, financial loss, and analytical quantification. It also discusses various types of nonlinear loads, which cause these power quality problems, they are illustrated, classified, modeled, quantified, and analyzed forassociated power quality issues.


Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 2021 ◽  
Author(s):  
Yuehui Chen ◽  
Zhao Huang ◽  
Zhenfeng Duan ◽  
Pengwu Fu ◽  
Guandong Zhou ◽  
...  

This paper solves the problem of reactive power and harmonics compensation in a high-voltage (HV) distribution network supplying nonlinear loads. An inductive filtering (IF) approach where passive filters connect to the filtering winding of a four-winding inductive filtering transformer (FW-IFT) is presented to enhance the power quality of the public grid. This method can not only greatly suppress harmonic currents of the medium and/or low-voltage (LV) side, but also prevent them from flowing into the public grid. The new main circuit topology, where the FW-IFT has specific filtering winding by adopting the ampere-turn balance of the transformer, is presented. On the basis of the structure of the FW-IFT, the magnetic potential balanced equation and inductive filtering technology, its equivalent circuit and mathematical model are established, and the filtering performances are analyzed in detail. Simulation and experimental results rated at SN-10/0.38 of the FW-IFT are presented to prove the efficacy of the comprehensive enhancement of power quality on the grid side.


Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 790 ◽  
Author(s):  
Matej Žnidarec ◽  
Zvonimir Klaić ◽  
Damir Šljivac ◽  
Boris Dumnić

Expanding the number of photovoltaic (PV) systems integrated into a grid raises many concerns regarding protection, system safety, and power quality. In order to monitor the effects of the current harmonics generated by PV systems, this paper presents long-term current harmonic distortion prediction models. The proposed models use a multilayer perceptron neural network, a type of artificial neural network (ANN), with input parameters that are easy to measure in order to predict current harmonics. The models were trained with one-year worth of measurements of power quality at the point of common coupling of the PV system with the distribution network and the meteorological parameters measured at the test site. A total of six different models were developed, tested, and validated regarding a number of hidden layers and input parameters. The results show that the model with three input parameters and two hidden layers generates the best prediction performance.


2014 ◽  
Vol 543-547 ◽  
pp. 878-883
Author(s):  
Jun Dong ◽  
Jian Guo Xu ◽  
Hao Zhang ◽  
Yu Jie Pei ◽  
Xian Feng Li

The cause serious deterioration in power quality problems for the growing impact and nonlinear load capacity, introduced SVC device in the role of modern power systems and applications. According to the lack of adequate regional dynamic reactive power regulation means to cause voltage fluctuations, harmonics exceeded the actual situation, through analysis and simulation of the existing 66kV grid power quality conditions, refers to the necessity of application of SVC, the compensation capacity for SVC, filter capacitor system parameters and control strategies were designed, the results show improved 220kV SVC reactive power flow distribution system, reducing the system once or twice a net loss, reducing the impact and harmonic interference voltage caused by nonlinear loads, system security, economic operation of great significance.


2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Z. Chelli ◽  
R. Toufouti ◽  
A. Omeiri ◽  
S. Saad

This paper focuses on a four-wire shunt active power filter (APF) control scheme proposed to improve the performance of the APF. This filter is used to compensate harmonic distortion in three-phase four-wire systems. Several harmonic suppression techniques have been widely proposed and applied to minimize harmonic effects. The proposed control scheme can compensate harmonics and reactive power of the nonlinear loads simultaneously. This approach is compared to the conventional shunt APF reference compensation strategy. The developed algorithm is validated by simulation tests using MATLAB Simulink. The obtained results have demonstrated the effectiveness of the proposed scheme and confirmed the theoretical developments for balanced and unbalanced nonlinear loads.


Author(s):  
V S Prasadarao K ◽  
K V Krishna Rao ◽  
P Bala Koteswara Rao ◽  
T. Abishai

Renewable energy sources (RES) are gaining more importance in the present scenario due to the depletion of fossil fuels and increasing power demand. Solar energy is the one of the most promising as it is clean and easily available source. The voltage obtained from the PV system is low. This voltage is increased by high step up dc-dc converter which uses only one switch leads to low switching losses and hence the efficiency of this converter is high. To get the good response this converter is operated in closed loop manner. Integration of PV system with existing grid has so many issues like distorted voltage, current and reactive power control etc. This paper presents a four leg inverter which works on hysteresis current control technique to address the power quality issues like reactive power compensation, balanced load currents and compensation of neutral current. The switching to the inverter is designed in such a way that it supplies the extra current to stabilise the current of the grid that is being supplied to the loads. Finally, the proposed technique is validated by using mat lab/Simulink software and corresponding results are presented in this paper.


Sign in / Sign up

Export Citation Format

Share Document