Power Quality Improvement Research Papers (original) (raw)

—This paper proposes a new five-level hybrid topology combining features of neutral point clamped and flying capacitor inverters. The proposed topology provides a tradeoff between different component counts to achieve a good loss distribution, avoid direct series connection of semiconductor devices, keep the balanced operation of dc-link capacitors while keeping the number of costly components such as capacitors and switches low. The required modulation strategy is developed and the operation of the proposed topology is studied. The features of the proposed topology are investigated and compared to other available topologies. Simulation results are provided to verify the performance of the converter for medium voltage applications.

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- Power Quality Improvement

Power electronics play a significant role in different areas of technology, more usage of power electronic devices lead to more harmonic content and various power quality issues in the system. Therefore, power quality gains more significance in the current era of research. Power electronics equipment's with non-linear loads concludes with more harmonic disturbances and lower power factor. Harmonic impurities are the major problem ingredient due to the connection of non-linear load. To lessen the harmonics usually passive filters are used. The major objective of this work is to monitor and analyse the power quality of uninterrupted power supply by means of DAQ system that gathers real time data on the system and then the data is analysed using National Instruments LabVIEW. Once power quality analysis is done, a new technique of filter implementation using output transformer of the UPS was explored and passive filter was simulated using MATLAB/Simulink and then simulated filter was implemented in order to achieve power quality improvement.

In this paper, power quality improvement by using a new structure of non superconducting fault current limiter (NSFCL) is discussed. This structure prevents voltage sags on Point of Common Coupling (PCC) just after fault occurrence, because of its fast operation. On the other hand, previously used structures produce harmonics on load voltage and have ac losses in normal operation. New structure has solved this problem by using dc voltage source. The proposed structure is simulated using PSCAD/EMTDC software and ...

- by Mohsen Jafari
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- Power Quality, Semiconductor Devices, Pscad, Fault Current Limiters
- by utsav gonawala
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- Power Quality Improvement

Besides quantity, the quality of power is also equally important. Poor power quality decreases the efficiency and misoperation of electrical and electronic devices, this may result interrupted electrical power supply. Due to recent development of electronics and computer based automated and smart devices in every field e.g. medical, bank, industry, quality of power becomes more and more important as these devices require best power quality. Power quality mitigation becomes very important as we cannot avoid the nonlinear loadings and many more issues which is responsible for poor power quality. In this paper various power quality mitigation techniques are discussed such as Distribution Static Synchronous Compensator (DSTATCOM), Static VAR Compensator (SVC), Dynamic Voltage Restorer (DVR) and Unified Power Quality Compensator (UPQC) for the improvement of power quality in manufacturing industries. Recent developments in mitigation techniques are also discussed. Different techniques are explained in chronological order. Impacts of different techniques for different disturbances are also mentioned. Index Terms: Dynamic Voltage Restorer (DVR), Unified Power Quality Conditioner (UPQC), Distribution Static Compensator (DSTATCOM), Transient Voltage Surge Suppressors (TVSS), Voltage Regulators, Uninterruptible Power Supply (UPS) Solid State Breaker, Static Current Limiter.

- by Sunil Singh
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- Power Quality, Power Quality Improvement

This paper reviews the performance of detailed and average model for distribution static compensator (DSTATCOM) in order to remove voltage flicker, regulate the voltage at point of common coupling (PCC), power factor correction and harmonics elimination. In these models, d-q theory is used to extract fundamental active and reactive power components of the load currents which will be required to estimate the reference source currents. Both models are evaluated and
compared in MATLAB/Simulink based simulation platform.

- by Muhd Hafizi Idris and +3
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- Power Quality, Matlab/Simulink, Dstatcom, Matlab & Simulink programming

Distributed generation (DG) with converter interface
to the grid is found in many of the green power resources
applications. In this paper the control of voltage source
converter (VSC), as the DG front end, is in focus regarding the
power quality problems that could appear at the connection
point. The aims have been set to maintain a stable operation of
the DG in grid connected operation. The paper describes a
control strategy that is used to implement constant load
current when the load is connecting the renewable energy
resources. This paper proposes a constant voltage current
control method for a grid connected distributed power
generation.
A Simulink based model is developed and the simulation
results for the proposed model are obtained by using MAT
LAB.

Quality of power has always been an area of interest and needs continuous improvement for transmission and distribution system. In this paper the power quality issues viz. sag and swell are being analyzed for a distribution network. The effectiveness of DSTATCOM has been explored so that these above said power quality issues are mitigated up to a considerable extent. The performance of the device is examined when connected in shunt to a power distribution system. The results obtained validate a good performance of the model developed and high usefulness of the device to mitigate problems introduced. All simulations have been performed using MATLAB.Further the same system is analyzed for voltage sag conditions with and without DSTATCOM.

- by FOREX Publication and +1
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- Voltage sag, Dstatcom, Power Quality Improvement, Voltage Swell

"In this paper an MPPT technique is applied in grid connected PV system to harness maximum available power available from sun. The shortcomings of current inverter functions which link PV systems to the utility network are becoming transparent as PV penetration levels continue to increase. In this paper an analysis of solar system connected with the grid has been done.The system is subjected with two types of perturbations, i.e. variable load and the variable irradiance level which changes the output of the solar system. The design, modeling, and analysis of a grid-tied PV system are performed in the MATLAB software simulation environment. Solar cell works on the principle of photo voltaic effect, which has nonlinear voltage and current characteristics. These characteristics are improved with the help of maximum power point tracking (MPPT) controller. MPPT controller helps to feed the inverter with maximum power from the solar system. Results indicate that in the presence of grid disturbances the inverter can react dynamically to help restore the power system back to its normal state. A harmonic analysis was also performed indicating the inverter under study met the applicable power quality standards for distributed energy resources. Rajbir Sood | Geena Kalpesh""THD Reduction and Power Quality Improvement in Grid Connected PV System"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-1 | Issue-4 , June 2017, URL: http://www.ijtsrd.com/papers/ijtsrd173.pdf
Article URL: http://www.ijtsrd.com/engineering/electrical-engineering/173/thd-reduction-and-power-quality-improvement-in-grid-connected-pv-system/rajbir-sood"

Objective of research is to analyze the influence of the photovoltaic (PV) generator installation to power quality on distribution network. There are two models of load distribution network, namely industrial and residential costumers distribution network. Reseach show that the value of bus voltage THD on distribution network of industrial and residential customers are still under of voltage THD limit recomended by IEEE 519-1992 equal as 5%. The majority of the value of TDD conductor in two models of the distribution network is under the limit conductor current TDD recommended by IEEE 519-1992. In network industries and residential customers, the more number of PV plants installed, then the value of current harmonic (TDD) at PCC bus will be even greater. The most value of conductor current TDD average generated by conductor that is connected directly to the PV generator bus The using of single tuned passive filter able to improve THD Bus and TDD conductor which still does not meet the standart requirements.

- by Amirullah Amirullah
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- Power Quality Improvement

In this paper, voltage sag compensation of point of common coupling (PCC) using a new structure of fault current limiter (FCL) is proposed. The proposed structure prevents voltage sag and phase-angle jump of the substation PCC after fault occurrence. This structure has a simple control method. Using the semiconductor switch (insulated-gate bipolar transistor or gate turnoff thyristor at dc current rout leads to fast operation of the proposed FCL and, consequently, dc reactor value is reduced. On the other hand, the ...

Power quality was always a major concern in designing an electric supply system for railways. Since electric railcars are usually single-phase loads, they draw high amounts of negative sequence component of currents, in addition to harmonic contents and transient currents. Therefore, many compensation methods were examined to improve the power quality indices. The active power quality conditioner (APQC) can be considered as an ideal compensator for high-speed railway, which contains a three-phase converter connected to the traction substation through a step-down transformer. However, with the growth of railway loads, the nominal rating of the solid-state high-frequency switches of APQC increases seriously, which in turn, results in an exponential growth of the cost of power-electronic switches. Therefore, for a very high-capacity railway system, it is not economic to apply an APQC. As a solution, a combination of APQC with the static VAr compensator is proposed in this study, which reduces the rating of APQC, and improves the power quality of the system. Simulation results validate the pre-defined hypothesis. Moreover, the performance of APQC depends on the DC-link operation, for which genetic-algorithm optimisation has been applied to obtain an optimum design of a stable DC-link voltage.

Abstract. The present paper describes a shunt active power filter with a control system based on the p-q theory, and studies its performance through simulation results obtained with different types of loads. It is explained, in a brief form, the p-q theory and its application in the control of a shunt active power filter. Matlab/Simulink was the simulation tool, used in the study, development, and performance evaluation of the shunt active power filter controller. The simulations were carried out for different loads, of linear and non-linear types. The shunt active power filter allows compensating harmonic currents, reactive power, unbalanced loads, and zero-sequence currents, presenting a good dynamic and steady-state performance, as it can be observed in the simulation results. Key words

- by Emílio Couto
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- Control system, Computer Simulation, Reactive Power, Steady state
- by Pramod D'Sa
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- Power Quality Improvement, Harmonics, Uninterrupted Power Supply, DAQ system

Renewable energy sources (RES's) is the major source of electrical energy in future, the available renewable energy systems are solar, wind, fuel cell out of these solar system is most popularly used because this source hugely available in nature, this renewable energy source (RES) is most in demand for agricultural, industrial applications. In the agricultural field renewable energy source (RES) is feeding the motor, to have high efficiency for the motor. Motor is design for high voltage, where as to have high efficiency for solar system it is designed for low voltage. SO we need low voltage to high voltage converter. Various high voltage gain dc-dc converters are proposed in the literature out of those hybrid boost converter is chosen because of its simplicity and high voltage gain. This paper mainly proposes the integration of PV system with dc-dc converter and dc-ac inverter feeding an induction motor drive. The converter is controlled on closed loop to maintain output voltage constant. Even inputs sun radiations are varying. A Matlab/ Simulink models are developed for high gain dc-dc converter drive applications.

- by Kranthi Kumar
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- Power Quality, Power Quality Improvement

Passive filters are commonly used for harmonic mitigation and power factor correction in industrial power systems supplying non-linear loads. This paper firstly employs optimal design of two damped double-tuned filter schemes to minimize the filter and system's line loss while the individual and total harmonic distortion limits of the IEEE 519 standard and desired interval of the displacement power factor as constraints. For the solution of the formulated multi-objective optimization problem, Non-Dominated Sorting Genetic Algorithm (NSGA-II) is used. The results show that both schemes have the same fundamental frequency reactive power compensation, the line loss reduction and voltage regulation capabilities for the typical industrial power system with distorted background voltage and non-linear loads. On the other hand, it is also observed that the first studied scheme has considerable lower loss, while the second one has considerably higher current harmonic mitigation capability.

- by Shady H.E. Abdel Aleem and +1
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- Power Quality Improvement

Microgrid is cluster of distributed generation sources, storage systems and controllable loads. Microgrid can provide quality and reliable supply of energy to consumer. Microgrid can operate in both modes of operations that is grid connected mode and islanded mode. This implementation poses technical challenge of protecting the micro grid. Power quality, energy management, stability, power flow control, protection system and integration of various distributed generators are the major issues in the microgrid operation. This paper reviews various protection issues in micro grid, various protection schemes to overcome the protection issues are also discussed. Implementation of adaptive protection system using digital relaying and advanced communication is most successful method of the protection of micro grid.

- by ijaceee journal and +1
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- Power Quality, Distributed Generation, Flow Control, Microgrid

This paper presents the electrical system factors having an influence on the work efficiency and performance of the LC passive harmonic filters (PHFs). Such filters are very often used in industries for the purpose of harmonics mitigation and reactive power compensation. Before their installation in the electrical system, many investigations should be performed in order to ensure their good design as well as work efficiency after connection. In this paper, the factors having an influence on the PHFs work efficiency and performance, such as the grid short-circuit power, primary grid voltage spectrum (voltage measured at the PCC before the filter connection), load reactive power and current characteristic harmonics, manufacturer filter parameters tolerance and filter-detuning phenomena are investigated. Most of the quoted factors are mentioned in the literature, but the novelty of this paper is that, based on the case study example of the single-tuned filter investigated in the laboratory, the influence of those factors on the filter work efficiency are demonstrated, and some solutions and recommendations are proposed. The studies are focused on the design of the single-tuned filter in the laboratory, and some simulation results are presented as well.

- by Chamberlin Azebaze and +1
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- Smart Grid, Power Quality Improvement, Shunt Active Power Filter, Shunt Passive Filters,

“Electric Power Quality (EPQ) is a term that refers to maintaining the near sinusoidal waveform of power distribution bus voltages and currents at the rated magnitude and frequency.” The power quality is basically customer-centric. The increased focus on utilities toward maintaining reliable power supply by employing power quality improvement tools has reduced the power outages and blackout considerably. Good power quality is the characteristic of a reliable power supply. Low power factor, harmonic pollution, load imbalance, fast voltage variations are some common parameters which are used to define the power quality. If the power quality issues are not checked it will lead to a high electricity bill, the high running cost in industries, malfunctioning of equipment, challenges in connecting renewables. Capacitor banks, FACTS devices, harmonic filters, SVC’s, STATCOM are the solutions to achieve power quality. This paper presents the STATCOM system with the BESS and studies the impact on the power quality in a system which consists of the wind turbine generator, nonlinear load, hysteresis controller for controlling the operation of STATCOM and grid. The model is simulated in the MATLAB/Simulink. This scheme mitigates the power quality issues, improves voltage profile and also reduces harmonic distortion of the waveforms. BESS level out the imbalances caused by real power due to the intermittent nature of wind power available due to varying wind speeds.

The main dimension of the electricity quality is the supply continuity. It is evaluated by indices SAIDI (System Average Interruption Duration Index) and SAIFI (System Average Interruption Frequency Index). This paper presents a new implementation of the yardstick competition that combines two Data Envelopment Analysis models (DEA) to set the continuity standards for the electricity distribution utilities and their groups of consumption units. The approach has two stages. First, a classical DEA model performs a comparative analysis between utilities to define global continuity standards for each utility; next, based on global standards, a model for resource allocation based on DEA establishes the local continuity standards for groups of consumption units in the same utility. Local standards for the consumption units groups of the main distribution utilities in the Rio de Janeiro State are presented.

- by Luiz da Costa Laurencel and +1
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- Electrical Engineering, Energy Economics, Quality Management, Data Analysis (Engineering)

Parallel connections of inverters are being used in medium and high power applications. They are used to increase the output power and also to enhance a reliable source of power especially to critical loads. In this project various modulation techniques are proposed to analyse the performance of the inverter, minimize the output voltage THD, enhance the output voltage as well as eliminate the circulating current between the inverters that may flow as a result of their interaction. A three phase induction motor is used as a load. The modulation techniques with better performance among the three modulation strategies adopted in this work is selected based on the harmonic spectrum and the r.m.s output voltage, in order to control the speed of the machine for use in variable speed application. The speed can be controlled by varying the applied voltage, as already known that the starting torque is low when the voltage is low. Thus, even when the voltage is sufficient to achieve a running torque the machine may not start. The methodologies adopted are: the carrier phase shifted sinusoidal PWM (cps-spwm), third harmonic injection PWM and the SPWM with zero sequence signals. The system was simulated using matlab/simulink and the results was analysed and discussed.

This work introduces new technique named
Reference Voltage Compensation in conjunction with
STATCOM based on Proportional Integral and Derivative
control action which reduces much the transient peak and
settling time of the voltage and reactive power output
which were still present after application of the statcom.
In this work the proposed PID based Reference Voltage
compensation has been used to damp out the oscillations
of multi-machine power system and regulate the bus
voltage at which the STATCOM is connected and
maintain the reactive power. The results found for the
cases without STATCOM, with STATCOM and
STATCOM with RVC has been studied for various load
capacities, various load switching timings and faults of
different periods at various timings. It has been found that
the RVC using PID control concept has proved to have an
excellent performance over the other similar techniques in
the improvement of power system stability by reducing
settling time and peaks of transient oscillation due to
faults and load switching and improving pf thereby
increased system life.

- by Umesh Kumar Soni
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- Power System, Power system stability, Power Quality Improvement

In this paper, we present the effectiveness of using dynamic voltage restorer (DVR) in order to mitigate power quality disturbances like voltage sag, swell, short interruption, imbalance and fluctuation in three-phase distribution networks. This work investigates a basic architecture of DVR comprising phase locked loop (PLL) and proportional integral (PI) compensator as control elements and super capacitor as the energy storage device for high power density applications. Super capacitor is superior to the conventional battery storage systems in regard to highly efficient performance during long term and short term disturbances. Phase modulator is used to generate discrete pulse width modulation (PWM) switching signals for an IGBT based voltage source converter. The total harmonic distortion (THD) values during voltage disturbance events are computed considering with and without compensation cases. The performance evaluations of the proposed system are carried out in MATLAB/Simulink ® and the results corroborate the efficacy of the presented framework.

Power Quality problems in distribution systems can be solved by providing suitable shunt compensation, one such device is Distribution static compensator (DSTATCOM). Power quality issues generally arise due to high-energy demand loads such as pulse loads. In this paper, a new algorithm is proposed to generate reference voltage for a distribution static compensator (DSTATCOM) operating in voltage-control mode. To eliminate high-frequency switching components, three filter capacitors, one for each phase are to be connected in parallel with the DSTATCOM. Dead-beat controller is used to control and maintain the voltage across filter capacitor at the AC bus voltage. The magnitude of the bus voltage is chosen as nominal value, i.e., 1.0 p. u. To maintain the voltage across the DC storage capacitors constant, the required phase angle is obtained through a feedback loop. The proposed scheme ensures unity power factor (UPF) across the load terminals during nominal operation which is not possible in the traditional method. The compensator injects small currents thereby reduces the losses in the feeder and also in the voltage source inverter. The state-space model of DSTATCOM is incorporated with the deadbeat predictive controller for fast load voltage regulation during voltage disturbances. DSTATCOM here proposed provides power factor correction, harmonic elimination and thus tackles power-quality issues. The simulation results in MATLAB /SIMULINK platform are presented for the load balancing and voltage regulation of the same using the fuzzy logic controller.

- by editor jst
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- Power Quality Improvement

Distribution Generation plays a significant role in remote areas where the utility grid is affected and initializing by renewable energy sources to acquire the sufficient power demand. In distribution system, it is very exigent consumer related concern which is confronted due to mis-operation of massive non-linear load apparatus. A multi-functional distributed static compensator incorporates the best choice for enhancing the power quality features with effective control scheme under rambled non-linear loads. Conventional control schemes are more adversed with greater switching losses due to extreme harmonic frequencies in a refernce current component. This paper proposes, a novel multi-objective fundamental reference current control scheme based multi-functional DSTATCOM furnishes the current harmonic compensation at PCC, reactive power compensation, power factor correction, active power exchanging, minimizing the switching losses, incredible efficiency and power factor correction. The validation of proposed multi-functional DSTATCOM with proposed control strategy under rated capacity of distribution generation is evaluated by using Matlab/Simulink platform and simulation results are presented.

Objective of research is to analyze the influence of solar irradiance and integration of photovoltaic (PV) generator to power quality of three phase grid on the constant temperature and load, based on changes in some level of integration of PV generator. Power quality aspects studied are fluctuation or changing, and harmonics of voltage and current on eight scenarios PV generator connected to three-phase grid, using passive filter circuit model double band pass (double tuned). Research shows that voltage and current values on the PCC bus before use double tuned passive filter on the condition only connect single generator is still stable. However, if the PV generator connected to the three phase grid, amounted to more than one generation, voltage and current grid becomes unstable (fluctuation). At the level of solar radiation remains, the greater number of PV generators connected to the grid three-phase, then the values of voltage and current THD increases. At the level of solar irradiance increases, average THD of voltage and current grid also increased. Avarage THD of voltage and current grid is reduced after double tuned passive filter installed. Therefore, double tuned passive filter able to improve profile of voltage and current THD grid as a result of the integration of a number of PV power generators in three-phase grid according IEEE Standard 519-1992.

- by Amirullah Amirullah
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- Power Quality Improvement

Non-linear loads induce harmonics in to the distribution system and causes disturbance in operation for other loads connected to the same distribution system. Also, use of fossil fuels creates pollution problems which are not acceptable globally now-a-days. This paper addresses the two mentioned issues utilizing renewable energy source for power generation at distribution level and using APF for harmonic mitigation in distribution system. Integrating renewable energy source generating active power requires a voltage source converter. The voltage source converter acts as an integrating converter and the same converter is used to mitigate harmonics in the distribution system acting as APF. APF is controlled by instantaneous active and reactive power (IARP) theory. PV system is considered in this paper as renewable source for power generation. Results were presented for the proposed work with and without integration of distributed generation for fixed and variable load conditions. The proposed work has been carried out using MATLAB/SIMULINK software.

- by Kranthi Kumar
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- Power Quality Improvement

In the age of fast evolution, software development project must accept many challenges of unpredicted requirements change and new technology environment. Software development processes should have adjustable and extendable features to meet the multifaceted needs of the users. Iterative and Incremental Development (IID) is a practical approach to overcome the various challenges of software development. However, continuous testing and building new versions need to spend more time and human resources that is a major obstacle of IID. The other, the iterative operations must have a sound communication skills. Lack of standard version control and intercommunication manner often lead to failure of software project. High quality Continuous Integration (CI) environment can effectively make up the defects of IID. In this paper, CI environment and advantages are deeply surveyed. In order to overcome the defects of IID, CI environment needs combine the perfect procedures and qualified tools, and concretely enhance the quality of CI environment. Based on the process quality measurement model, this paper proposes the Process Quality Improvement Mechanism (PQIM). Applying PQIM, in software development, the processes problems and the CI environment quality defects can identify timely and indeed revise to reduce the risk of CI environment.