New approach for estimation of harmonics in the electrical network (original) (raw)

A Review of Harmonics Detection and Measurement in Power System

International Journal of Computer Applications, 2016

A load is said to be "linear" when it draws a current from the supply which is proportional to the applied voltage (linear). And in the case of "non-linear" load, impedance changes with applied voltage. The current drawn from such non-linear load is also non-linear i.e. non-sinusoidal even when it is connected to a sinusoidal voltage source. Harmonic currents contents which are present in non-sinusoidal currents intermingle with the impedance of the power distribution system to create voltage distortion which affects the distribution system and the loads connected to it. The serious power-line pollution is a result of increasing use of power electronic systems and time-variant nonlinear loads in industry. Hence, power supply quality is degraded. It results in the reduction of system efficiency, apparatus overheating, and increase power. As the utilization of the number of harmonics-producing loads has increased over the years, it has become highly mandatory their influence and analysis when making any additions or changes to an installation. In this paper various harmonics detection and measurement techniques have been outlined.

Fourier Analysis for Harmonic Signals in Electrical Power Systems

Fourier Transforms - High-tech Application and Current Trends, 2017

The harmonic content in electrical power systems is an increasingly worrying issue since the proliferation of nonlinear loads results in power quality problems as the harmonics is more apparent. In this paper, we analyze the behavior of the harmonics in the electrical power systems such as cables, transmission lines, capacitors, transformers, and rotating machines, the induction machine being the object of our study when it is excited to nonsinusoidal operating conditions in the stator winding. For this, a model is proposed for the harmonic analysis of the induction machine in steady-state regimen applying the Fourier transform. The results of the proposed model are validated by experimental tests which gave good results for each case study concluding in a model proper for harmonic and nonharmonic analysis of the induction machine and for "harmonic" analysis in an electrical power system.

A New Method for Power Signal Harmonic Analysis

IEEE Transactions on Power Delivery, 2005

With the increasing use of nonlinear loads in power systems, the harmonic pollution becomes more and more serious. It is well known that fast Fourier transform (FFT) is a powerful tool for power signal harmonic analysis, but leakage effect, picket fence effect, and aliasing effect make FFT suffer from specific restrictions. In this paper, we proposed a new method for power signal harmonic analysis. The major components of this method are a frequency and phasor estimating algorithm, a finite-impulse-response comb filter, and a correction factor. We also combine other methods to enhance our performance, such as discrete Fourier transform and least square error (LSE) method. To verify this method, we provided the comparisons of this method with FFT. Index Terms-Fast Fourier transform (FFT), finite-impulse-response (FIR) comb filter, harmonic analysis.

Harmonics Analysis of Power Electronics Loads

International Journal of Computer Applications, 2014

The linear customer loads are now being dominated by sensitive and sophisticated non-linear customer loads with the growth in the power electronics and control system industries. This have a catastrophic impact on a power system and equipment: increasing harmonics "pollution". In this paper the modelling of power electronics loads used in domestic and small scale industrial distribution systems are discussed. Various domestic loads such as computer, fluorescent lamp, CFL lamp and small scale industry loads such as adjustable speed drive, arc welder and lift are modelled in PSCAD/EMTDC and then the harmonic analysis of these models are performed

Chapter 3 Fourier Analysis for Harmonic Signals in Electrical Power Systems

2019

The harmonic content in electrical power systems is an increasingly worrying issue since the proliferation of nonlinear loads results in power quality problems as the harmonics is more apparent. In this paper, we analyze the behavior of the harmonics in the electrical power systems such as cables, transmission lines, capacitors, transformers, and rotat‐ ing machines, the induction machine being the object of our study when it is excited to nonsinusoidal operating conditions in the stator winding. For this, a model is proposed for the harmonic analysis of the induction machine in steady‐state regimen applying the Fourier transform. The results of the proposed model are validated by experimental tests which gave good results for each case study concluding in a model proper for harmonic and nonharmonic analysis of the induction machine and for “harmonic” analysis in an electrical power system.

A Controlled Filtering Method for Estimating Harmonics of Off-Nominal Frequencies

IEEE Transactions on Smart Grid, 2012

The increasing use of power electronics in power systems causes a high injection of harmonic components which can in turn interfere with utility equipment and customer loads. Therefore, the correct estimation and measurement of harmonics have become an important issue. If the power frequency of the signal is steady and near the nominal value, the discrete Fourier transform (DFT) can be used and good estimation performance is achieved. However, there are considerable power frequency variations on isolated systems such as shipboard power systems, micro-grids and smart-grids. When these variations occur there may be significant errors in the estimates using the DFT. In order to deal with this problem, this work presents a novel technique based on demodulation of the power line signal and subsequent filtering for harmonics estimation. The main features of the proposed harmonic estimation technique are: precise and accurate estimation of harmonics of off-nominal frequencies and fast estimation of harmonics (about two cycles of the fundamental component). Simulation results show that the proposed technique performs well in comparison with the DFT and can be a good candidate to replace it in cases where the power frequency is subject to considerable variations. Index Terms-Controlled FIR filter, harmonics estimation, offnominal frequency. I. INTRODUCTION T HE increasing use of power electronic devices in power systems has been producing significant higher harmonic distortions, what can cause problems to computers and microprocessor-based devices, thermal stresses to electric equipments, harmonic resonances, as well as aging and derating to electrical machines and power transformers [1]-[4]. One of the most important problems that have been reported in the literature concerns the difficulty of the frequency control within the micro-grids and the increase of the total harmonic distortion. These two factors may negatively impact on the protection system, power quality analysis and other intelligent electronic devices (IEDs), in which digital algorithms assume that the fundamental frequency is constant. Based on this fact,

Estimation and Filtering of Current Harmonics in Power System

2016

Now-a-days with the advancement of technology, the demand for electric power is increasing rapidly. Every equipment in the system needs power continuously for their operation. The performance of the equipment depends on the quality of power on which it is working. But the power quality depends on various factors. These factors include voltage & frequency variations, faults and line outages in the system. The reduction in power quality reduces the life and efficiency of the equipment of the system. To enhance the performance of not only the load but also the overall performance of the system these problems should be mitigated. Harmonics are the main outcome of the power quality problems. When these harmonics travel through the line in the system, it leads to the overheating of the equipment, insulation failure and vibrations of motor shaft. To overcome these problems harmonics are to be filtered. Many filter topologies were developed for this purpose. In this project a shunt active f...

Harmonics Detection and Measurement in Power System

Zenodo (CERN European Organization for Nuclear Research), 2020

In the present decade usage of nonlinear loads and power electronic device in the industry sector has been increasing. Due to this the harmonics in the system get affected more and it gets result in the nonlinear electric loads. Harmonics are determined to have tremendouss effects on power system, Equipment including Induction motor, Transformer, Conductors, Capacitor banks, Switchgearr, and Protective relay. The count of harmonics producing loads has been having the drastic effect over the years. Now it has been became increasingly necessary to detect them by making changes to a system installation. Aiming towards the Improvement of Power Factor and Elimination of Harmonics induced in the system due to non-linear loads. This method helps to improve power factor and eliminate harmonics, so the power fed to the loads will be of better quality. This will not only reduce the penalization over consumers but also lead to run the load to their maximum efficiency. Further, the circuit of PF correction & detection similarly the Harmonics measurement and correction simulations are presented over Proteus Software. This tool helps to carry out trial and error method of the circuits. The calculated values will be fed to the Controller circuit which carries out programmed operations to get the desired outputs which are displayed over the LCD.