File Name: power systems harmonics fundamentals analysis and filter design .zip
Harmonics In Power System Pdf.
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Nurul Azim Bhuiyan MSc. I am sincerely and heartily thankful to my project supervisor, Dr. Mohamed Darwish, for the support and guidance he showed me throughout my dissertation writing. I am sure it would have not been possible without his help.
Besides I would like to thank to my parents and my classmates boosted me morally and provided me great information resources. I would like to show my gratitude to my course director Dr. Gareth Taylor, Prof. Malcom Irving, Dr. Ahmed Zobaa for their valuable lecture which assisted me to complete the project successfully. The main intention of any electrical utility company is to deliver power with better quality.
By increasing the use of power electronic devices Non linear load , the power quality has been affected. One of the most important causes for improper power quality is power system harmonics. This has become a major issue for power quality problem and harmonic analysis needed to investigate in modeling components to minimize or remove this harmonics current or voltage.
In this project, power system harmonic analysis has been performed using ETAP software and described the whole process in details. First of all, a general load was modeled as a harmonic source to inject harmonic current through the power network. Then, to analyse the effect of harmonic current, Harmonic Load Flow analysis was performed and harmonic distortion identified.
To eliminate this harmonic distortion, different kinds of technique were followed. Those are harmonic filter designing, capacitor bank e. The overall results were discussed in details to measure the efficiency of that harmonic analysis. Figure 2. Figure 4. This goal is complicated by the fact that there are loads on the system that produce harmonic currents. These currents result in distorted voltages and currents that can badly impact the system performance in different ways.
Harmonics are the by-products of modern electronics. Sinusoidal voltages or currents having frequencies that are integer multiples of the frequency at which the supply system is designed to operate usually 50 or 60 Hz is called harmonics.
The large numbers of personal computers single phase loads , uninterruptible power supplies UPSs , variable frequency drives AC and DC or any electronic device using solid state power switching supplies to convert incoming AC to DC cause harmonics and make the voltages and currents distorted. Non-linear loads create harmonics by drawing current in rapid short pulses, rather than in a smooth sinusoidal manner. As increasing the amount of power generation from renewable energy sources, more power electronic devices are being added into the main grid, thus increasing the overall amount of harmonics into the main supply itself.
In western country, the majority of the renewable energy source is from wind energy. Other devices which depreciate in power quality of a network will majorly include devices such as saturated transformers, fluorescent lights, cycloconverters, arc furnaces etc.
The harmonics in the power network may result in resonance conditions in the power network and thus causing the deterioration of the power quality in the grid. The outcome of this harmonic resonance is that, it will generate highly rated circulating currents and voltages at the resonant frequency, which could cause power quality problems such as voltage sags, swells, flickers etc.
As a consequence of this harmonic distortion, the industrial plants may face pulsating torques in the rotor of the motor, or it may cause nuisance tripping of the smaller units that are associated in the plant site or.
These harmonics current that are being generated from harmonic source, is resulting in either current or voltage distortion for the entire power network. This noticeable fact has become a major issue for power quality problem and harmonic analysis needed to investigate how to minimise or remove these harmonics. Harmonic Analysis is used to identify harmonic problems, minimize nuisance trips, design and test filters, and identify potential violations of distortion limits.
Different kinds of power system software can be used to perform Harmonic Analysis on the power network. In this study, ETAP 7. ETAP is very user friendly software where key tools that are needed for efficient harmonic analysis are easy to operate to get better results. It is also proficient of depicting the consequences of implementing the required power network on real life. To accomplish this, the study undergoes a list of objectives as shown below:.
All of aforesaid key issues of the project will be analysed on adopting IEEE standard, where the Harmonic indices will be set accordingly in the software. For all of the objectives as told above will be carried on the basis of the two analytical methods. The Harmonic Load Flow study first conduct a load flow calculation at the fundamental frequency.
The result of the fundamental load flow sets the base for the fundamental bus voltage and branch currents which are used later to compute different harmonic indices.
Then, for each harmonics frequency at which any harmonic source exists in the system, a direct load flow solution is found by using the current injection method. The power station frequency scan program is the best tool to examine the system resonance problem. Because of the existence of both inductive and capacitive components in the system, at certain frequencies, resonance conditions might occur at some buses.
If the resonance occurs at a bus where a harmonic current is injected into the system, an over voltage and over current form will be observed. To fully understand the impact of this phenomenon, we need to consider two important things of power system harmonics. The first one is the nature of harmonic-current producing loads non-linear loads and the second one is the way in which harmonic currents flow and the development resulting harmonic voltages.
In other words, the current waveform will have the same waveform as the voltage. Some examples of linear loads are motors, heaters and incandescent lamps. The harmonics in linear loads are fractionally lower and they can be easily neglected. On the other side, the current waveform on a non-linear load is not the same as the voltage waveform. Some examples of non-linear loads are rectifiers power supplies, UPS units, discharge lighting , adjustable speed motor drives, ferromagnetic devices, DC motor drives and arcing equipment.
The current waveform from non-linear loads is not sinusoidal but it is periodic, Periodic waveforms can be found mathematically as a series of sinusoidal wave shapes that have been added together. The sinusoidal components are the integer multiples of the primary where the primary in the UK is 50 Hz and the additional elements turned to harmonics. Here the third harmonic will have a frequency of three times that is Hz.
A symmetrical waves contain only odd harmonics and un-symmetrical waves contain even and odd both harmonics. In a symmetrical wave the positive portion is identical to the negative portion of the wave. On the other hand, an un-symmetrical wave contains a DC component or the load is such that the positive portion of the wave is different than the negative portion.
The example of an un-symmetrical wave is a half wave rectifier. In power system most of the elements are symmetrical. They produce only odd harmonics and have no DC offset. Arc furnaces are a common source of even harmonics but they are notorious for producing both even and odd harmonics at different stages of the process.
From the given figure below, it can be seen that, when a non-linear load draws current, that current passes through all of the impedance that is between the load and the system source.
As an effect of the current flow, the harmonic voltages are produced by impedance in the system for each harmonic. The magnitude of the voltage distortion depends on the source impedance and the harmonic voltages produced from the power network.
If the source impedance is low then the voltage distortion will be low. In conclusion it can be said that, the harmonic currents can have a significant impact on electrical distribution systems and the facilities that they feed. The increment of renewable power generation will create a major impact on the power network.
Power system harmonic analysis needed to improve the power quality by installing appropriate devices. In addition, identifying the size and location of non-linear loads should be an important part of any maintenance, troubleshooting and repair program. Different filters are named according to the frequency of signals they allow to pass through them. The Low-pass filters allow only low frequency signals to pass, while the High-pass filters allow only high frequency signals to pass through, and Band-pass filters allow signals falling within a certain frequency range to pass through.
Simple First-order passive filters 1st order can be made by connecting together a single resistor and a single capacitor in series across an input signal, Vin with the output of the filter, Vout taken from the junction of these two components. Depending on the way of connection the resistor and the capacitor with regards to the output signal determines the type of filter construction resulting in either a Low Pass Filter or a High Pass Filter.
A simple passive Low Pass Filter can be made by connecting a single Resistor with a single Capacitor together in series as shown below. This type of filter is known as a "first-order filter" or "one-pole filter" because of its "one" reactive component in the circuit, the capacitor. A low-pass filter passes low frequency signals, and rejects signals at frequencies above the filter's cut-off frequency.
Only passes signals above the selected cut-off point. By connecting or "cascading" together a single Low Pass Filter circuit with a High Pass Filter circuit, another type of passive RC filter can be produced that passes a selected range or "band" of frequencies, can be either narrow or wide while attenuating all those outside of this range.
This new type of passive filter arrangement produces a frequency selective filter known commonly as a Band Pass Filter. Its modular functionality can be modified to fit the needs of any company, from small to large power systems. In order to perform harmonic analysis, ETAP software is chosen for the project. This is user friendly software and easy to model harmonic sources. ETAP can perform some other types of analysis as given bellow: .
Engineers use ETAP in thousands of companies and electric utilities worldwide in the design, analysis, maintenance, and operation of electrical power systems. A unique feature of this software is that it has got centralised data base system in which all the analysis that has been conducted gets stored in and later this data can be extracted using Microsoft Access with ease.
ETAP Real-Time is a suite of software through continuous monitoring, simulation, and optimization of electrical, process, manufacturing, and management systems that are in place, ETAP can maximize the entire production process, reduce losses, and increase profits. ETAP Star device coordination is a new idea in performing steady-state and dynamic device coordination, selectivity protection, and testing. This is achieved by utilizing intelligent one-line diagrams, widespread device libraries, and an integrated three- dimensional database.
ARTTS can test different kinds of protective relays including distance relays, as well as energy meters and transducers. ARTTS power system tools utilize advanced hardware and software technologies for testing, simulating, and calibrating relays and comparing the real test response with the manufacturer published data.
Ground Grid Systems module enables engineers to quickly and exactly design and analyze ground protection. Advanced 3-D technology integrates with one-line diagrams, allowing engineers to visualize their ground systems and seamlessly employ short circuit results.
Power systems harmonics Analysis and Filter Design. Wakileh, G. Wakileh Solution Manual Principles of Aiming at a better understanding of power system harmonics, this text presents a discussion of Download Errata 1 PDF
Par boland reginald le jeudi, juin 6 , - Lien permanent. Wakileh, G. Machinery and Power System Fundamentals. Systems Harmonics : Fundamentals, Analysis and Filter. The electric utility's increasing use of power factor correction capacitor banks and the industry's widespread application of power-electronic converters have set the. Fundamentals, Analysis and Filter Design. Powell's City of Books is an independent bookstore in Portland,.
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Wakileh has some strong factors for you to read. This publication is quite suitable with what you require now.
It seems that you're in Germany. We have a dedicated site for Germany. The electric utility's increasing use of power factor correction capacitor banks and the industry's widespread application of power-electronic converters have set the basis for, recently, paying considerable attention to the issue of power system harmonics.
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