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1
Holtsmark, Nathalie Marie-Anna. "Reactive Power Compensation using a Matrix Converter." Thesis, Norwegian University of Science and Technology, Department of Electrical Power Engineering, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-10040.
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<p>This Master's thesis investigates a new application for the matrix converter: Shunt reactive power compensation. The suggested Matrix Converter-based Reactive power Compensation (MCRC) device is composed of a matrix converter, which input is connected to the grid and an electric machine at the output of the converter. The reactive power flowing in or out of the grid can be regulated with the matrix converter by controlling the magnitude and/or phase angle of the current at the input of the converter. The matrix converter has no bulky DC link capacitor like traditional AC-DC-AC converters. The thought electric machine is a Permanent Magnet (PM) synchronous machine which is compact as well, yielding an overall compact device. The main focus of the thesis is to evaluate the reactive power range that the MCRC device can offer. The reactive power range depends mainly on the modulation of the matrix converter. Two different modulation techniques are studied: the indirect virtual space vector modulation and the three-vector-scheme. The indirect space vector modulation can provide or draw reactive power at the input of the matrix converter as long as there is an active power flow through the converter that is different from zero. For pure reactive power compensation the indirect space vector modulation cannot be used and the three-vector-scheme must be used instead. Both modulation techniques are presented in details as well as their reactive power compensation range. To verify the reactive power capabilities of the device, three different simulation models are built in MATLAB Simulink. The first simulation model represents the MCRC device with the matrix converter modulated with the indirect space vector modulation. The second model represents also the MCRC device with the matrix converter modulated with the three-vector-scheme. In both model the PM machine is represented by a simple equivalent circuit. Simulations done with both models show a good accordance between the theoretical analysis of the device and the experimental results. The last simulation model features a simplified version of the MCRC system connected to a grid where a symmetrical fault occurs. The MCRC proves to be efficient in re-establishing the voltage to its pre-fault value.</p>
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Prato, Michael V. "Reactive power compensation using an energy management system." Thesis, Monterey, California: Naval Postgraduate School, 2014. http://hdl.handle.net/10945/43982.
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Approved for public release; distribution is unlimited<br>A significant contributor to higher energy costs and reduced energy efficiency is the reactive power demand on the grid. Inductive power demand reduces power factor, increases energy losses during transmission, limits real power supplied to the consumer, and results in higher costs to the consumer. Compensating for a reactive power demand on the grid by providing reactive power support to the power distribution system creates energy efficiency gains and improves cost savings. One method of compensating for reactive power is by incorporating an energy management system (EMS) into the power distribution system. An EMS can monitor reactive power requirements on the grid and provide reactive power support at the point of common coupling (PCC) in the power distribution system in order to increase energy efficiency. The use of an EMS as a current source to achieve a unity power factor at the grid is demonstrated in this thesis. The power factor angle was determined using a zero-crossing detection algorithm. The appropriate amount of compensating reactive current was then injected into the system at the PCC and controlled using closed-loop current control. The process was simulated using Simulink and then validated in the laboratory using the actual EMS hardware.
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Welgemoed, Frans Marx. "Shunt reactive compensation of voltage dips and unbalance." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5315.
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Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2010.<br>ENGLISH ABSTRACT: The use of power electronic converters provides a more efficient, accurate and
dynamic solution to reactive compensation. In this thesis the application of power
electronic converters to shunt reactive compensation will be discussed. In particular
voltage dips and voltage unbalance are considered as both can be mitigated by
means of shunt reactive compensation.
A pre-existing uninterruptible power supply is adapted to operate as a shunt reactive
compensator. The uninterruptible power supply consists of a 250 kVA three phase
voltage source inverter. The modifications are limited to software and control
algorithms that do not alter the normal operation of the uninterruptible power supply.
Control algorithms are designed and discussed in detail. A typical double loop
control strategy is implemented on the power electronic converter. The inner loop
consists of a dead-beat current controller. The outer loop consists of three
proportional and integral controllers controlling the DC-bus voltage, AC voltage and
voltage unbalance respectively.
Voltage dips and unbalance are compensated for using only reactive power. Focus
is placed on producing a result can be used easily in practice.<br>AFRIKAANSE OPSOMMING: Drywings elektroniese omsetters wat gebruik word vir newe reaktiewe kompensasie
lewer meer effektiewe, akkurate en dinamiese resultate. In hierdie tesis word die
toepassing van drywings elektroniese omsetters vir newe reaktiewe kompensasie
bespreek. Daar word meer spesifiek na spannings duike en spannings wanbalans
gekyk aangesien albei met newe reaktiewe kompensasie verminder kan word.
’n Bestaande nood kragbron is aangepas om as n newe reaktiewe kompenseerder te
funksioneer. Die nood kragbron bestaan hoofsaaklik uit ’n 250 kVA drie fase
omsetter spanningsbron. Die aanpassings is beperk tot sagteware en beheer
algoritmes wat nie die oorspronklike funksionaliteit van die nood krag bron beinvloed
nie. Beheer algoritmes word ontwerp en deeglik bespreek. ’n Tipiese dubbel lus
beheer strategie word op die drywings elektroniese omsetter toegepas. Die binnelus
bestaan uit ’n voorspellende stroom beheerder. Die buite-lus bestaan uit drie
proportioneel en integraal beheerders wat onderskeidelik die GS-bus spanning, WS
spanning en spanning wanbalans reguleer.
Spannings duike en wanbalans is verminder deur slegs reaktiewe drywing te gebruik.
Die doel was ook om ’n prakties bruikbare resultaat te lewer.
4
Singer, Amr. "External Reactive Power Compensation of Permanent Magnet Synchronous Generator." Doctoral thesis, Universitätsbibliothek Chemnitz, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-69333.
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This research work focuses on the reactive power compensation of the permanent magnet synchronous generator (PSG) in wind power plants. PSG feeds a fixed voltage dc grid through a rectifier bridge. In variable speed operation, the PSG will be able to build torque only in small speed range. This is due to the fixed magnet of the PSG. External reactive power compensation provides an attractive solution to overcome this problem. Different reactive power compensation configurations were examined. Statics synchronous series compensation and a shunt passive filter were chosen as a compensation method. Simulation and implementation of small wind power plant were performed. The wind power plant consists of the synchronous generator, inverter, rectifier, coupling transformers and shunt passive filter. The experimental results agree to the proposed theory and simulation results<br>Der Schwerpunkt meiner Promotion ist die Blindleistungskompensation bei einem permanenterregten Synchrongenerator. Der Synchrongenerator speist das Gleichsspannungsnetz über ein Gleichrichter. In der Drehzahlvariablen Betriebsverhalten können Nachteile auftreten. Die Folge ist, dass bei konstanter Gleichspannung und fester Erregung durch die Permanenterregung nur ein sehr kleiner Drehzahlbereich mit vernünftiger Drehmomentausbeute bedienbar ist. Ein möglicher Ausweg wäre eine variable Kompensationsspannung. Verschiedene Kompensationsverfahren wurden untersucht. Ein Series Active Filter und ein Shunt Passive-Filter wurden als Blindleistungskompensation gewählt. Im Rahmen meiner Dissertation beschäftige ich mich mit dem Aufbau und der Simulation einer Windkraftanlage. Diese besteht aus einem permanenterregten Synchrongenerator, einem Wechselrichrter, einem Gleichrichter, drei Transformatoren und einem passiven Filter. Das Versuchsergebnis zeigt, dass die Theorie mit der Simulation übereinstimmt
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Hu, Lihua. "The application of reactive power compensation to ac electrified railway systems." Thesis, Staffordshire University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282965.
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Raju, N. Ravisekhar. "A decoupled converter topology for active compensation of power systems /." Thesis, Connect to this title online; UW restricted, 1996. http://hdl.handle.net/1773/5847.
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Trainer, D. R. "The application of self commutated converter circuits for static reactive power compensation." Thesis, Staffordshire University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244432.
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Yu, Henry Hon-Kit. "Computer aided design of static reactive compensation for high voltage power systems." Thesis, University of Sunderland, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293552.
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This thesis describes the development of a detailed set of step-by-step SVC system design procedures which allow manufacturers and operators to plan and develop optimum SVC systems for a given a.c. power transmission system. The validity of a typical svc system designed using the suggested procedures is investigated. The internationally recognised software package EMTP has been used as the primary Research tool, and principal features of this software, including those observed in the Research study also forms part of the discussion in the thesis. Previous conventional approaches to SVC simUlation have been restricted to simplified system models, and have only provided partial solutions to the design problem. In contrast, a detailed representation of three phase SVC systems using a time-domain approach is used in this research study in order to formulate a comprehensive design methodology. The SVC considered is for high voltage transmission applications, and is the TSC-TCR-FC type. A new optimisation program termed "OPTI-SVC" has also been developed to assist the SVC system design process. The system compensation limits must first be derived, and then for given equipment costs and system harmonic constraints, the program evaluates the optimum arrangement of the SVC primary system. Although certain simplifying assumptions are made and only those factors that can be taken into account analytically are considered, the program uses a worst case design philosophy in order to ensure acceptable performanceIn particular, Cost of the the program can minimise either the total svc system or the total harmonic voltage produced in the transmission system. In order to derive optimum control system settings, in particular for the SVC regulator, a structured trial and error approach has been developed. wi th the aid of the Astrom relay tuning technique, a good first estimation on optimum regulator settings for a given a.c. system condition can be obtained. The results are then systematically trimmed until a satisfactory system response is achieved. A three phase SVC system has been designed using the suggested approaches and applied to a generator fed transmission system. Realistic system data has been supplied by NEI Reyrolle Technology Limited. Simulated performance tests carried out demonstrate the correct functioning of the svc system against general accepted criteria, and hence the validity of the design procedure is established. As a primary research tool, the software EMTP has been proved to be very versatile although not user-friendly. Significant observations regarding the use of EMTP that are necessary to assist general users of the software package, are also revealed in the research study.
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Bilgin, Faruk Hazim. "Design And Implementation Of A Current Source Converter Based Statcom For Reactive Power Compensation." Phd thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608308/index.pdf.
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This research work is devoted to the analysis, design and development of the first medium power Current-Source Converter (CSC) based distribution-type Static Synchronous Compensator (D-STATCOM) with simplest converter topology and coupling transformer connection. The developed CSC-D-STATCOM includes a +/-750kVAr full-bridge CSC employing Selective Harmonic Elimination Method (SHEM), a 250kVAr low-pass input filter at 1kV voltage level, and a &<br>#916<br>/Y connected
coupling transformer for connection to medium-voltage load bus. The power stage of CSC is composed of series connection of natural air-cooled high-voltage IGCT
switched at 500 Hz for the elimination of four lowest current harmonic components (5th, 7th, 11th, 13th), and optimized fast recovery high voltage diode in each leg. Reactive power control is achieved by applying the phase shift angle control at fixed modulation index, which is implemented digitally on a DSP microcontroller.
The developed system has been implemented for compensation of rapidly varying reactive power demand of coal mining excavators in Turkish Coal Enterprises. The
field test results have shown that the proposed CSC D-STATCOM serves as a technologically new full substitute of conventional Voltage-Source Converter based
D-STATCOM having complex transformer connections in view of relatively fast response in reactive power compensation, very low total demand distortion factors, complying with the IEEE Std. 519-1992 even for the weakest power systems, and
acceptable efficacy figures.
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Bicer, Nazan. "A Current Source Converter Based Statcom For Reactive Power Compensation At Low Voltage." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/2/12612007/index.pdf.
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This research work is devoted to the analysis, design and development of the Current-Source Converter (CSC) based distribution-type Static Synchronous Compensator (D-STATCOM) for low-voltage applications in reactive-power control in order to achieve i) faster transient response in reactive-power control, ii) lower current harmonic distortion, iii) lower power losses and iv) minimum storage elements in comparison with conventional solutions. The developed CSC-D-STATCOM includes a low-pass input filter and a three phase forced-commutated CSC which is composed of six insulated gate bipolar transistors (IGBT) with built-in series diodes. The analysis and the control of the CSC-D-STATCOM are carried out in dq-synchronous reference frame in order to obtain the reference current waveform which is to be generated by switching the IGBTs at 3kHz with the use of space vector modulation.
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Spro, Ole Christian B. "Reactive Power Compensation and Active Filtering Capabilities of the Step-down AC Chopper." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elkraftteknikk, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-23617.
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The Step-down AC Chopper (hereby referenced as "AC Chopper") has been presented in recent academic papers as a possible solution for reactive compensation. The goal of this project was to investigate and evaluate the topology to see if the praise could be justified. In addition, this project set a goal to take the research one step further by investigating if the uses of the AC Chopper could be expanded to include active filtering. The ability of the AC Chopper converter to produce harmonic current was investigated. This was the first step in developing the AC Chopper's active filtering functionality. Theorems were developed and simulations were performed with both open and closed loop control. The results show that using the AC Chopper to produce harmonic current is very difficult if not impossible. This is due to intrinsic characteristics of the topology which leads to the converter producing multiple harmonics for a single control input frequency. Hence it was concluded that the AC Chopper is not fit for performing active filtering and that the results do not support continuing any further research on the AC Chopper's filtering capabilities.A prototype of the converter was developed and built to compare the simulations against real observed behavior. The development process has been well documented in this thesis. Open loop control of the prototype was successfully implemented. The results show a good relation between the theory and the measured values. There are certain challenges connected to the realization of the AC Chopper, and the ways of dealing with these challenges have been described herein. The topology was also compared to available technology to evaluate the competitiveness regarding reactive compensation at fundamental frequency. The AC Chopper was not found advantageous compared to the VSI, a modern available solution. The efficiency of the AC Chopper has been found to be slightly higher in simulation, but this has yet to be validated with tests on real prototypes. In addition to lacking the filtering capabilities, the AC Chopper has other disadvantages including expensive components and greater volume. Together the findings in this report suggests that the AC Chopper should be limited to use in single phase systems for reactive compensation at fundamental frequency in open loop control.
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Etminan, S. "Simulation of high-speed static reactive compensation for suppression of power system disturbances." Thesis, University of Sunderland, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.253748.
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Pilgrim, J. D. "Genetic algorithms for optimal reactive power compensation planning on the national grid system." Thesis, University of Bath, 2002. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.631723.
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Popek, Jiří. "Návrh koncepce kompenzace jalového výkonu v průmyslové síti." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219402.
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This thesis is about reactive power compensation in industrial network. Task is design reactive power compensation devices, so that the power factor, which is main indicator of power quality, was within the limits required by the distributor. This is applied to wholesale customers of electrical energy. Reactive power consumed by appliances increased the current that flows through the network, transmission losses and voltage drop. Reactive power compensation is a measure reducing load current and ohmic losses in a supply line. Given that the compensation is one of the significant cost-saving measures in electric power distribution. Distributor requires electric power consumption with a lagging power factor in the range from 0,95 to 1. Other values of power factor are penalized.
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Paaso, Esa A. "Coordinated Voltage and Reactive Power Control of Power Distribution Systems with Distributed Generation." UKnowledge, 2014. http://uknowledge.uky.edu/ece_etds/40.
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Distribution system voltage and VAR control (VVC) is a technique that combines conservation voltage reduction and reactive power compensation to operate a distribution system at its optimal conditions. Coordinated VVC can provide major economic benefits for distribution utilities. Incorporating distributed generation (DG) to VVC can improve the system efficiency and reliability. The first part of this dissertation introduces a direct optimization formulation for VVC with DG. The control is formulated as a mixed integer non-linear programming (MINLP) problem. The formulation is based on a three-phase power flow with accurate component models. The VVC problem is solved with a state of the art open-source academic solver utilizing an outer approximation algorithm. Applying the approach to several test feeders, including IEEE 13-node and 37-node radial test feeders, with variable load demand and DG generation, validates the proposed control.
Incorporating renewable energy can provide major benefits for efficient operation of the distribution systems. However, when the number of renewables increases the system control becomes more complex. Renewable resources, particularly wind and solar, are often highly intermittent. The varying power output can cause significant fluctuations in feeder voltages. Traditional feeder controls are often too slow to react to these fast fluctuations. DG units providing reactive power compensation they can be utilized in supplying voltage support when fluctuations in generation occur. The second part of this dissertation focuses on two new approaches for dual-layer VVC. In these approaches the VVC is divided into two control layers, slow and fast. The slow control obtains optimal voltage profile and set points for the distribution control. The fast control layer is utilized to maintain the optimal voltage profile when the generation or loading suddenly changes. The MINLP based VVC formulation is utilized as the slow control. Both local reactive power control of DG and coordinated quadratic programming (QP) based reactive power control is considered as the fast control approaches. The effectiveness of these approaches is studied with test feeders, utility load data, and fast-varying solar irradiance data. The simulation results indicate that both methods achieve good results for VVC with DG.
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Prasai, Anish. "Direct dynamic control of impedance for VAR and harmonic compensation." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42816.
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Reactive power is critical to reliable operation of the modern AC power system. There is a plethora of motor-loads, transformers, and power-electronic loads connected to the power grid, which consume reactive power for normal operation. Transmission lines also consume reactive power when they are loaded above their surge impedance loading (SIL). Reactive power can exact opportunity cost due to reduced capacity of the lines to carry real power, which in turn lowers revenue. Most transmission owners (TOs) levy large penalties against load serving entities (LSEs), industrial facilities, and other end-use customers, who consume more than their allotted amount, as measured by their power factor. These penalties are to incentivize their customers to meet their reactive power needs locally as well as to recuperate the TOs' financial losses.
Harmonic pollution is another factor that prevents the optimal operation of the grid and the connected loads. Harmonics are attributable to proliferation of the diode-rectifier- or thyristor-rectifier-interfaced loads such as variable speed ac drives and power supplies in server farms, electric arc furnaces, and other non-linear loads, which are widely employed by the industrial sector. With wider adoption of harmonic-rich loads by the consumer sector as well, such as HDTVs and compact fluorescent lamps (CFLs), greater level of triplen harmonics associated with single-phase loads are also increasingly seen on the distribution grid. The increasing penetration of renewable resources and electrification of light-duty vehicles are expected to further aggravate the stresses and congestion on the utility grid.
Reactive power compensation is necessary for supporting the AC grid and maintaining a healthy voltage stability margin. Compensation can also enhance the utilization of system capacity, lower system losses, provide fault ride-through, and enable a quick fault recovery. Existing VAR and harmonic compensation technologies are either too expensive or inadequate to meet the dynamic needs of the modern and the future power system.
This dissertation presents a novel class of Dynamic VAR and Harmonic Compensators (DVHCs) for supplying or absorbing reactive power and providing harmonic filtering, where the compensation is in shunt with the line and the load. The underlying concept is based on augmenting a static or passive component like a capacitor or an inductor with a direct AC converter and imbuing the passive component with dynamic properties. The direct AC converter can be configured as a buck, a boost, or a buck-boost. A `fail-normal' switch is an integral part of the DVHCs that bypasses the converter when it fails, preserving the original functionality and the reliability of the passive component. The DVHCs are modular and scalable such that they can be employed in applications ranging from residential and industrial with voltages less than 480 V, to power distribution level with voltages as high as 35 kV. The Dynamic Inductor (D-IND) and the Dynamic Capacitor (D-CAP) are subclasses of the DVHCs. As the applications for supplying leading VARs are more prevalent, the primary focus of this work is on the buck, the boost, and the buck-boost configurations of the D-CAP.
To understand the characteristics and operation of the DVHCs, this work has developed time-domain models for analyzing the transient and dynamic behavior; frequency-domain models for understanding the harmonic interactions and the steady-state relationships between switch duty and current harmonics; and small-signal models for studying the dynamics of the converter due to various perturbations. The small-signal models also enable extraction of transfer functions in designing controllers and assessing stability margins.
Control architectures and techniques are presented for effectively controlling the D-CAP when commutating the semiconductor devices with both high and low switching frequencies.
In modularly scaling the DVHCs to higher voltages, three medium-voltage topologies are discussed. They are based on series-connecting fractionally-rated devices, AC flying capacitors, and series cascading multiple two-level cells. These implementations allow direct connect to the medium-voltage grid, thereby obviating the use of transformers, and subsequently reducing the losses, cost, complexity, and footprint. A novel AC snubber concept is proposed to provide safe commutation of the AC switches, fault tolerance by managing the energy trapped in parasitics and filters, and to enable dynamic and static voltage sharing when integrated around the series-connected devices.
Design equations for selecting and rating the devices and components in the buck, the boost, and the buck-boost configurations of the D-CAP are presented. Three sets of example designs, with one at low-voltage and two at medium-voltage, are discussed to demonstrate the typical size and ratings of the various components under realistic operating conditions.
Measurements and the related discussions of a 40 kVA buck D-CAP prototype built to validate the effectiveness of the proposed concepts are presented.
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Vetiška, Vojtěch. "Využití MERS obvodu v silnoproudé elektrotechnice." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219033.
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This graduation thesis is aimed in usage of MERS circuits in high-current electroengineering. The MERS circuit is a serial variable capacitor which capacity is possible to change by the help of switching of semiconductor components. On beginning of the thesis I shall acquaint you with usage of the MERS circuit. It will be sketched out their basic circuitry, the operating method, possibilities of transistors switching and calculation of the capacity capacitors for particular controlling method. On the prepared device we shall accomplish the predefined measurement. Furthermore we shall create the simulation by means of the Matlab programme. In the end we shall compare the results of the simulation with measured values.
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Shikoana, Victor. "Reactive power compensation, system and voltage stability of an industrial network with short circuit limiting coupler." Master's thesis, University of Cape Town, 1998. http://hdl.handle.net/11427/21324.
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This thesis investigates Sasol Three (Secunda) system's needs for reactive power compensation under voltage and transient stability conditions. A short circuit limiting coupler is designed and the transient and voltage stability studies are performed with a short circuit limiting coupler (SLC) applied at the two 132 kV incoming supply lines from Eskom. The simulations are based 011 solving ordinary loadflow cases augmented with dynamic models of the system elements. Motor loads were modelled in detail incorporating their dynamic characteristics. 75% of the Sasol Three system load constitute induction motors and 25 % is constant impedance and constant current load models. Power System Simulator (PSS/E) package was utilized in carrying out these studies. The most impressive results is the way the Sasol Three System recovers in the range of milliseconds when subjected to severe disturbance with regard to voltage and transient stability. With a short circuit limiting coupler included at the two incoming supply lines, the system still recovers after being subjected to a disturbance. In this project it is shown that there is no need to install reactive power compensation system on the Sasol Three System. This is because of the capabilities of the present system in regulating reactive power through the network during abnormal system conditions. It is also shown in this thesis that the Sasol Three network is transient and voltage stable when a short circuit limiting reactor is applied at the incoming lines from Eskom. The extent to which the-network is transiently stable is also determined.
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Cetin, Alper. "Design And Implementation Of A Voltage Source Converter Based Statcom For Reactive Power Compensation And Harmonic Filtering." Phd thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608307/index.pdf.
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In this thesis, design and implementation of a distribution-type, voltage source converter (VSC) based static synchronous compensator (D-STATCOM) having the
simplest converter and coupling transformer topologies have been carried out. The VSC STATCOM is composed of a +/- 750 kVAr full-bridge VSC employing selective harmonic elimination technique, a low-pass input filter, and a &<br>#8710<br>/Y
connected coupling transformer for connection to medium voltage bus. The power stage of VSC based STATCOM is composed of water-cooled high voltage IGBT modules switched at 850 Hz for the elimination of 5th, 7th, 11th, 13th, 17th, 19th, 23rd,and 25th voltage harmonics. Special care has been taken in the laminated busbar design to minimize stray inductances between power semiconductors and dc link
capacitor. Reactive power control is achieved by applying the phase angle control technique. The effect of input filter on total demand distortion has been investigated theoretically by mathematical derivations.
The proposed VSC STATCOM has been implemented for reactive power compensation of Coal Preparation System in Kemerkö<br>y Thermal Power Plant. The field test results have shown the success of the implemented system in view of fast
response in reactive power compensation, and minimum input current harmonic content, and compliance with the IEEE Std. 519-1992 even for the weakest power systems. The application of selective harmonic elimination technique and phase angle control to VSC STATCOM has led to optimum switching frequency and device utilization for high voltage IGBTs at the expense of slower response as compared to other PWM techniques.
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Twining, Erika. "Voltage compensation in weak distribution networks using shunt connected voltage source converters." Monash University, Dept. of Electrical and Computer Systems Engineering, 2004. http://arrow.monash.edu.au/hdl/1959.1/9701.
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Quillen, Chris A. "Analysis of reactive power compensation methods in distribution systems a thesis presented to the faculty of the Graduate School, Tennessee Technological University /." Click to access online, 2009. http://proquest.umi.com/pqdweb?index=2&did=1913184261&SrchMode=1&sid=2&Fmt=6&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1264100685&clientId=28564.
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Deniz, Mustafa. "Investigation Of Multilevel Inverters For D-statcom Applications." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/3/12611447/index.pdf.
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The most important advantages of Multilevel Inverters are the absence of a coupling transformer for medium voltage applications and low harmonic current content. In this way, relocatable and economical STATCOM systems can be realized. Complex control algorithms and the isolation problems of measurement devices and power supplies are the main challenging parts of this type of application. In this study, the design, realization, and the performance of a Voltage Source Type Cascaded Multilevel Converter Based STATCOM will be investigated in terms of digital computation, control hardware and the semiconductors devices commercially available in the market. This research work is fully supported by the Public Research Grant Committee (KAMAG) of TUBiTAK within the scope of National Power Quality Project of Turkey with the project No: 105G129.
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Fan, Zaiming. "Investigation on smart bi-directional inverter with quantitative reactive power compensation and interleaved DC/DC converter for micro-grid system." Thesis, University of Cumbria, 2016. http://insight.cumbria.ac.uk/id/eprint/3326/.
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The PhD project aims to develop a smart grid-connected inverter (SGCI) for a micro-grid, which can be applied in a built environment such as a community, and associated power electronic DC/DC converters. The micro-grid generally includes distributed renewable power generators and battery storage. The SGCI is a bi-directional DC/AC inverter for distributed generation with battery storage installed at its DC side. In one aspect, it is expected the DC/AC inverter functions as a controlled inverter that can deliver expected real power to the power grid with quantitative reactive power compensation (RPC). In other words, all the SGCIs in the community microgrid can share the reactive power of the whole community because a SGCI can quantify its active and reactive power output. It is also expected that the inverter can work in both on-grid and off-grid modes. In other words, the DC/AC inverter functions as a controlled rectifier with high quality power factor correction (PFC), which can deliver expected DC power from the AC power grid at unity power factor. With the above features, battery storage on the DC bus of the SGCI can be charged/discharged through a four-phase, interleaved, bi-directional, boost/buck DC/DC converter (IBDBBC) for distributed renewable power system, either wind or solar PV or hybrid wind/solar PV system. The IBDBBC can discharge power from a low voltage battery to a high voltage DC bus as the IBDBBC operates in boost mode, or it can also draw power from the DC bus to charge the battery as the IBDBBC operates in buck mode. Based on MATLAB/Simulink, a mathematical model was developed for the grid-connected bi-directional DC/AC inverter that operates as a rectifier with PFC and as a grid-connected inverter (GCI) with expected real power output and quantitative RPC. In a practical application, the sampling of input signal through AD converter usually has some noise due to common-mode interference; simulation results demonstrate that the second order generalised integrator (SOGI) has great advantages to prevent interference. Therefore, SOGI can be utilised to construct a pair of orthogonal signals in a single-phase system to instantaneously split grid’s active and reactive power to achieve RPC for local community loads. The methodology of the constructed the pair of orthogonal signals was also used to generate the required reference current for the DC/AC inverter when which operated as a single-phase rectifier with PFC. Using three TI C2000 Solar Inverter DSK Boards, a small lab scale distributed power system was developed. In the lab distributed power system, the operating mode of the inverters could be switched between on-grid and off-grid through instruction from the control centre. The lab test outcomes demonstrate that each distributed power system unit worked properly under loss of power grid signal, simulating grid failure.
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Dike, Damian Obioma. "Index-based reactive power compensation scheme for voltage regulation a dissertation presented to the faculty of the Graduate School, Tennessee Technological University /." Click to access online, 2009. http://proquest.umi.com/pqdweb?index=76&did=1919277961&SrchMode=1&sid=1&Fmt=6&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1265041751&clientId=28564.
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Raimondo, Giuliano. "Power quality improvements in 25kV 50 Hz railway substation based on chopper controlled impedances." Thesis, Toulouse, INPT, 2012. http://www.theses.fr/2012INPT0004/document.
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Ce travail est le résultat d'une collaboration entre le laboratoire LAPLACE, la "Seconda Università degli Studi di Napoli" (SUN) et la Société National des Chemins de fer Français SNCF. Le sujet de recherche concerne l'utilisation de dispositifs électroniques de puissance dans les sous stations ferroviaires 25kV/50Hz afin d’améliorer la qualité de l'énergie électrique. Dans le transport ferroviaire, le système d'électrification monophasé 25kV/50Hz est largement diffusé en particulier pour les lignes ferroviaires à grande vitesse. Bien qu'aujourd'hui les systèmes d’alimentation en courant continu soient encore largement utilisés, l'adoption du courant alternatif monophasé offre des avantages économiques pour les infrastructures d'environ 30% en termes d'investissement, d'exploitation et d'entretien. Initialement, compte tenu de la simplicité du circuit, il n'y avait aucune nécessité d'intégrer de l'électronique de puissance dans les sous stations. Toutefois, au cours de la décennie passée, l'intérêt pour ces équipements est apparu car ils peuvent apporter une solution d'optimisation du réseau lorsque le trafic augmente ou lorsqu’une nouvelle sous station est envisagée. Deux principaux types de dispositifs sont installés aujourd'hui sur le réseau ferré français : les compensateurs de puissance réactive et les compensateurs de déséquilibre de tension. Cette thèse présente de nouvelles topologies de compensateurs basées sur le concept d’impédances contrôlées par gradateur MLI. Comparées aux solutions existantes, ces topologies ont des caractéristiques particulièrement intéressantes en termes de pertes dans les semi-conducteurs et de volume des composants réactifs. Le manuscrit contient trois parties principales: La première partie présente le principe de l’électrification en 25kV/50Hz et souligne l’intérêt d’installer des moyens de compensation statique dans les sous stations. Après une description des solutions actuellement utilisées, le concept d’impédance contrôlée par gradateur MLI (CCI : Chopper Controlled Impedance ) est ensuite présenté. La deuxième partie du travail concerne l'utilisation du concept de CCI pour la compensation de puissance réactive. La sous-station SNCF de Revest est considérée comme cas d’étude. Celle-ci est équipée d'un transformateur monophasé de 60MVA dont le primaire est connecté à une ligne de transport 225kV. Deux topologies de compensateur de puissance réactive, basées sur des montages abaisseur ou élévateur de tension sont présentées. Le dimensionnement des gradateurs est effectué sur la base d'une campagne de mesures réalisée à la sous station. Des simulations numériques utilisant des formes d’ondes réelles de courant et de tension sont présentées. Des résultats expérimentaux effectués à la plateforme de test de la SNCF sur un prototype de 1,2MVAR permettent de valider le concept de CCI. La dernière partie du travail concerne le problème du déséquilibre de tension en amont de la sous station. Un circuit de Steinmetz « actif », toujours basée sur des gradateurs MLI, est présenté et étudié. La sous station SNCF d'Evron est alors considérée comme cas étude. Celle-ci comporte un transformateur de 32MVA et est connectée à une ligne de transmission 90kV. Les mesures effectuées sur le site permettent le dimensionnement du compensateur ainsi que l’utilisation des formes d'onde réelles de courant et de tension dans les simulations numériques. Une comparaison avec des solutions classiques basées sur des onduleurs 2 niveaux et 3 niveaux souligne les avantages de la solution proposée. Ainsi, les résultats des calculs et des simulations montrent que l'énergie stockée dans les éléments réactifs est réduite d’un facteur six et que les pertes dans les semi-conducteurs sont réduites de 40%. Des résultats expérimentaux obtenus sur une maquette de 1.5 kVA permettent de valider le principe du circuit de Steinmetz actif<br>This work is the result of collaboration between the LAPLACE laboratory, the “Seconda Università degli Studi di Napoli” (SUN) and the French national railways operator SNCF. The research topic treated herein concerns the use of power electronic devices in 25kV/50Hz railways substations to achieve power quality improvements. In railway transportation, single-phase 25kV-50Hz electrification system is widely diffused especially for high-speed railway applications. Although electrified DC systems are still widely applied, the adoption of AC single-phase system offers economical advantages for the infrastructures of about 30% in terms of investment, exploitation and maintenance. In early ages, due to its very simple diagram, there was no necessity to integrate power electronics in substations. However, for the last decade, the interest in power electronic equipments raised since they can provide the solution for network optimization when traffic increases or when a difficulty is foreseen for a substation implementation. Two types of devices are implemented today on the French Railway Network: Reactive Power compensators and Voltage Unbalance compensators. This thesis presents an investigation into new topologies based on the concept of “Chopper Controlled Impedances”(CCI). Compared to existing solutions, the new topologies show interesting features in terms of semi-conductor losses reduction and volume of reactive components. The manuscript is developed through three main parts: Firstly, the French railways system is introduced and the interest in installing power electronic compensators in substations is highlighted. After a brief description of currently used solutions, the CCI concept is presented: the use of Pulse Width Modulated AC Choppers allows achieving structures which behave as variable impedances. In the second part, the use of CCI structures in reactive power compensation is investigated. The SNCF substation of Revest is under study. It is equipped by a 60MVA single phase transformer with the primary side connected to a 225kV transmission line. Based on the step-down or step-up functioning mode of CCIs, two topologies of reactive power compensator are presented. The converter design is developed on the base of a measurement campaign carried out at the substation. Numerical simulations using real current and voltage waveforms are presented. Finally, experimental results carried out at the SNCF test platform on a 1.2MVAR prototype are shown. In the last part, the problem of voltage unbalance is treated. Using the concept of CCI, the feasibility of an active Steinmetz circuit based on AC choppers is explored. As a case study, the substation of Evron is considered. It is a 32MVA substation connected to a 90kV transmission line. Measurements carried out on the substation site allow the compensator design and the possibility to consider real waveforms for current and voltage in numerical simulations. A comparison with classical solution based on two levels VSI and three levels NPC-VSI highlights the advantages of the proposed solution. Calculation and simulation results show that the stored energy in reactive elements is reduced by a factor six whereas the semiconductor losses are 40% lower. Experimental results obtained on a scaled demonstrator (1.5 kVA) validate the principle of the active Steinmetz circuit
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Jurák, Viktor. "Kompenzace přetoků jalového výkonu do VN soustavy." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2019. http://www.nusl.cz/ntk/nusl-400568.
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This master thesis is focused on analysis of reactive power flow in LV and MV networks. In the first part there is a definition of reactive power and description of individual parts of electrical networks that contribute with their reactive power to distribution network. The second part is dedicated to calculation of power flow in simulation software PSS® Sincal where on numerical models of network different types of network configuration are tested and consequently its influence on reactive power flow is evaluated. A more detailed analysis is dedicated to reactive power compensation in networks with distributed generation equipped with Volt-Var regulation and its possible negative mutual influence. This thesis also includes general recommendation on the basis of network simulation analysis concerning installation of compensating systems in distribution transformer station.
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Lowinsky, Luc Anthony. "Nouvelle topologie de Compensateur de Puissance Réactive pour les Réseaux Ferrés 25 kV / 50 Hz." Thesis, Toulouse, INPT, 2010. http://www.theses.fr/2010INPT0036/document.
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Le travail présenté dans ce mémoire s’est déroulé dans le cadre d’une collaboration entre le groupe Convertisseur Statique du laboratoire LAPLACE et le département " Installations Fixes de Traction Electrique " de la Direction de l’Ingénierie de la SNCF. Aujourd'hui, la majorité du trafic sur le réseau ferré monophasé 25 kV / 50 Hz est assurée par des locomotives équipées de redresseurs contrôlés à thyristors. Du fait de l'augmentation du trafic, l'utilisation de ces locomotives nécessite la mise en place de moyen de compensation de puissance réactive afin de maintenir la tension caténaire à un niveau acceptable et de réduire la facture en énergie réactive. La correction du facteur de déplacement est réalisée en partie par des batteries de compensation fixes dont lapuissance est limitée par la tension maximale admissible à vide sur la caténaire. Afin d’adapter le niveau de compensation à la consommation, la partie fixe est complétée par un dispositif réglable basé sur une réactance contrôlée par des thyristors. Bien qu’il soit simple dans son principe, ce dispositif nécessite un filtrage des harmoniques en basse fréquence avec des circuits LC volumineux. L’objectif de cette thèse est de proposer une nouvelle topologie de compensateur de puissance réactive à haut rendement et utilisant un contrôle à modulation de largeur d’impulsion dans le but de minimiser le volume des éléments de filtrage. La première partie de ce mémoire est consacrée à une étude comparative de différentes topologies du point de vue des pertes dans les semi-conducteurs et du dimensionnement des éléments de filtrage associés. Les résultats de cette étude montrent que les topologies à base de gradateurs MLI, constituent les solutions les plus intéressantes pour réaliser le compensateur. La deuxième partie du travail concerne l’étude de l’insertion d’un compensateur à base de gradateurs MLI sur le réseau ferré avec la prise en compte des interactions harmoniques. Le cas d’étude concerne une sous-station où doit être implantée une compensation variable de 3 MVAR. Un relevé des courants délivrés par la sous-station a été effectué dans le but d’analyser leur contenu harmonique. Une modélisation de la sous-station et du compensateur est ensuite proposée et des simulations temporelles de l’ensemble sont réalisées en prenant en compte les formes d’ondes réelles des courants absorbés par les trains. Finalement, cette étude par simulation permet d’affiner le dimensionnement du compensateur à gradateurs MLI et des éléments de filtrage associés. Elle met en évidence l’avantage d’une solution, avec des gradateurs MLI en montage élévateur de tension, qui fonctionne sans transformateur et réutilise les batteries de compensation fixes déjà installées en sous-station à la fois comme diviseur de tension et éléments de filtrage. Afin de valider le principe de cette nouvelle topologie de compensateur statique de puissance réactive, un démonstrateur de 1,2 MVAR est mis en oeuvre et testé sur une plateforme d'essai de la SNCF<br>The work presented in this thesis is the result of collaboration between the Static Converters research group of LAPLACE Laboratory and the department "Installations Fixes de Traction Electrique" of the Engineering Division of the French Railways company, SNCF. Nowadays, most of the traffic in 25 kV – 50 Hz lines is achieved by old locomotives equipped with thyristor rectifiers. As traffic and load increase, reactive power compensation devices are required to keep the overhead line voltage at acceptable level and to reduce the spending for reactive power. The basic power factor correction is completed by fixed compensation banks. But the difficulty of such configuration is the no-load operation of overhead lines. The voltage can increase out of the 29 kV standard limit and to avoid this problem, variable reactive power compensator is often added to the fixed compensation banks. Nowadays, SNCF is equipped with thyristor based static VAR compensators (SVC). The main drawback of this topology is the requirement of a large LC shunt filter tuned for the third harmonic. The goal of this thesis is to find a new high-efficiency topology of STATic COMpensator (STATCOM) using PWM control to minimize the filtering components. The first part of this thesis focuses on a comparative study of different topologies in terms of semiconductor losses and filter elements size. The results of this study show that the topologies based on PWM AC Chopper are the most interesting solutions to achieve the compensator. The second part of the work concerns the influence of the connection of a STATCOM to a substation and focuses on the harmonic interactions with locomotives. The study case concerns a high traffic substation where a 3 MVAR STATCOM should be installed. Substation output current measurement was carried out in order to analyze its harmonic content. Models of the substation and the STATCOM are then proposed and simulations using real current waveforms are performed. Finally, this simulation study helps to refine the features of the AC Chopper topology and its filter elements. It highlights the advantage of a solution, with boost AC Choppers which operate without transformer and reuse the fixed compensation banks already installed in the substation as voltage divider and filter. To validate the principle of this new topology of STATCOM, a 1.2 MVAR prototype is built in LAPLACE laboratory and tested on a SNCF test platform
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Lebedka, Serhii Mykolaiovych, Сергей Николаевич Лебедка, Сергій Миколайович Лебедка та Д. А. Сай. "Современные устройства компенсации реактивной мощности". Thesis, Изд-во СумДУ, 2008. http://essuir.sumdu.edu.ua/handle/123456789/4161.
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Horenský, Martin. "Dynamická kompenzace." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-220932.
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This master’s thesis is focusing on compensation of reactive power, especially on creating demonstrative model of static var compensation unit (SVC). Main topic of thesis is to apply this device for fast balancing dynamic conversions of recieved reactive power. In theoretical part is described suitable method for determination of instantaneous power. Next, there is basic description of all means used for compensation of reactive power and detailed description of the SVC compensator. Practical part includes design of compensation unit and control program in LabVIEW. The pq theory is implemented for detection instantaneous power. The results of validating functionality of compensator are presented in the last part of thesis.
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Гейруш, Гергей Гаврилович, та Herhei Heirush. "Забезпечення ефективності системи електропостачання виробництва покрівельного прокату в ТОВ «Євро-прокат»". Master's thesis, Тернопільський національний технічний університет імені Івана Пулюя, кафедра електричної інженерії,Тернопіль, Україна, 2021. http://elartu.tntu.edu.ua/handle/lib/36670.
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Системи електропостачання - це сукупність джерел електричної енергії, силових трансформаторів, повітряних та кабельних ліній електропередачі, розподільних пристроїв, перетворювачів струму та напруги, засобів захисту та управління, допоміжних пристроїв та інших технічних засобів, призначена для забезпечення споживачів електроенергією у необхідній кількості необхідної якості.
Якість електроенергії - це сукупність властивостей електричної енергії, що відображає ступінь відповідності встановленим значенням параметрів електричної енергії, кількісно характеризує властивості електричної енергії (частоту, напругу, форму кривої напруги), є мірою електромагнітного впливу системи електропостачання на прилади, апарати, засоби управління, зв’язку та ін., проявляється у вигляді кондуктивних електромагнітних завад. Зниження якості електроенергії у системах електропостачання може призвести до зміни режимів роботи електроприймачів і в результаті – до скорочення терміну служби електрообладнання, підвищення ймовірностей аварій тощо. В реальних системах електропостачання підтримання якості електроенергії в заданих межах забезпечується автоматичним регулюванням окремих показників якості [5].
Нині з’явилися нові технології, які суттєво впливають на забезпечення надійності електроенергетичної системи. Насамперед слід зазначити: нове покоління комутаційної апаратури для всіх класів напруги з практично необмеженим ресурсом та електронні КРП, що дозволяє переглянути завдання надійності підстанцій; стрімкий розвиток силової електроніки та нових матеріалів; значний прогрес у галузі ізоляції електрообладнання [23].
Системи електропостачання промислових підприємств не повинні бути багатоступінчастими, мережі живлення не повинні бути довгими, а спосіб прокладання мережі повинен бути максимально простим. Крім того, система зобов’язана забезпечувати можливість впровадження нового обладнання, тобто повинна бути масштабованою<br>У кваліфікаційній роботі розроблена модернізація ефективної системи електропостачання підприємства з технологією виробництва покрівельного прокату. Проаналізований технологічний процес порошкового фарбування листового металопрокату. Розраховані електричні навантаження силової та освітлювальної мереж, струми короткого замикання; проведений вибір ефективних перерізів кабельно–провідникової продукції. Проведений розрахунок ефективного схемо–технічного рішення електромережі підприємства з дворівневим розміщенням установок компенсації реактивної потужності.<br>In the qualification work the modernization of the efficient power supply system of the enterprise with the technology of roofing production is developed. The technological process of powder coating of rolled sheet metal is analyzed. Electrical loads of power and lighting networks, short-circuit currents; the choice of effective cross-sections of cable-conductor products is calculated. The calculation of the effective circuit-technical solution of the power grid of the enterprise with two-level placement of reactive power compensation units is carried out.<br>ВСТУП ...
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1 АНАЛІТИЧНИЙ РОЗДІЛ ...
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1.1 Аналіз енергетичної ефективності систем електропостачання ....
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1.2 Аналіз методів дослідження ефективності систем електропостачання промислових підприємств ...
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1.3 Аналіз технологічного процесу порошкового фарбування листового металопрокату ...
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1.4 Автоматичний пристрій регенерації порошкової фарби ...
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1.5 Аналіз енергетичних переваг застосування полімерних порошкових покриттів ...
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1.6 Загальна характеристика електроприймачів ...
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1.7 Загальна характеристика електроспоживання підприємства ...
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1.8 Вибір схеми електропостачання ...
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1.9 Висновки до розділу ...
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2 РОЗРАХУНКОВО–ДОСЛІДНИЦЬКИЙ РОЗДІЛ ...
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2.1 Загальна характеристика потужностей основного виробництва.. .
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2.2 Розрахунок електричних навантажень основного виробництва ...
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2.3 Розрахунок центрів електричних навантажень ...
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2.4 Визначення розрахункових навантажень виробничого обладнання ...
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2.5 Розрахунок електричного освітлення виробничих дільниць ...
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2.6 Розрахунок навантаження щитка освітлення ...
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2.7 Розрахунок потужності розподільчих пристроїв ...
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2.8 Розрахунок навантаження силового трансформатора ...
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2.9 Схемо-технічні рішення ефективних електромереж промислових підприємств ...
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2.10 Висновки до розділу ...
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3 ПРОЕКТНО-КОНСТРУКТОРСЬКИЙ РОЗДІЛ ...
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3.1 Вибір захисної апаратури електромережі підприємства ...
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3.2 Проєктне рішення ...
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3.3 Розрахунок максимальних струмів кіл навантаження силового трансформатора ...
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3.4 Вибір компенсувальних пристроїв реактивної потужності ...
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3.5 Вибір площі перерізу проводів і жил кабелів ...
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3.6 Кабельний журнал ...
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3.7 Перевірка струмовідних частин на термічну стійкість ...
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3.8 Релейний захист трансформаторів підстанції ...
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3.9 Висновки до розділу ...
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4 ОХОРОНА ПРАЦІ ТА БЕЗПЕКА В НАДЗВИЧАЙНИХ
СИТУАЦІЯХ ...
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4.1 Аналіз і заходи з усунення шкідливих факторів виробництва фарбованого покрівельного прокату ...
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4.2 Електробезпека на виробництві. Технічні засоби
електробезпеки ...
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4.3 Стійкість виробництва фарбованого металопрокату в умовах дії надзвичайних ситуацій ...
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4.4 Вимоги щодо улаштування системи електрозабезпечення виробництва у надзвичайних ситуаціях ...
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ЗАГАЛЬНІ ВИСНОВКИ ...
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ПЕРЕЛІК ПОСИЛАНЬ ...
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Kapidou, Alexandra. "Application for Wind Farm Integration Complying with the Grid Code by Designing an Outer Control Strategy for the Converter." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-187686.
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The continuously increasing energy penetration from wind farms into the grid raises concerns regarding power quality and the stable operation of the power system. The Grid Code´s requirements give strict guidelines for a wind farm´s behaviour under faulty or abnormal operating conditions.The primary purpose of this project is the application of a STATCOM for wind farm integration complying with the Grid Code. Towards that, an outer control strategy for the converter is designed so as to regulate the voltage at the point of common coupling by providing reactive power compensation. Thus the safe operation of the grid will be ensured since the wind farm will follow the Grid Code´s standards.The existing Grid Code requires only a positive sequence current controller. This study attempts to investigate whether this is sufficient or not and to examine the possibility of extending the Grid Code requirements so as to incorporate a negative sequence current controller as well. The results support the latter suggestion. Also, the use of SiC devices was also considered in this project.<br>Den ständigt ökande penetrationen av vindenergi i elnätet väcker farhågor om elkvalitet och stabil drift av kraftsystemet. Nätkoden (Grid Code) ger strikta riktlinjer för en vindkraftsparks beteende i felfall och under onormala driftsförhållanden.Huvudsyftet med detta projekt är att använda en STATCOM för integration av vindkraftsparker så att nätkoden uppfylls. I detta projekt utformas en yttre reglerstrategi för omriktaren för att reglera spänningen vid anslutningspunkten för vindkraftsparken genom att tillhandahålla reaktiv effektkompensering. Därigenom uppnås en säker drift av nätet eftersom vindkraftparken kommer att följa nätkoden.Den befintliga nätkoden kräver endast styrning av plusföljdskomponenten av strömmen. Denna studie försöker undersöka om detta är tillräckligt samt undersöka möjligheten för att utvidga nätkoden genom att införa ett krav på styrning av negativ-sekvens ström. Resultaten stöder det sistnämnda förslaget. Även användningen av halvledarkomponenter av kiselkarbid-SiC studerades i detta projekt.
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Paul, Sushanta. "Optimal capacitor placement for line-loss reduction and importance of voltage reduction during reactive power compensation and its effects on load, line loss, and generation." Diss., Wichita State University, 2013. http://hdl.handle.net/10057/10615.
Full textAbstract:
A methodology to determine the optimal capacitor locations and sizes to minimize line loss on a radial distribution system was developed in this work. Both the power loss index (PLI)-based approach and the loss sensitivity coefficient-based approach were comparatively studied to determine the optimal capacitor location. The index-based approach combined with a genetic algorithm was used to determine the capacitor sizes. After reactive power compensation voltage-dependent loads consume more power because of the increase in node voltage; therefore, customers pay more for their electricity while utilities experience savings from line-loss reduction. Therefore, a rationale for the necessity of reducing voltage for load demand reduction during reactive power compensation is presented, and the optimal voltage setting at the substation regulator is determined. The joint effect of ambient temperature, price, size, and phase kVAr of the capacitor on load, line loss, and generation is analyzed using a 24 factorial design. How consumer energy consumption, line loss, and generation are affected by voltage reduction is also evaluated. Since bus voltage also depends on line resistance, which varies with ambient temperature, the impact of temperature on power consumption, line loss, and generation is discussed as well. At reduced voltage, variations in line loss need to be analyzed, because losses affect the cost-benefit analysis. A model is derived that explains, at reduced voltage, how line loss varies with the type of load. Also analyzed is the effect of line resistance on line loss for various types of loads. The results of this work will improve the effectiveness and reliability of future voltage-reduction programs. Finally, analyses for negative line loss, higher voltage at the downstream node, and the active and reactive current components of a capacitor are presented in this work.<br>Thesis (Ph.D.)--Wichita State University, College of Engineering, Dept. of Electrical Engineering and Computer Science
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Omar, Moien. "Power Converters and Control for Grid Connected Microgrids under Unbalanced Operating Conditions." Doctoral thesis, Università di Catania, 2015. http://hdl.handle.net/10761/3728.
Full textAbstract:
Nowadays, Renewable Energy Sources (RESs) have become more attractive and affordable due to recent advances in power electronic devices and control systems. Micro-Grids (MGs) represent a new paradigm of electrical grids with Distributed Generation (DG) units: they are generally composed of power converters, RESs, Energy Storage Systems (ESSs), local loads with measurement and control systems.
MGs have the potential to operate in both, grid connected and islanded mode. During islanded mode, ESSs are essential for MGs to enable grid forming control. On the other hand, during grid connected mode, the ESSs allow the MGs to provide different services to the main grid. For example, grid power supporting during peak periods; however, in case of unbalanced operational conditions for MGs, due to single phase loads and single phase generation units, the power exchange between MGs and the main grid will add negative effects to the main grid.
Since the MG is supposed to be grid friendly when connected to the external grid, the unbalanced currents should preferably be handled within the MG. Therefore, the power converters of MGs have to provide the zero sequence and negative sequence currents.
The main objective of this thesis is to obtain grid friendly MGs, in order to improve the functionality of MGs during the grid connected mode, under unbalanced operating conditions.
Power converters with ESSs can be adopted to mitigate the negative effects of unbalanced grid connected MGs. However, suitable control strategies are required. In this thesis, a control strategy based on vector control and symmetrical components is proposed for three-phase four-legs power converter interfaces Energy Storage Batteries (ESBs) to obtain a Multi-Functional Power converter (MFPC), in order to resolve the problems of the unbalanced three phase currents, and to the reactive power compensation.
Several working conditions have been analyzed, and solutions for some common and frequent critical conditions, such as the imbalance of the power system due to single-phase loads and single phase DGs have been presented. Discussions of technical issues like output filter design and four legs VSIs modulation techniques, synchronization, power converters topologies and control have also been discussed.
The proposed control strategy of MFPC is able to mitigate the negative effects of grid connected MGs such as, unbalanced and reactive power compensation. This allows the MGs to become grid friendly , even it is working under highly unbalanced and poor power factor conditions, and also performs power management to optimize the MGs supporting services with smart grid functionality.
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Genc, Murat. "Design And Digital Implementation Of Thyristor Controlled Reactor Control." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/3/12609184/index.pdf.
Full textAbstract:
In this research work, the control system of 16 MVAr, 13.8 kV TCR will be
designed and digitally implemented. A Real-Time Control System (NI
CompactRIOTM Reconfigurable I/O) and a Digital Platform (NI LabVIEWTM Gcode)
are used in the digital implementation of TCR control system. The digital
control system is composed of reactive power calculation, firing angle
determination and triggering pulse generation blocks. The performance of control
system will be tested in the field. The simulation results will also be compared
with test data.
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Харевич, Віктор Ігорович, та Viktor Harevych. "Використання нерегульованих конденсаторних батарей в мережах 10 кВ". Master's thesis, Тернопільський національний технічний університет імені Івана Пулюя, кафедра електричної інженерії,Тернопіль, Україна, 2021. http://elartu.tntu.edu.ua/handle/lib/36658.
Full textAbstract:
Розвиток сучасної енергетики ґрунтується на поліпшенні технічних і економічних параметрів силового обладнання, підвищення їх надійності, рівня автоматизації та пропускної спроможності лінії електропередачі при постійному підвищенні якості електричної енергії і, відповідно, зменшенням втрат. Одним із найважливіших на сьогоднішній день питань при зростанні споживаної потужності залишається проблема зниження втрат та підвищення пропускної здатності, що в свою чергу вимагає розробки заходів щодо оптимізації параметрів режиму мережі з відповідним їх технічним і економічним обґрунтуванням.
Зазначені проблеми оптимізації роботи міських розподільчих мереж не є чимось новим – вони розглядається вже на протязі довгого часу [1]. Зазвичай поставлені задачі оптимізації параметрів і режимів роботи потрібно вирішувати ще на стадії проектування, розвитку або реконструкції таких електричних мереж. На даний час усі міські розподільні мережі виконані у вигляді замикаючої ланки в енергетичній системі, яка забезпечує споживачів потрібною електричною енергією [2].
Варто відмітити, що сучасні міські поселення на теперішній час харак-теризуються доволі високою густиною електричних навантажень з питомою часткою споживання електричної енергії на малій території, що обумовлює збільшення втрат електричної енергії. В результаті доволі значного застосу-вання електричних приймачів нового покоління, які споживають з мережі також і значну частку реактивної потужності поряд з активною потужністю, мають місце значні втрати електричної енергії в електромережах 10/0,4 кВ.<br>У даній кваліфікаційній роботі було розглянуто проблеми зниження втрат електричної енергії в міських електричних мережах, виконано оптимізаційний розрахунок розміщення нерегульованих батарей статичних конденсаторів на шинах трансформаторних пунктів напругою 10/0,4 кВ та розрахунок наванта¬жу¬вальних втрат типової схеми без компенсації реактивної потужності і з вста-новленням нерегульованих батарей на шинах ТП 10 кВ і 0,4 кВ. Отримані розрахунки за допомогою типової схеми розміщення нерегу¬льо¬ваних конденсаторних батерей на шинах трансформаторних пунктів 10 кВ і 0,4 кВ розподільчої електромережі показали, що максимальне зниження річних втрат можна отримати при їх встановленні на шинах ТП 0,4 кВ, що дозволяє отримати кращий ефект від компенсації реактивної потужності у розподільній мережі та значно знизити втрати електричної енергії і, відповідно, відтермі¬нувати будівництво нових силових потужностей, що є надзвичайно актуаль¬ною проблемою на сьогоднішній день<br>In this qualification work the problems of reduction of electric energy losses in city electric networks were considered, optimization calculation of placement of unregulated batteries of static capacitors on busbars of transformer points with voltage 10 / 0,4 kV and calculation of loading losses of the standard scheme without compensation of reactive power and with installation of unregulated batteries on 10 kV and 0.4 kV busbars. The calculations obtained using a typical scheme of placement of unregulated capacitor banks on the busbars of transformer points 10 kV and 0.4 kV of the distribution network showed that the maximum reduction of annual losses can be obtained by installing them on busbars 0.4 kV, which allows to obtain better effect of reactive power compensation in the distribution network and significantly reduce electricity losses and, accordingly, delay the construction of new power plants, which is an extremely important issue today<br>ЗМІСТ
ВСТУП
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1 АНАЛІТИЧНИЙ РОЗДІЛ
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1.1 Аналіз втрат електроенергії в розподільних мережах 10/0,4 кВ
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1.2 Аналіз режимів роботи в розподільних мережах 10/0,4 кВ
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1.3 Заходи щодо зниження втрат в мережах 10/0,4 кВ
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1.4 Способи компенсації реактивної потужності в мережах 10/0,4 кВ
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1.5 Проблеми компенсації реактивної потужності в міських мережах
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1.6 Висновки до розділу 1
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2 ПРОЕКТНО-КОНСТРУКТОРСЬКИЙ РОЗДІЛ
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2.1 Визначення вхідних даних
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2.2 Вибір потужності конденсаторних батарей
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2.3 Вибір місця встановлення конденсаторної батареї
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2.4 Висновки до розділу 2
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3 РОЗРАХУНКОВО-ДОСЛІДНИЦЬКИЙ РОЗДІЛ
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3.1 Визначення вихідних даних для проведення розрахунку
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3.2 Розрахунок втрат потужності у нормальному режимі
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3.3 Вибір нерегульованих батарей статичних конденсаторів
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3.4 Втрати електроенергії на шинах ТП 0,4 кВ при встановленні НБСК
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3.5 Втрати електроенергії на шинах ТП 10 кВ при встановленні НБСК
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3.6 Використання нерегульованих конденсаторних батарей на шинах трансформаторних пунктів 0,4 кВ
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3.7 Висновки до розділу 3
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4 ОХОРОНА ПРАЦІ ТА БЕЗПЕКА В НАДЗВИЧАЙНИХ СИТУАЦІЯХ
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4.1 Заходи безпеки при експлуатації пристроїв компенсації реактивної потужності
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4.2 Захист персоналу у діючих електроустановках
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ЗАГАЛЬНІ ВИСНОВКИ
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ПЕРЕЛІК ПОСИЛАНЬ
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Lakkireddy, Jahnavi. "Steady State Voltage Stability Enhancement Using Shunt and Series FACTS Devices." ScholarWorks@UNO, 2014. http://scholarworks.uno.edu/td/1881.
Full textAbstract:
It is specifically important to focus on voltage stability analysis of the power system to avoid worst case scenarios such as voltage collapse. The purpose of this thesis is to identify methods for enhancing the steady-state voltage stability using FACTS devices and determining their impact on real and reactive power losses, improvement of bus voltage magnitude, and transmission line loadability. To achieve this, FACTS devices such as Static VAR Compensator (SVC), Static Synchronous Compensator (STATCOM), and Thyristor Controlled Series Capacitor (TCSC) are used in the test system as three separate test cases. The results obtained assist in drawing conclusions on the effectiveness of each FACTS devices at generator, load and swing buses, on lines between two load buses, and between a load bus and a generator bus, in terms of metrics such as voltage magnitude profile, PV curves, and active and reactive power losses.
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Stypulkowski, Yuri Solis. "Alocação ótima de compensação de potência reativa." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/165244.
Full textAbstract:
Este trabalho propõe uma metodologia para enumerar soluções, que indiquem a barra e a compensação de potência reativa necessária para o sistema elétrico sob análise, que atendam aos requisitos avaliados pela função objetivo e as restrições. Nessa alocação de compensação ótima de potência reativa, obtemos as melhores barras e configurações de potências e tecnologias de dispositivos de compensação, minimizando as perdas totais de potência ativa da rede. Em redes fracas com conversores de frequência (por exemplo, para conexão de fontes renováveis, ou interligações utilizando conversores HVDC), esta metodologia proposta busca a melhor relação de curto-circuito trifásico (SCR) no ponto de conexão do conversor de frequência, melhorando a conexão da barra de interesse. O método busca soluções para alocar um único dispositivo de compensação, e soluções alocando simultaneamente dois dispositivos. A metodologia proposta baseia-se na enumeração exaustiva das soluções, e o estudo de caso nos sistemas de 14 e 30 barras do IEEE mostrou a aplicabilidade e funcionalidade da metodologia proposta.<br>This work proposes a methodology to enumerate solutions, which indicate the bar and the reactive power compensation required for the electrical system under analysis, that meet the requirements evaluated by the objective function and the constraints. In this allocation of optimal compensation of reactive power, we obtain the optimal bars and technologies of compensation devices, minimizing the total losses of active power of the network. In weak networks with frequency converters (e.g. for connection of renewable sources, or interconnections using HVDC converters), the proposed methodology seeks the best threephase short-circuit (SCR) relation at the connection point, improving the connection of the new generation. The method looks for solutions to allocate a single compensation device, and solutions to allocate two devices simultaneously. The proposed methodology is based on the exhaustive enumeration of the solutions. A case study carried out in the IEEE 14 and 30 bus systems shows the applicability and performance of the proposed methodology.
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Говоров, Владлен Пилипович. "Підвищення ефективності розподільчих мереж міст в умовах слабкої кореляції графіків навантажень та нелінійності характеристик електроприймачів". Thesis, НТУ "ХПІ", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/21845.
Full textAbstract:
Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.14.02 – "Електричні станції, мережи і системи". Національний технічний університет "Харківський політехничний інститут", Харків 2016.Дисертація присвячена підвищеню ефективності розподільчих електричних мереж міст в умовах нелінійності характеристик на проектному рівні. У роботі визначено особливості режимів розподільчих електричних мереж міст, які полягають в наявності значної величини реактивної потужності та низької кореляції графіків її зміни з графіком активної потужності, а також значній величині завад та спотворень в мережах. За результатами досліджень енергетичних процесів в розподільчих електричних мережах міст доведено, що за умов великого рівня завад та спотворень реактивна потужність спотворень має переважний вплив на режими електричних мереж, і обґрунтовано необхідність роздільного обліку та компенсації реактивної потужності зсуву та реактивної потужності спотворень. На основі дослідження параметрів та режимів вольтододавальних трансформаторів встановлена можливість комплексного розв’язаного вирішення на їх основі питань регулювання напруги та компенсації реактивної потужності в мережах.<br>The thesis for the degree of candidate of technical sciences, specialty 05.14.02 - "Electric stations, networks and systems." National Technical University “Kharkiv Politechnical Institute”, Kharkiv 2016. The thesis is devoted to increased efficiency of electrical distribution networks of cities in terms of nonlinearity characteristics at the project level. The paper based on the study of modes of electrical distribution networks by the methods of physical and mathematical modeling peculiarities modes of electrical distribution networks of cities that are in large size reactive power and low correlation graph of change to the schedule of active power and large size of noise and distortion in networks. According to the research of energy processes in electrical distribution networks of cities proved that with the huge level of noise and distortion reactive power distortion is the dominant influence on modes of electrical networks and the necessity of separate accounting shift reactive power and reactive power distortion. Based on the study parameters and modes voltododavalnyh transformers installed the opportunity to integrated solutions and solved on the basis of voltage control and reactive power compensation in networks.
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Петренко, А. М. "Система електропостачання тепличного комплексу «АсканіяФлора»". Thesis, Чернігів, 2021. http://ir.stu.cn.ua/123456789/25280.
Full textAbstract:
Петренко, А. М. Система електропостачання тепличного комплексу «АсканіяФлора» : випускна кваліфікаційна робота : 141 "Електроенеретика, електротехніка та електромеханіка" / А. М. Петренко ; керівник роботи А. В. Красножон ; НУ "Чернігівська політехніка", кафедра електричної інженерії та інформаційно-вимірювальних технологій. – Чернігів, 2021. – 15 с.<br>Об'єкт дослідження – система внутрішнього електропостачання тепличного комплексу «Асканія-Флора». Мета роботи – спроектувати систему внутрішнього електропостачання нового тепличного комплексу. У магістерському проекті проведено оцінювання режиму роботи діючої системи електропостачання 10 кВ, в результаті чого отримано, що втрати в лініях незначні, а трансформатори працюють без перевантаження. Спочатку була спроба адаптувати діючу систему внутрішнього електропостачання «Асканія-Флора» до збільшення навантаження за рахунок дозавантаження існуючих трансформаторних підстанцій 10/0,4 кВ до номінальних потужностей та компенсації їх навантаження по реактивній потужності по стороні низької напруги. Але дана спроба не дала бажаного результату, тому було розроблено проект електропостачання з новими трансформаторними підстанціями та мережами живлення 10 кВ від розподільчого пункту підстанції «Асканія». Вибране електрообладнання перевірено в аварійному режимі. В проекті було прийнято рішення компенсувати реактивну потужність по стороні 10 кВ. Проведено техніко-економічне обґрунтування запропонованого варіанту системи електропостачання. Спроектовано заземлюючі пристрої для нових трансформаторних підстанцій.<br>The object of study - the internal power supply system of the greenhouse complex "Askania-Flora". The purpose of the work is to design the internal power supply system of the new greenhouse complex. In the master's project, the operation of the existing 10 kV power supply system was evaluated, as a result of which it was found that the losses in the lines are insignificant, and the transformers operate without overload. Initially, there was an attempt to adapt the existing internal power supply system "Askania-Flora" to increase the load by reloading the existing 10 / 0.4 kV transformer substations to rated capacities and compensating for their load on the reactive power on the low voltage side. But this attempt did not give the desired result, so a power supply project was made with new transformer substations and 10 kV power supply networks from the distribution point of the Askania substation. The selected electrical equipment is tested in emergency mode. The project decided to compensate the reactive power on the 10 kV side. Feasibility study of the proposed variant of the power supply system is carried out. Earthing devices for new transformer substations are designed.
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Bernáth, František. "Rozptýlená výroba a jej vplyv na kvalitu dodávok elektrickej energie." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-233625.
Full textAbstract:
This work deals with the deployment of distributed power sources into the electric power grid. The nature of these sources causes that the massive integration may experience problems with power quality in the local context, and also overall reliability of supply in the range of interconnected power systems may be endangered. Work is focused on local voltage quality problems with special emphasis on analysis and design of tools (e.g. reactive power compensation units of power plants or dynamic voltage control by transformers 110/22kV) for voltage control in power distribution systems. These tools should be used as a part of uniform concept of voltage control. The proposed concept is involved.
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Панасюк, Максим Олегович, та Maksym Panasiuk. "Зниження втрат електричної енергії в мережах шляхом вдосконалення методів розрахунку компенсації реактивної потужності". Master's thesis, Тернопільський національний технічний університет імені Івана Пулюя, 2020. http://elartu.tntu.edu.ua/handle/lib/33242.
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Отримав подальший розвиток напрямок створення способів та регуляторів оптимального керування (за критерієм мінімальних втрат), що дозволило адаптувати їх до умов роботи електричних мереж, для яких характерні тривалі недопустимі відхилення напруги, і підтримувати, залежно від режиму електроспоживання, у вузлі задане значення вхідної реактивної потужності або рівень напруги в допустимих межах.<br>У кваліфікаційній роботі магістра отримав подальший розвиток напрямок створення способів та регуляторів оптимального керування реактивною потужністю, що дозволило адаптувати їх до умов роботи електричних мереж, для яких характерні тривалі недопустимі відхилення напруги, і підтримувати, залежно від режиму електроспоживання, у вузлі задане значення вхідної реактивної потужності або рівень напруги в допустимих межах. Також у роботі розроблено регулятор батареї конденсаторів, удосконалено структурну блок-схему системи та алгоритму керування збудженням групи синхронних двигунів, що дозволяє забезпечувати технічні значення вхідної реактивної потужності, які задані енергопостачальною компанією, та регулювати напругу у її вузлах<br>In the qualification work of the master the direction of creation of ways and regulators of optimum control of reactive power that allowed to adapt them to conditions of work of electric networks for which long inadmissible voltage deviations are characteristic, and to support, depending on a mode of power consumption, or voltage level within acceptable limits. The capacitor battery regulator is also developed, the structural block diagram of the system and the excitation control algorithm of a group of synchronous motors is improved, which allows to provide technical values of input reactive power set by the power supply company and to regulate voltage in its nodes<br>ПЕРЕЛІК УМОВНИХ СКОРОЧЕНЬ.... 5
ВСТУП ..... 7
1 АНАЛІТИЧНИЙ РОЗДІЛ ......... 9
1.1 Методи розрахунку компенсації реактивної потужності ... 9
1.2 Статичні тиристорні компенсатори реактивної потужності ..... 13
Висновки до розділу 1 ...... 22
2 ПРОЕКТНО-КОНСТРУКТОРСЬКИЙ РОЗДІЛ ....... 23
2.1 Розроблення регулятора реактивної потужності для мереж
споживачів і ЕПК, для яких характерні тривалі відхилення напруги ...23
2.2 Вдосконалення способу та системи керування збудженням
синхронних двигунів з метою регулювання напруги ..... 29
2.3 Розроблення схем керування СТК ...... 40
Висновки до розділу 2 ..... 47
3 РОЗРАХУНКОВО-ДОСЛІДНИЦЬКИЙ РОЗДІЛ ...... 48
3.1 Загальні умови проведення досліджень режимів роботи СТК .... 48
3.2 Дослідження енергетичного процесу СТК у випадку
параметричної модуляції реактивного елемента ..... 49
Висновки до розділу 3 ...... 58
4 ОХОРОНА ПРАЦІ ТА БЕЗПЕКА В
НАДЗВИЧАЙНИХ СИТУАЦІЯХ ......... 59
4.1 Вимоги пожежної безпеки при гасінні електроустановок ..... 59
4.2 Дослідження стійкості роботи підприємств електроенергетики
в надзвичайних ситуаціях ....... 61
ЗАГАЛЬНІ ВИСНОВКИ ....... 65
ПЕРЕЛІК ПОСИЛАНЬ ..... 66
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Martinák, Rostislav. "Náhrada rotačních synchronních generátorů statickými kompenzátory v podniku Petrochemie." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219404.
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This thesis deals with the reactive power compensation, namely the possibility of reactive power compensation in Petrochemie company using a passive power factor correction system instead of synchronous generators, as part of the contract Kompel company. The thesis analyzes problems of definition of power in circuits with sinusoidal and nonsinusoidal voltages and currents. Furthermore, this thesis describes the power factor correction systems used in the low and medium voltage industrial and distribution networks. The last four chapters contain description of the existing state of power plant in Petrochemie company. There are considered the possibility of use of existing power factor correction system owned by company. The new static power factor correction system is suggested and functionality of power factor correction systems is verified through the simulations.
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Ängquist, Lennart. "Synchronous Voltage Reversal Control of Thyristor Controlled Series Capacitor." Doctoral thesis, KTH, Electrical Systems, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3396.
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<p>Series compensation of transmission lines is an effectiveand cheap method of improving the power transmission systemperformance. Series capacitors virtually reduces the length ofthe line making it easier to keep all parts of the power systemrunning in synchronism and to maintain a constant voltage levelthroughout the system. In Sweden this technology has been inuse since almost 50 years.</p><p>The possibility to improve the performance of the ACtransmission system utilizing power electronic equipment hasbeen discussed a lot since about ten years. Some newsemiconductor based concepts have been developed beside thesince long established HVDC and SVC technologies. The ThyristorControlled Series Capacitor (TCSC) is one such concept. Byvarying the inserted reactance an immediate and well-definedimpact on the active power flow in the transmission line isobtained. Several potential applications, specifically poweroscillation damping, benefit from this capability. The conceptimplied the requirement to design a semiconductor valve, whichcan be inserted directly in the high-voltage power circuit.This certainly presented a technical challenge but thestraightforward approach appeared to be a cost-effectivealternative with small losses.</p><p>It was also realized that the TCSC exhibits quite differentbehaviour with respect to subsynchronous frequency componentsin the line current as compared to the fixed series capacitorbank. This was a very interesting aspect as the risk ofsubsynchronous resonance (SSR), which just involves such linecurrent components, has hampered the use of series compensationin power systems using thermal generating plants.</p><p>The thesis deals with the modelling and control aspects ofTCSC. A simplifying concept, the equivalent, instantaneousvoltage reversal, is introduced to represent the action of thethyristor controlled inductive branch, which is connected inparallel with the series capacitor bank in the TCSC. The idealvoltage reversal is used in the thesis in order to describe andexplain the TCSC dynamics, to investigate its apparentimpedance at various frequencies, as a platform forsynthesizing the boost control system and as the base elementin deriving a linear, small-signal dynamical model of thethree-phase TCSC. Quantitative Feedback Theory (QFT) then hasbeen applied to the TCSC model in order to tune its boostregulator taking into account the typical variation ofparameters that exists in a power system. The impact of theboost control system with respect to damping of SSR is finallybeing briefly looked at.</p><p><b>Keywords:</b>Thyristor Controlled Series Capacitor, TCSC,FACTS, reactive power compensation, boost control, phasorestimation, Quantitative Feedback Theory, subsynchronousresonance, SSR.</p>
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Кушнір, Мирослав Васильович, та Myroslav Kushnir. "Розробка технічних заходів зниження втрат електроенергії в системі електропостачання електроцеху машинобудівного заводу". Master's thesis, Тернопільський національний технічний університет імені Івана Пулюя, 2019. http://elartu.tntu.edu.ua/handle/lib/29685.
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In diploma paper solved the practical problem of reducing electric power losses in the electric power supply system of the electric shop and the enterprise as a whole.
Conducted research the reduce electricity losses at the enterprise.
Calculations of electrical loads of power and lighting consumers of the electric shop and the enterprise were carried out.
Determined the value of the required reactive power from the grid in modes of its maximum loads and conducted compensation of reactive power.
The calculations of short-circuit currents have been carried out and the selection of protective equipment has been made.
Carried the calculations the cables on the side of 10 kV of the shop transformers on thermal stability and change of the cross-sectional area of the wires was substantiated and the selection of switches on the 110 kV and 10 kV sides was made.
The calculation of relay protection of transformers of the main lowering substation with the choice of equipment was carried out.<br>У дипломній роботі вирішено практичну проблему зниження технічних втрат електроенергії в системі електропостачання електричного цеху та підприємства в цілому.
Проведені дослідження щодо зниження втрат електроенергії на підприємстві.
Проведені розрахунки електричних навантажень силових та освітлювальних споживачів електричного цеху та підприємства.
Визначено величини необхідної реактивної потужності з енергосистеми в режимах її максимальних навантажень та здійснена компенсація реактивної потужності.
Проведені розрахунки струмів короткого замикання та здійснено вибір захисного обладнання.
Проведена перевірка кабелів на стороні 10 кВ цехових трансформаторів на термічну стійкість та обґрунтовано зміну площі січення проводів та здійснено вибір вимикачів на сторонах 110 кВ та 10 кВ.
Проведений розрахунок релейного захисту трансформаторів головної понижувальної підстанції з вибором обладнання.<br>ВСТУП …7
1 АНАЛІТИЧНА ЧАСТИНА ...9
1.1 Аналіз технічних заходів зниження втрат електричної енергії промислових підприємств …9
1.2 Загальна характеристика електричного цеху та системи електропостачання машинобудівного заводу …13
1.3 Висновки до першого розділу …15
2 НАУКОВО-ДОСЛІДНА ЧАСТИНА …16
2.1 Моделі керування конденсаторними пристроями …16
2.2 Обґрунтування вибору місця встановлення КП в електричному цеху підприємства …17
2.3 Висновки до другого розділу …22
3 ТЕХНОЛОГІЧНА ЧАСТИНА …23
3.1 Розрахунок електричних навантажень електричного цеху ...23
3.2 Розрахунок освітлювального обладнання електричного цеху …26
3.3 Розрахунок електричних навантажень по підприємству …29
3.4 Розрахунок електричної мережі підприємства …34
3.5 Висновки до третього розділу …38
4 ПРОЕКТНО-КОНСТРУКТОРСЬКА ЧАСТИНА …40
4.1 Розрахунок струмів короткого замикання …40
4.2 Вибір комутаційного та захисного обладнання …44
4.3 Розрахунок релейного захисту трансформаторів ГПП …54
4.4 Висновки до четвертого розділу …60
5. СПЕЦІАЛЬНА ЧАСТИНА …61
5.1 Аналіз видів компенсації реактивної потужності та використання конденсаторних установок …61
5.2 Розрахунок компенсації реактивної потужності та вибір конденсаторних установок …62
5.3 Висновки до п’ятого розділу …69
6 ОБГРУНТУВАННЯ ЕКОНОМІЧНОЇ ЕФЕКТИВНОСТІ...70
6.1 Вибір варіантів трансформаторів ГПП …70
6.2 Техніко-економічне обґрунтування схеми зовнішнього електропостачання підприємства …72
6.3 Розрахунок техніко-економічних показників схем зовнішнього електропостачання за варіантами …80
7 ОХОРОНА ПРАЦІ ТА БЕЗПЕКА В НАДЗВИЧАЙНИХ СИТУАЦІЯХ...82
7.1 Заходи з охорони праці та техніки безпеки на ГПП …82
7.2 Заходи щодо підвищення стійкості роботи трансформаторної підстанції за умов надзвичайних ситуацій …89
8 ЕКОЛОГІЯ …93
8.1 Екологічний безпека машинобудівного комплексу …93
8.2 Методи забезпечення екологічної безпеки підприємств машинобудівної галузі …94
ЗАГАЛЬНІ ВИСНОВКИ ДО ДИПЛОМНОЇ РОБОТИ …97
ПЕРЕЛІК ПОСИЛАНЬ …99
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Говоров, Владлен Пилипович. "Підвищення ефективності розподільчих мереж міст в умовах слабкої кореляції графіків навантажень та нелінійності характеристик електроприймачів". Thesis, Харківський національний університет міського господарства ім. О. М. Бекетова, 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/21852.
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Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.14.02 – "Електричні станції, мережи і системи". Національний технічний університет "Харківський політехничний інститут", Харків 2016.Дисертація присвячена підвищеню ефективності розподільчих електричних мереж міст в умовах нелінійності характеристик на проектному рівні. У роботі визначено особливості режимів розподільчих електричних мереж міст, які полягають в наявності значної величини реактивної потужності та низької кореляції графіків її зміни з графіком активної потужності, а також значній величині завад та спотворень в мережах. За результатами досліджень енергетичних процесів в розподільчих електричних мережах міст доведено, що за умов великого рівня завад та спотворень реактивна потужність спотворень має переважний вплив на режими електричних мереж, і обґрунтовано необхідність роздільного обліку та компенсації реактивної потужності зсуву та реактивної потужності спотворень. На основі дослідження параметрів та режимів вольтододавальних трансформаторів встановлена можливість комплексного розв’язаного вирішення на їх основі питань регулювання напруги та компенсації реактивної потужності в мережах.<br>The thesis for the degree of candidate of technical sciences, specialty 05.14.02 - "Electric stations, networks and systems." National Technical University “Kharkiv Politechnical Institute”, Kharkiv 2016. The thesis is devoted to increased efficiency of electrical distribution networks of cities in terms of nonlinearity characteristics at the project level. The paper based on the study of modes of electrical distribution networks by the methods of physical and mathematical modeling peculiarities modes of electrical distribution networks of cities that are in large size reactive power and low correlation graph of change to the schedule of active power and large size of noise and distortion in networks. According to the research of energy processes in electrical distribution networks of cities proved that with the huge level of noise and distortion reactive power distortion is the dominant influence on modes of electrical networks and the necessity of separate accounting shift reactive power and reactive power distortion. Based on the study parameters and modes voltododavalnyh transformers installed the opportunity to integrated solutions and solved on the basis of voltage control and reactive power compensation in networks.
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Semensato, Marcelo. "Alocação de capacitores em redes de distribuição desequilibradas para minimizar as perdas de energia elétrica e o desequilíbrio /." Ilha Solteira, 2018. http://hdl.handle.net/11449/180445.
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Orientador: Antonio Padilha Feltrin<br>Resumo: As redes elétricas de distribuição em sua maioria apresentam cargas elétricas desequilibradas. Por isso é necessário estudar as potências envolvidas em sistemas trifásicos desequilibrados e a compensação das mesmas. O desequilíbrio aumenta as perdas elétricas e diminui o fator de potência da rede elétrica. Esse trabalho propõe a compensação da potência reativa e do desequilíbrio na rede com a finalidade da diminuição das perdas elétricas e a compensação das componentes de sequência desequilibradas da corrente. A utilização da teoria da potência efetiva em sistemas desequilibrados permite calcular as potências reativas e de desequilíbrio, sendo estas as potências compensadas no método proposto. A teoria da potência efetiva mede a eficiência dos métodos testados. Os objetivos da compensação do desequilíbrio são reduzir as perdas elétricas no neutro e o fator de desequilíbrio da tensão, além da potência de desequilíbrio na rede, potência exclusiva do desequilíbrio e que não realiza trabalho. O método proposto para compensação do desequilíbrio e dos reativos na rede de distribuição a quatro fios consiste na alocação de capacitores em delta ou estrela nas barras trifásicas. O método proposto é comparado com dois métodos existentes na literatura. A comparação entre os métodos permite constatar que o método proposto é mais eficiente na redução do desequilíbrio conjuntamente com a compensação das perdas elétricas. Quanto maior é o desequilíbrio da rede elétrica maior é a vantagem da ... (Resumo completo, clicar acesso eletrônico abaixo)<br>Abstract: Distribution electrical networks mostly have unbalanced electrical loads. Therefore it is necessary to study the powers involved in unbalanced three-phase systems and their compensation. The unbalance increases the power losses and decreases the power factor of the electrical network. This work proposes the compensation of the reactive power and the unbalance in the network with the purpose of reducing the power losses and the compensation of the unbalanced sequence components of the current. The use of the effective power theory in unbalanced systems allows to calculate the reactive and unbalanced power, these being the powers compensated in the proposed method. Effective power theory measures the efficiency of the methods tested. The objectives of the unbalance compensation are to reduce the power losses in the neutral and the unbalance factor of the voltage, besides the unbalanced power in the network, exclusive power of the unbalance and that do not realize work. The proposed method for unbalance and reactive compensation in the four-wire distribution network consists of the allocation of delta or wye-connected capacitors to the three-phase bus. The proposed method is compared with two methods in the literature. The comparison between the methods allows to verify that the proposed method is more efficient in reducing the unbalance together with the compensation of the power losses. The greater the unbalance in power network, the greater the advantage of the compensation b... (Complete abstract click electronic access below)<br>Doutor
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Krátký, Michal. "Analýza toků jalového výkonu v distribuční soustavě." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-220684.
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This thesis is focused on issues with transmission of reactive power though the distribution line of E.ON area. The goal is to find out where and in what rate are overflows of reactive power and to project the correctional steps to minimize this overflow. In this solution, there were used data of dispatcher measurement, which were processed by created source code in Matlab. The processing was analyzed for final conclusion. There were discovered shortages in overflow of reactive power in transfer between distribution and transmission line and in unsuitably regulated capacity power factor in Planá power plant and wrong automatic regulation of turns in 440/110kV substation Dasný. The action to minimize overflows of reactive power was projected by decompensation reactor placed in T101 and T102 transformers in substation Tábor.
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Souza, Wallace Gabriel de. "Estudo de um inversor fotovoltaico para controle e compensação de reativos e harmônicos." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/154529.
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Previous issue date: 2018-05-18<br>Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)<br>Esta dissertação apresenta o desenvolvimento e as simulações computacionais de um inversor fotovoltaico de 2,0 kVA para o controle da potência reativa na rede de distribuição, de modo que haja compensação ativa do fator de potência e aumento da qualidade da energia no local da instalação da planta. Para atingir este objetivo, por meio do ambiente de desenvolvimento do MATLAB/Simulink®, o controle da potência ativa foi realizado pelo ajuste do ângulo entre a tensão da rede e a tensão gerada pelo inversor, por meio do equilíbrio do potencial do barramento CC (proveniente do gerador fotovoltaico). A potência reativa, por sua vez, foi ajustada pela amplitude da tensão do ponto de acoplamento de uma carga local. Além disto, utilizaram-se controladores proporcionais-ressonantes nas malhas de tensão e corrente do conversor trifásico, com finalidade de mitigar as correntes harmônicas de cargas não-lineares que podem depreciar o fator de potência. Foi implementado, também, um conversor CC-CC isolado full-bridge do tipo boost com potência nominal de 1,8 kW, responsável por rastrear o ponto de máxima potência dos módulos fotovoltaicos. Os resultados obtidos permitiram a avaliação do desempenho dos controladores e a observação da conservação, pelo inversor, do fator de potência da rede próximo da unidade para situações com variações acentuadas da carga e da irradiação solar, bem como para os casos com a presença de cargas não-lineares no sistema. Com isso, o perfil de tensão entregue à carga é aproximadamente senoidal, com baixa distorção harmônica.<br>This dissertation presents the development and computational simulations of a 2.0 kVA photovoltaic inverter for the control of the reactive power in the distribution network, so that there is active power factor compensation and an increase in the quality of the energy at the installation site plant. In order to reach this objective, the MATLAB/Simulink® development environment was used to control the active power by adjusting the angle between the grid voltage and the voltage generated by the inverter, by means of the potential balance of the DC (from the photovoltaic generator). The reactive power, in turn, was adjusted by the amplitude of the voltage of the coupling point of a local load. In addition, resonant-proportional controllers were used in the voltage and current loops of the three-phase converter, in order to mitigate the harmonic currents of non-linear loads that may depreciate the power factor. A full-bridge, full-bridge boost converter with nominal power of 1.8 kW was also implemented, responsible for tracking the maximum power point of the photovoltaic modules. The results obtained allowed the evaluation of the performance of the controllers and the observation of the conservation by the inverter of the power factor of the network close to the unit for situations with marked variations of the load and the solar irradiation, as well as for the cases with the presence of loads in the system. Thus, the voltage profile delivered to the load is approximately sinusoidal, with low harmonic distortion.<br>2016/03734-3
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Benedito, Ricardo da Silva. "Análise de um mecanismo de compensação de reativos incorporado aos inversores de um sistema fotovoltaico conectado à rede elétrica." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/106/106131/tde-16122014-000110/.
Full textAbstract:
No Brasil, quando uma unidade consumidora (UC) sob regime de microgeração ou de minigeração distribuída tem parte ou a totalidade da sua demanda por potência ativa suprida pela planta geradora, mas sua demanda por potência reativa é atendida exclusivamente pela rede elétrica, verifica-se uma aparente deterioração do fator de potência dessa UC, sob a ótica da concessionária. Esse efeito decorre do fato de que o fator de potência, de acordo com a regulamentação vigente, é determinado apenas a partir das medições dos fluxos de potência ativa e reativa trocados entre a UC e a rede elétrica e não também entre a planta geradora e UC. Para consumidores do Grupo A (tensão de fornecimento igual ou superior a 2,3 kV) nessa situação, de acordo com o perfil da carga, pode haver cobrança por excedentes de reativos, constituindo-se assim uma barreira. Especificamente no caso de sistemas fotovoltaicos conectados à rede, existe a possibilidade de se utilizar os próprios inversores c.c.-c.a para suprir a demanda de reativos da UC e, dessa forma, minimizar o problema apresentado. Com o objetivo de se avaliar essa alternativa no contexto brasileiro, tendo-se em vista condições reais de operação e os limites normativos de injeção de potência reativa para inversores de sistemas fotovoltaicos, foi realizado um estudo de caso de uma planta fotovoltaica instalada no telhado do prédio da Administração do Instituto de Energia e Ambiente da Universidade de São Paulo. O estudo mostrou que a compensação realizada por meio do inversor selecionado evitou a cobrança de excedentes de reativos sem afetar de forma significativa a produtividade do sistema fotovoltaico. Do ponto de vista elétrico, verificou-se que a injeção de reativos pelo inversor não provocou variações significativas de tensão no ponto de acoplamento ou no alimentador e, ainda, se verificou considerável liberação de capacidade do sistema supridor da concessionária. Dessa forma, a análise dos resultados indica uma tendência a se considerar a compensação de reativos proporcionada pelo próprio inversor a opção mais viável para se lidar com os excedentes de reativos, comparativamente a métodos convencionais de compensação ou à situação em que nenhuma ação compensatória seja implementada.<br>In Brazil, when a consumer unit (CU) under a distributed microgeneration or minigeneration scheme has part or all of its demand for active power supplied by the generating plant, but its demand for reactive power is served exclusively by the grid, the power factor of this CU appears deteriorated, from the perspective of the utility. This effect is due to the fact the power factor, according to the current regulations, is determined only from measurements of the flows of active and reactive power exchanged between the UC and the grid and not also between the generating plant and UC. Users of group A (supply voltage equal to or greater than 2.3 kV) in this situation, according to the CU load profile, may be charged due the reactive power excess, thus constituting a barrier. Specifically in the case of grid-connected photovoltaic systems, there is the possibility of using the d.c.- a.c. inverters to suply the CU reactive power demand and, thus, minimizing the presented problem. In order to evaluate this alternative in the Brazilian context, keeping in view real operating conditions and regulatory limits for the reactive power injection for photovoltaic inverters, we conducted a case study with a photovoltaic plant installed on the roof of the University of São Paulo Institute for Energy and Environment administration building. The study showed that the compensation performed by the selected inverter prevented the reactive power excess charging without affecting significantly the photovoltaic system productivity. From an electrical point of view, it was found that the injection of reactive power by the inverter did not cause significant voltage variations at the coupling point or at the transformer and, additionally, there was a significant release in the utility suply system capacity. Thus, the analysis results indicates a tendency to consider the compensation provided by the inverter itself the most viable option for dealing with the surplus of reactive power compared to conventional compensation methods or to the situation in which no compensatory action is implemented.
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Ткаченко, Ю. М. "Оптимізація розміщення батарей конденсаторів в низьковольтних мережах". Master's thesis, Сумський державний університет, 2019. http://essuir.sumdu.edu.ua/handle/123456789/76544.
Full textAbstract:
Розглянуто питання зі зменшення втрат електричної енергії в мережах розрахунків з метою оптимізації розміщення конденсаторних установок на ТП 10/0,4 кВ. Обчислено втрати схеми в
режимі без КРП і з установкою НБСК на шинах 0,4 кВ. Визначена економічна ефективність, час за який окупиться НБСК, які застосовуються для установки на шинах 10 кВ и 0,4 кВ.
Проаналізовано інструкції охорони праці при монтажі систем електропостачання та освітлення; розрахований заземлюючий контур підстанції.