Archive for the ‘Power Electronic’ Category
Todo artefacto, componente, máquina, sistema, etc… presenta un progresivo envejecimiento que conlleva a la falla de los equipos los cuales se van registrando durante los años de funcionamiento y con esa información se crea histogramas como el que se muestra en el presente post. Obviamente mientras más fallas se presentan la curva de distribución se forma mejor, y a partir de ello se puede normalizar y tener una función de probabilidad característica de la marca y modelo del equipo, máquina, etc. Elaborado con MATLAB para ustedes queda la gráfica.
Dr. Jorge Luis Mírez Tarrillo – PERU
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E-mail: jmirez@uni.edu.pe
ESPOCH 50 años ‘Congreso Internacional ESPOCH 50 años’. Un espacio de investigación con expositores de todo el mundo.
Expositor: Dr. Jorge Luis Mírez Tarrillo
Tema: Microrredes Eléctricas
Institución: Universidad Nacional de Ingeniería, Lima, Perú.
https://fb.watch/cGlrOoPc9s/
Dr. Jorge Luis Mírez Tarrillo – PERU
Facebook http://www.facebook.com/jorgemirezperu
Linkedin https://www.linkedin.com/in/jorge-luis-mirez-tarrillo-94918423/
Scopus ID: https://www.scopus.com/authid/detail.uri?authorId=56488109800
Google Scholar: https://scholar.google.com/citations?user=_dSpp4YAAAAJ
E-mail: jmirez@uni.edu.pe
The figure in this post shows the simplest type of circuit in which the series capacitor is protected by a self-triggered spark gap. The spark gap is set to flashover at a given voltage, usually in the range of 2.0–3.5 per unit (where 1.0 per unit is equal to the crest voltage produced across the series capacitor at rated current). But, the spark gap may not fire for low-current faults. Therefore, the line protection scheme must also perform properly with the series capacitor still in operation. The bypass breaker is used by an operator to remove the capacitor bank from the service for maintenance and for reinserting the capacitor bank into the service following these intentional removals
Disponible / Available en:
https://www.amazon.com/Introducción-Modelamiento-Simulación-Microredes-Energía/dp/3639635299
Dear audience. I am very happy in to write this post 1000 :)D . During many years, it has been a both exciting and hard work in read, understand, programming, modeling, simulations and analysis of results. The figure is a little photovoltaic power plant with its respective solar radiation. It has been implemented from mathematical models of thesys and books. The model is adaptable to PV plant of more power. Made in Matlab of MathWorks Inc.
The dc-bus microgrid link the diferent component of the microgrid both loads as sources. The figure is a general representation with conextion to AC-grid, wind turbine, PV solar plant, DC and AC loads, Batteries, fluwheel, micro turbine, AC/DC converser, DC/AC converser and DC/DC converser.
Source:
S. Vimalraj, P. Somasundaram, “Fault Detection, Isolation and Identification of Fault Location in Low-Voltage DC Ring Bus Microgrid System,” Int. J. Advanced Res. in Electrical, Electronics and Instr. Eng. vol. 3, special iss. 2, pp: 570-582, Apr. 2014
The second important concept that is popular for the newly developed and installed wind turbines is shown in Figure. It introduces a full-scale power converter to interconnect the power grid and stator windings of the generator, thus all the generated power from the wind turbine can be regulated. The asynchronous generator, wound rotor SG (WRSG) or permanent magnet SG (PMSG) have been reported as solutions to be used. The elimination of slip rings, simpler or even eliminated gearbox, full power and speed controllability as well as better grid support ability are the main advantages compared with the DFIG-based concept. The more stressed and expensive power electronic components as well as the higher power losses in the converter are, however, the main drawbacks for this concept.
Source:
Frede Blaabjerg and Ke Ma “Future on Power Electronics for Wind Turbine Systems” IEEE Journal of Emerging and Selected Topics in Power Electronics, Vol. 1, No. 3, September 2013
This wind turbine concept is the most adopted solution nowadays and it has been used extensively since 2000s. As shown in Figure, a PEC is adopted in conjunction with the DFIG. The stator windings of DFIG are directly connected to the power grid, whereas the rotor windings are connected to the power grid by the converter with normally 30% capacity of the wind turbine. In this concept, the frequency and the current in the rotor can be flexibly regulated and thus the variable speed range can be extended to a satisfactory level. The smaller converter capacity makes this concept attractive seen from a cost point of view. Its main drawbacks are however, the use of slip rings and the challenging power controllability in the case of grid faults—these disadvantages may comprise the reliability and may be difficult to completely satisfy the future grid requirements
Source:
Frede Blaabjerg and Ke Ma «Future on Power Electronics for Wind Turbine Systems» IEEE Journal of Emerging and Selected Topics in Power Electronics, Vol. 1, No. 3, September 2013
Classical HVDC transmission systems [as shown in Figure (a)] are based on the current source converters with naturally commutated thyristors, which are the so-called linecommutated converters (LCCs). This name originates from the fact that the applied thyristors need an ac voltage source in order to commutate and thus only can transfer power between two active ac networks. They are, therefore, less useful in connection with the wind farms as the offshore ac grid needs to be powered up prior to a possible startup. A further disadvantage of LCC-based HVDC transmission systems is the lack of the possibility to provide an independent control of the active and reactive powers. Furthermore, they produce large amounts of harmonics, which make the use of large filters inevitable. Voltage-source converter (VSC)-based HVDC transmission systems are gaining more and more attention not only for the grid connection of large offshore wind farms. Figure (b) shows the schematic of a VSC-based HVDC transmission system
Source:
Juan Manuel Carrasco, Leopoldo García Franquelo, Jan T. Bialasiewicz, Eduardo Galván, Ramón C. Portillo Guisado, Ángeles Martín Prats, José Ignacio León and Narciso Moreno-Alfonso “Power-Electronic Systems for the Grid integration of Renewable Energy Sources: A Survey”. IEEE Transactions on Industrial Electronics, Vol. 53, No. 4, August 2006
The figure shows the scheme of a full power converter for a wind turbine. The machine-side three-phase converter works as a driver controlling the torque generator, using a vector control strategy. The grid-side three-phase converter permits windenergy transfer into the grid and enables to control the amount of the active and reactive powers delivered to the grid. It also keeps the total-harmonic-distortion (THD) coefficient as low as possible, improving the quality of the energy injected into the public grid. The induction generator of wind turbine is connected to a voltage-source inverter (VSI) used as a rectifier
Source:
Juan Manuel Carrasco, Leopoldo García Franquelo, Jan T. Bialasiewicz, Eduardo Galván, Ramón C. Portillo Guisado, Ángeles Martín Prats, José Ignacio León and Narciso Moreno-Alfonso “Power-Electronic Systems for the Grid integration of Renewable Energy Sources: A Survey”. IEEE Transactions on Industrial Electronics, Vol. 53, No. 4, August 2006
Sun –> energy provided from photovoltaic energy plant.
Wind –> similar from wind turbine(s)
Batt –> similar from battery bank
ene –> similar injected from electrical network external or utility electric network
In other image in red is the total suministed for this sources and red line is the demand. Other images is cost, evoluction of energy supply from each source and more details. It is made for me (Jorge Mírez) in Matlabb/Simulink and I utilized concept of linear programming. Image is from my destokp laptop.
Transient changes in load power demand may result from faults in transmission line or load switching. For instance, a 75-kW Honeywell micro-turbine took about 35 s to respond for a 50%change in power demand under the grid-connected mode of operation.On the other hand, some fuel cells require about 10 s for a 15% change in power output.Furthermore, a fuel cell also has a recovery period of a few minutes to establish equilibrium before it can meet another step change in power output. The typical response that can be expected of a micro-turbine for a step change in load demand is illustrated in Figure. In the figure, PL denotes the load power demand, PS is the response of the micro-turbine, and (PL-PS) is the short age in power that needs to be supplied through some means. Inthe grid-connected mode of operation, the grid supplies the shortage in power until the micro-source responds to a step changein power demand. However, in the island mode of operation, this sudden demand can be met only if
additional storage is included in the MSDG system.
Source:
G. Venkataramanan, M.S. Illindala, C. Houle, and R.H. Lasseter. «Hardware Development of a Laboratory-Scale Microgrid Phase 1—Single Inverter in Island Mode Operation». NREL. November 2002 • NREL/SR-560-32527
Inthe recent past, dramatic improvements in productivity have been realized in the high technology sector as well as in the traditional industries. For the electric power supply to these industries, this hasled to a concomitant increase in the number of loads that are sensitive to power quality. Some of the industries that have such large sensitive loads include semiconductor manufacturing, textile mills, paper millsand plastic injection molding.Of course, a number of smaller but equally critical loads such as computers and electronic data processing equipment are also sensitive to power quality.Thetolerance
levels of computer equipment are specified by the Information Technology Industry/Computer and Business Equipment Manufacturers’ Association (ITI/CBEMA) curves. Figure illustrates theCBEMA curves. This figure gives thepercent of nominal voltage versus duration in (60-Hz) cycles. The CBEMA curves represent the boundary of the ac input voltage envelope that can be tolerated (typically) by most
computer-based equipment. The upper curve represents the maximum voltage below which the equipment will continue to function normally. The lower curve is the minimum voltage above which the equipment will continue to function normally.
As seen in Figure, the steady state range of tolerance for computer equipmentis ±10% from the nominal voltage, i.e., the equipment continues to operate normally when sourced by any voltages in this range for an indefinite period of time. Similarly, voltages wells to a magnitude of 120% of the nominal value can be tolerated for about 0.5 s or 30 cycles; voltage sags to 80% of nominal for 10 s, or 600 cycles, can be tolerated. When the supply voltage is outside the boundaries of the susceptibility curves, improvement of the quality of power supplied to sensitive loads is essential to avoid a possible failure in their operation.
Source:
G. Venkataramanan, M.S. Illindala, C. Houle, and R.H. Lasseter. «Hardware Development of a Laboratory-Scale Microgrid Phase 1—Single Inverter in Island Mode Operation». NREL. November 2002 • NREL/SR-560-32527
One question that most system operators are concerned with is the optimised DG penetration level. Relationship regarding different cost models between optimum DG penetration level and interruption frequency is indicated in Figure.
Optimum micro-source penetration level is positive related with the interruption frequency without DG penetration; especially for average interruption costs, the relationship is almost linear. This relationship is important for systemplanning; as the system interruption frequency without DG penetration is generally known, the system operator is able to roughly determine of the optimum DG penetration level from reliability point of view
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