Archive for the ‘Interconnection’ Category
To illustrate how this impacts the operation of the electricity grid, consider five different levels of available electricity production from RES, as shown in Figure. Note that there is not only a capacity of power towards the storage (charging the storage) but also a capacity of power from the storage to the grid (discharging the storage). It is part of the role of the system operator to decide which of the two should be chosen at any moment in time. Some thoughts are given below, based on the supply capacity in relation to the demand.
Supply level 1. The total supply capacity, directly from renewable sources plus by discharging the storage, is not enough to cover the power demand. The result is that not all the power demand can be fulfilled. All the available storage discharging capacity will be used to limit the amount of demand that is not fulfilled.
Supply level 2. The amount of supply capacity directly from renewables is not sufficient to cover the power demand, but by using part of the discharging capacity of the storage the power demand can be supplied. The remaining storage capacity can either be saved for later use or be used to cover some of the energy demand. This will be an optimization issue, where the state of charge of the storage, the expected future demand and the expected future production from renewables will have to be considered.
Supply level 3. The amount of supply capacity directly from renewables is sufficient to cover the total power demand. The remainder can be used to supply part of the energy demand and/or to charge the storage. When there is sufficient energy in the storage, the stored energy can even be used to supply the total energy demand. The optimisation of the charging/discharging of the storage versus supplying the energy demand is one of the tasks of the system operator.
Supply level 4. The amount of supply capacity directly from renewables exceeds the sum of power demand and energy demand. In that case the total power demand will be supplied and the remainder will be used to charge the storage.
Supply level 5. The amount of supply capacity directly from renewables exceeds to sum of power demand, energy demand, and charging capacity of the storage. In that case all demand should be fulfilled and the remaining amount of renewable energy will be curtailed.
Source: Antonio Moreno-Munoz. “Large Scale Grid Integration of Renewable Energy Sources”. The Institution of Engineering and Technology. 2017.
Dr. Jorge Mírez
e-mail: jmirez@uni.edu.pe
WebSite: http://www.geocities.ws/jorgemirez/
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“Energy Management of Distributed Resources in Microgrids”. J. L. Mírez, H.R. Chamorro, C.A. Ordonez, R. Moreno. 2014 IEEE 5th Colombian Workshop on Circuits and Systems (CWCAS).
DOI: 10.1109/CWCAS.2014.6994607
“Simulation of DC Microgrid and Study of Power and Battery Charge/Discharge Management”. Jorge Mírez, Luis Hernández-Callejo, Manfred Horn, Luis Miguel Bonilla. DYNA Ingeniería e Industrial. November 2017 – Volume: 92 – Pages: 673-679.
DOI: http://dx.doi.org/10.6036/8475
“A modeling and simulation of optimized interconnection between DC microgrids with novel strategies of voltage, power and control”. Jorge Mírez. 2017 IEEE Second International Conference on DC Microgrids (ICDCM). DOI: 10.1109/ICDCM.2017.8001098
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
Invitación a Defensa de Tesis: “CONTROL, OPTIMIZACION Y GESTIÓN DE MICRORREDES DE CORRIENTE CONTINUA” para optar el Grado Académico de Doctor en Ciencias con mención en Física. Elaborado por Jorge Luis Mírez Tarrillo bajo el asesoramiento de Dr. Manfred – Universidad Nacional de Ingeniería y Dr. Joseph Guerrero – Universidad de Aalborg. Se realizará en el Auditorio de la Oficina General de Posgrado en el Pabellon Central de la Universidad Nacional de Inngeniería (Distrito del Rímac, Lima, Perú) el jueves 03 de mayo del 2018 a las 11 AM (hora de Perú)
Link del evento :
https://www.facebook.com/events/1630793593706448/
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My Paper: Jorge Mirez. A modeling and simulation of optimized interconnection between DC microgrids with novel strategies of voltage, power and control. Published in: 2017 IEEE Second International Conference on DC Microgrids (ICDCM). Nuremburg, Germany – link to IEEExplore
Abstract:
The interconnection between DC microgrids has been studied through the modeling and simulation of two DC microgrids and utility network with independent connection to each microgrid. Each microgrid has generation sources, storage source, electrical charges, two points of common coupling (one with the utility network and other with the neighboring microgrid) and a central controller. By performing the simulations and searching for new ways in which the interconnection can be made, the following contributions are reached: (a) although a nominal voltage is present on the DC microgrid bus, it becomes necessary to have three mini-voltage scales (one for the micro-sources, another for the storage sources and a third for AC/DC converter output that connects the utility supply and DC microgrid bus); (b) the power to avoid being heavily dependent on random variables requires temporary storage at the generation sources and that electrical loads define a very stable demand and clearance for certain period of time (of a few minutes), said period would be a new time scale of microgrid operation; (c) the cost associated with generation and storage sources must be optimized for the microgrids operation on the new unit of measurement and for which linear programming techniques have been used, and (d) it representing new coordination actions for tertiary control among central controllers of the microgrids. The new strategies of control, voltage and power will serve to propose and study new designs of: topologies of the electrical network, interconnection devices between microredes and other topics.
Link to Complete Article into IEEExplore: http://ieeexplore.ieee.org/document/8001098/
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