18 research outputs found
Dynamic Pricing for Microgrids Energy Transaction in Blockchain-based Ecosystem
Microgrid (MG) is an efficient platform to integrate distributed energy resources in distribution networks. The operation of MG is also expected to take advantage of emerging smart grid technologies to improve operation and robustness. Among these emerging technologies, blockchain technology provide a big potential to rule the energy transaction in an innovative way. In this paper, a physical architecture of the ecosystem with MGs is firstly presented. Moreover, as the main parts of the blockchain technology, the operation of distributed ledger and smart contracts are introduced in the transaction process. Considering dynamic pricing scheme in the process of energy transaction in the ecosystem, we model the energy transaction between MGs and distribution system operator (DSO) to decide the trading amount and price of the energy. The welfare maximization mathematical model is established accordingly, and the formulated dual problem will be used to find the shadow price of selling renewable energy to grid and real-time retailer price from DSO. Finally, with the deployment of distribution ledger, the energy transaction process can be fully recorded, and transaction execution can be achieved with the help of smart contracts. In light of the mentioned perspective, beside demonstrated benefit brought to both MGs and DSO, the energy transaction and management based on the blockchain will result in higher reliability and improved auditability in the ecosystem
Synchronization of power inverters in islanded microgrids using an FM-modulated signal
"(c) 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works."A microgrid can operate in island mode, isolated
from the main grid during certain time intervals. When operated
in island mode, the electronic converters of the microgrid
must keep the voltage and frequency of the microgrid inside
the desired range. The converters of a microgrid can be classified
into three groups: 1) grid-feeding; 2) grid-supporting; and
3) grid-forming power converters. The grid-forming converters
operate as a voltage source, and require an external synchronization
signal provided by the microgrid central controller. Both
the noise and the delay in the synchronization signals received
by the grid-forming converters are critical issues, which deteriorate
the quality of the microgrid voltage and may overload
those converters. The synchronization signals must be robust and
suitable for operating in noisy environments. In this paper, the
synchronization signal is frequency-modulated to be transmitted,
being robust against noise. The transmission is done through an
industrial RS-485 line with a low delay. The demodulation is performed
with a low computational load by the control processors
of the grid-forming power converters.This work was supported in part by the Spanish Ministry of Economy and Competitiveness under Grant ENE2015-64087-C2-2-R, and in part by the European Regional Development Fund.Patrao Herrero, I.; González Medina, R.; Marzal-Romeu, S.; Garcerá Sanfeliú, G.; Figueres Amorós, E. (2017). Synchronization of power inverters in islanded microgrids using an FM-modulated signal. IEEE Transactions on Smart Grid. 8(1):503-510. https://doi.org/10.1109/TSG.2016.2574038S5035108
“Estrategia de control robusto descentralizado para una micro-red aislada con generación distribuida acoplada para mejorar la estabilidad de voltaje”
El constante avance de la tecnología
requiere una gran cantidad de energía, por
ello se ha propuesto la inclusión de fuentes
de energía renovable (RES) cerca de los
centros de carga. Estas RES son
implementadas también en sectores donde
el sistema eléctrico convencional no es
capaz de llegar, de esta manera se
garantiza el abastecimiento de energía
eléctrica a toda la población. Sin embargo,
la implementación de estos nuevos
sistemas implica retos de control para que
su funcionamiento sea correcto,
indiferente que la Micro-red funcione de
forma conectada o aislada a la red
convencional.
Este trabajo presenta una novedosa
estrategia de control de Micro-redes
aisladas, basado en el control jerárquico y
control droop modificado. Esta estrategia
robusta permite mejorar la estabilidad de
voltaje y su comportamiento transitorio.
Se implementa una Micro-red de
referencia con dos fuentes fotovoltaicas
con valores nominales. Lo que permite
verificar el desempeño de la estrategia
propuesta comparando con un controlador
PI convencional.Technological advances demand a huge
amount of electricity, therefore
Renewable Energy Resources (RES) must
be near the electrical demand is huge, in
addition they are implemented in rural
places, where electric utility is not able to
provide the service. However, the
implementation of these new systems
implies facing new challenges for the
correct operation of Microgrid connected
or islanded from the conventional system.
This research presents a novel control
strategy for islanded Microgrids, based on
hierarchical control and modified droop
control. The robust control strategy
presented allows stability voltage
improvement and its transient behavior.
Which subscribes to verify the
performance of the proposed strategy
compared with a conventional PI
controller
Control strategy for direct voltage and frequency stabilityenhancement in HVAC/HVDC grids
Direct voltage fluctuations due to the presence of relatively large DC reactors (as an essen-tial part of HVDC breakers), lack of inertia, and unwanted frequency fluctuations in theAC side of HVDC grids, have major consequences on the stability of HVAC/HVDC grids.The use of the DC Power System Stabilizer (DC-PSS) can damp and eliminate voltageoscillations caused by the presence of the DC reactors. However, DC-PSS cannot addressthe issues of inertia and unwanted frequency fluctuations. A method to improve inertiais proposed here that can operate well with the droop controller, and DC-PSS does notinterfere with power-sharing and does not interact with any of these elements. Since thepresence of a droop controller in HVAC/HVDC grids associates with power and directvoltage, the method proposed here can improve direct voltage fluctuations by eliminatingsevere power peaks. Moreover, this method does not change the voltage level of the entiresystem, so there is no need to change the set-points of controllers. In addition, all param-eters of the controllers are tuned by an intelligent algorithm, and the Participation factor(PF) scheme is used to find the proper placement of the proposed controller