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Publicações

Publicações por João Peças Lopes

2016

Experimental validation of smart distribution grids: Development of a microgrid and electric mobility laboratory

Autores
Gouveia, C; Rua, D; Ribeiro, F; Miranda, L; Rodrigues, JM; Moreira, CL; Pecas Lopes, JAP;

Publicação
INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS

Abstract
The development of the Smart Grid concept is the pathway for assuring high reliability, control and management requirements in future electric power distribution systems. The Smart Grid can be defined as an electricity network supported by an intelligent infrastructure, both hardware and software, capable of accommodating high shares of Distributed Energy Resources. Within this line, a Smart Grid laboratorial infrastructure was developed, being dedicated to advanced research and demonstration activities. The adopted laboratorial architecture was developed according to the Microgrid concept, where Electric Vehicles are regarded as active and flexible players. Following the laboratory implementation, this paper provides a detailed description of its infrastructure and experimental capabilities, presenting and discussing different experimental set-ups and associated results.

2015

IMICV fault analysis method with multiple PV grid-connected inverters for distribution systems

Autores
Moura, AP; Lopes, JAP; de Moura, AAF; Sumaili, J; Moreira, CL;

Publicação
ELECTRIC POWER SYSTEMS RESEARCH

Abstract
A novel faults analysis method with multiple PV grid-connected inverters for distribution systems is proposed. The aforesaid proposed method Inverter Matrix Impedance Current Vector (IMICV) employs symmetrical components combined with a matrix denominated of Inverter Matrix Impedance and with a vector denominated Impedance-Current Vector which are formed by inspection. This matrix and this vector are used to solve a linear system of equations where the following post-fault variables are: current in substation, the voltage at the fault point and voltages in the PV grid-connected nodes. A comparison of results obtained using the new method with the results of the professional software ANAFAS validates the method proposed. Computer simulations show that the proposed method for classical shunt faults analysis is efficient, accurate and easy to program.

2015

Microgrids: Enhancing the Resilience of the European Megagrid

Autores
Strbac, G; Hatziargyriou, N; Lopes, JP; Moreira, C; Dimeas, A; Papadaskalopoulos, D;

Publicação
IEEE Power and Energy Magazine - IEEE Power and Energy Mag.

Abstract

2016

Operation scheduling of prosumer with renewable energy sources and storage devices

Autores
Souza, SM; Gil, M; Sumaili, J; Madureira, AG; Pecas Lopes, JAP;

Publicação
2016 13TH INTERNATIONAL CONFERENCE ON THE EUROPEAN ENERGY MARKET (EEM)

Abstract
The reduction or elimination of incentives for the installation of decentralized generation directly at the customers' premises, favoring self-consumption, can bring significant changes for distribution network operation. According to the new Portuguese law, injection of energy into the distribution grid is discouraged since prosumers receive only 90% of the energy cost in the Iberian Energy Market. In order to lower energy bills, the possibility of storing excess energy is being considered as a possible solution. In this paper, an optimization framework is proposed to model the operation of consumers with renewable-based Distributed Generation (DG) and storage capacity and assess their aggregated effect at the level of the MV grid using a multi-temporal Optimal Power Flow (OPF). The proposed algorithm is then tested in a real Portuguese MV network to evaluate its performance. Finally, a financial viability analysis is performed considering the installation of small PV generators and storage devices at the residential level.

2016

Regulatory Issues in the Deployment of Distributed Storage Devices in Distribution Networks

Autores
Ferreira, R; Matos, M; Lopes, JP;

Publicação
2016 13TH INTERNATIONAL CONFERENCE ON THE EUROPEAN ENERGY MARKET (EEM)

Abstract
In this paper, a number of possibilities are presented and discussed for the ownership of distributed storage devices (DSD) in a Smart Grid environment. The cases in which the distribution system operator (DSO) has either full control (grid owned storage) or no control whatsoever over the operation of the DSD (independently owned storage) will be differentiated. For each ownership possibility, the technical and regulatory implications are discussed, with analysis and validation of the results being performed on real MV distribution networks, both rural and urban. In order to evaluate each ownership possibility, a number of multi-period optimization models are presented, corresponding to different assumptions in regards to the operation of the DSD. The resulting daily operation strategies are subsequently used as a basis for carrying out distribution reinforcement planning.

2017

Control of an isolated single-phase bidirectional AC-DC matrix converter for V2G applications

Autores
Varajao, D; Araujo, RE; Miranda, LM; Pecas Lopes, JP; Weise, ND;

Publicação
ELECTRIC POWER SYSTEMS RESEARCH

Abstract
This paper describes a new current control method that enhances the dynamic performance of a singlephase bidirectional AC-DC battery charger to provide a high-frequency link between the grid and electric vehicle. The single-stage structure and the bidirectional power flow make the matrix converter an attractive solution for electric vehicle (EV) battery charging applications in the context of smart grids. The operating principles and modulation method are analyzed and discussed in detail. Furthermore, a current controller improved with a Smith predictor is proposed to decrease the phase delay in the measurement of the average current in the battery pack. The SP reduces the rise time to around a third and the settling time to half when compared with a PI controller. Simulations and experimental results from a laboratory prototype are shown to verify the feasibility of the proposed control scheme.

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