Browsing by Author "1103"
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    Control Room Requirements for Voltage Control in Future Power Systems
    ( 2018) Filipe Joel Soares ; João Peças Lopes ; Riano,S ; Merino,J ; Coelho,A ; 4999 ; 1103
    In future power grids, a large integration of renewable energy sources is foreseen, which will impose serious technical challenges to system operators. To mitigate some of the problems that renewable energy sources may bring, new voltage and frequency control strategies must be developed. Given the expected evolution of technologies and information systems, these new strategies will benefit from increasing system observability and resources controllability, enabling a more efficient grid operation. The ELECTRA IRP project addressed the new challenges that future power systems will face and developed new grid management and control functionalities to overcome the identified problems. This work, implemented in the framework of ELECTRA, presents an innovative functionality for the control room of the cell operator and its application in assistance with the voltage control designed for the Web-of-Cells. The voltage control method developed uses a proactive mode to calculate the set-points to be sent to the flexible resources, each minute, for a following 15-min period. This way, the voltage control method developed is able to mitigate voltage problems that may occur, while, at the same time, contributes to reduce the energy losses. To enable a straightforward utilization of this functionality, a user interface was created for system operators so they can observe the network state and control resources in a forthright manner accordingly.
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    Dimensioning Studies for Reversible Hydro Power Plants in Portuguese Islands
    ( 2018) Manuel Matos ; Nuno Soares Fonseca ; André Guimarães Madureira ; João Peças Lopes ; 1103 ; 214 ; 5517 ; 4560
    This work is within the scope of set of consultancy studies made for Portuguese islands. It focuses on the integration of Pumped Storage Power in isolated islands. The paper starts to address several power systems circumstances about two Portuguese islands on the energetic level. For each of these islands, an independent examination of the conditions to install a reversible hydro power plant is accomplished. Therefore, the energy volume to be stored due to excess of renewable generation and the ideal power and number of the pumps and turbines to be installed were identified and evaluated for the sake of using the produced energy surplus as to be pumped and later generated. The paper enhances the importance of storing energy in the operation of isolated and small systems with considerable amount of intermittent power resources as well as the conditions for the viability of installing new exploitations of this kind.
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    Dynamic security of islanded power systems with pumped storage power plants for high renewable integration – A study case
    ( 2019) Helena Vasconcelos ; Beires,P ; Carlos Moreira ; João Peças Lopes ; 1103 ; 3348 ; 4442
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    Electric Vehicles Charging: Management and Control Strategies
    ( 2018) Bruna Costa Tavares ; João Peças Lopes ; Coelho,AM ; Filipe Joel Soares ; David Emanuel Rua ; Clara Sofia Gouveia ; 5524 ; 5226 ; 4999 ; 1103 ; 6593
    In this article, we present a holistic framework for the integration of electric vehicles (EVs) in electric power systems. Their charging management and control methodologies must be optimized to minimize the negative impact of the charging process on the grid and maximize the benefits that charging controllability may bring to their owners, energy retailers, and system operators. We have assessed the performance of these methods initially through steady-state computational simulations, and then we validated them in a microgrid (MG) laboratory environment. © 2018 IEEE.
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    Operation of multi-microgrids
    ( 2013) André Guimarães Madureira ; Fernanda Resende ; Gil,N ; João Peças Lopes ; 4643 ; 4560 ; 1103
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    Stability of autonomous power systems with reversible hydro power plants: A study case for large scale renewables integration
    ( 2018) Pedro Portela Beires ; João Peças Lopes ; Carlos Moreira ; Helena Vasconcelos ; 4442 ; 1103 ; 3348 ; 6829
    This paper addresses the dynamic stability analysis of an islanded power system regarding the installation of a reversible hydro power plant for increasing renewable energy integration. Being a high-head facility, the hydro power plant consists of separated pumps and turbines (Pelton type). In order to properly support the identification of hydro pumps connection requirements and the technology to be used, different options were taken into consideration, namely: fixed speed pumps coupled to induction machines directly connected to the grid and adjustable speed pumps supplied by a drive system. Extensive numerical simulations of the power system's dynamic behaviour response allowed the evaluation of the hydro power plant's role for the purpose of grid stability conditions. These simulations showed that the high-head hydro power installation provides a marginal contribution to system frequency regulation when explored in turbine operation mode, leading to a reversible power station with a single penstock. Moreover, due to the significant additional system load introduced by the hydro pumping units, the obtained results clearly indicate that supplementary regulation flexibility is required to attend the need of assuring the stable operation of the system in case of critical disturbances such as grid faults. The study case demonstrates that, although the foreseen operation of a reversible hydro power plant creates new security challenges to overcome in an autonomous power system, robust technical solutions can be identified without increasing, from the local system operator's perspective, the operation complexity of the power system. © 2018 Elsevier B.V.