1,721,016 research outputs found
A hybrid methodology for the day-ahead PV forecasting exploiting a Clear Sky Model or Artificial Neural Networks
No full textPhotoVoltaic (PV) plants can bring a positive impact on the sustainability of electric grids. Its variability and uncertainty, however, leads to challenging technical problems related to the efficient and secure operations of power systems. In this paper, a novel hybrid methodology for the day-ahead PV power forecasting is proposed. The methodology is able to use a Clear Sky Model (CSM) or an Artificial Neural Network (ANN), according to the day-ahead weather forecasting. Selection among these two methods is performed by a threshold on the Cloud Cover Index (CCI) determined by linear regression. The method has been tested and validated on a real PV plant
A Model Predictive Control-Based Energy Management Strategy for Secure Operations in Shipboard Power Systems
No full textDay-Ahead Programming of Energy Communities Participating in Pay-as-Bid Service Markets
No full textThis paper proposes an optimal strategy for a Renewable Energy Community participating in the Italian pay-as-bid ancillary services market. The community is composed by a group of residential customers sharing a common facility equipped with a photovoltaic power plant and a battery energy storage system. This battery is employed to maximize the community cash flow obtained by the participation in the services market. A scenario-based optimization problem is defined to size the bids to be submitted to the market and to define the corresponding optimal battery energy exchange profile for the day ahead. The proposed optimization scheme is able to take into account the probability of acceptance of the service market bids and the uncertainties in the forecasts of photovoltaic generation and energy demands. Results prove the effectiveness of the approach and the economic advantages of participating in the service market
Performance Investigation of an Optimal Control Strategy for Zero-Emission Operations of Shipboard Microgrids
No full textOne Millinewton FEEP Thruster Tests
No full textThis paper presents the results of functional tests carried out on the first 7 em slit FEEP emitter prototype designed and manufactured at Centrospazio. While FEEP emitters have traditionally been fed with cesium, this thruster used rubidium as a propellant. The investigations carried out include electrical parameters measurement and ion beam profile recording. The use of Rb resulted in immediate, good wetting of the emitter blades and in very good ion emission, while emitter misalignement caused a portion of the usefullenght of the thruster not to operate, showing how sensitive this thruster is to small changes in its delicate geometrical arrangement. Nevertheless, maximum estimated thrust was as high as 1.2 mN and beam divergence was within the expected values
Optimal Storage Allocation for Transmission Network Development Planning: Study Case of Sicily
No full textThe efforts toward a sustainable society require the increasing adoption of Renewable Energy Sources (RESs) at all levels of the power grid. Installation of energy storage systems is a key intervention for managing the new security and environmental needs brought by the RESs volatility. This is especially important for transmission networks prone to congestion issues, with critical links between portions of the grid and with a very high capacity of renewable generation, such as the transmission network of Sicily (Italy). This work uses a probabilistic planning methodology for the optimal allocation and sizing of storage systems, previously developed and applied to a real distribution network, also accounting for reactive regulation of voltage by distributed energy resources. The application is implemented in MATLAB/GAMS environment assuming a new wind offshore farm connected to the reinforced grid according to intervention foreseen by the Italian transmission system operator. The result shows the feasibility of application of the methodology to a transmission network, and can be a robust tool for the allocation and sizing of energy storage systems in the considered scenario
A Security-Constrained Optimal Power Management Algorithm for Shipboard Microgrids with Battery Energy Storage System
No full textThis work proposes an optimal power management strategy for shipboard microgrids equipped with diesel generators and a battery energy storage system. The optimization provides both the unit commitment and the optimal power dispatch of all the resources, in order to ensure reliable power supply at minimum cost and with minimum environmental impact. The optimization is performed solving a mixed integer linear programming problem, where the constraints are defined according to the operational limits of the resources when a contingency occurs. The algorithm is tested on a notional all-electric ship where the ship's electrical load is generated through a Markov chain, modeled on real measurement data. The results show that the proposed power management strategy successfully maximizes fuel saving while ensuring blackout prevention capability
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