2022
Authors
Lotfi, M; Osorio, GJ; Javadi, MS; El Moursi, MS; Monteiro, C; Catalao, JPS;
Publication
INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS
Abstract
Traditional power grids, being highly centralized in terms of generation, economy, and operation, continually employed probabilistic methods to account for load uncertainties. In modern smart grids (SG), rapid proliferation of non-dispatchable generation (physical decentralization) and liberal markets (market decentralization) leads to dismantling of the centralized paradigm, with operation being performed by several decentralized agents. Handling uncertainty in this new paradigm is aggravated due to 1) a vastly increased number of uncertainty sources, and 2) decentralized agents only having access to local data and limited information on other parts of the grid. A major problem identified in modern and future SGs is the need for fully decentralized optimal operation techniques that are computationally efficient, highly accurate, and do not jeopardize data privacy and security of individual agents. Machine learning (ML) techniques, being successors to traditional probabilistic methods are identified as a solution to this problem. In this paper, a conceptual model is constructed for the transition from a fully centralized operation of a SG to a decentralized one, proposing the transition scheme between the two paradigms. A novel ML algorithm for fully decentralized operation is proposed, formulated, implemented, and tested. The proposed algorithm relies solely on local historical data for local agents to accurately predict their optimal control actions without knowledge of the physical system model or access to historical data of other agents. The capability of cloud-based cooperative information exchange was augmented through a new concept of s-index activation codes, being encoded vectors shared between agents to improve their operation without sharing raw information. The algorithm is tested on a modified IEEE 24-bus test system and synthetically generating historical data based on typical load profiles. A week-ahead high-resolution (15 minute) fully decentralized operation case is tested. The algorithm is shown to guarantee less than 0.1% error compared to a centralized solution and to outperform a neural network (NN). The algorithm is exceptionally accurate while being highly computationally efficient and has great potential as a versatile model for fully decentralized operation of SGs.
2022
Authors
Lotfi, M; Almeida, T; Javadi, MS; Osorio, GJ; Monteiro, C; Catalao, JPS;
Publication
APPLIED ENERGY
Abstract
The rapid proliferation of Electric Vehicles (EVs) creates an inherent link between the previously independent transport and power sectors. This is especially relevant in the smart cities paradigm, which focuses on optimizing resource management using modern software tools and communication infrastructures. The optimal management of energy resources is of key importance, and with mobile EVs playing a pivotal role in smart city power flows, the coordination of energy management systems (EMSs) at their parking locations can bear global benefits. In this study the coordination between home energy management systems (HEMSs) and EV parking lot management systems (PLEMS) is proposed, modeled, and simulated, as a new contribution to earlier studies. The EMSs coordinate through partially sharing individual EV schedules and without sharing private information. Missing information is completed through public cloud repositories and services. The HEMS and PLEMS are implemented using mixed-integer linear programming (MILP). The proposed coordination framework is computationally implemented and simulated based on a real-life case study. The results show that the proposed EMS coordination framework is both technically beneficial for power grids and economically beneficial for EV owners.
2012
Authors
Lujano Rojas, JM; Monteiro, C; Dufo Lopez, R; Bernal Agustin, JL;
Publication
ENERGY POLICY
Abstract
This paper presents an optimal load management strategy for residential consumers that utilizes the communication infrastructure of the future smart grid. The strategy considers predictions of electricity prices, energy demand, renewable power production, and power-purchase of energy of the consumer in determining the optimal relationship between hourly electricity prices and the use of different household appliances and electric vehicles in a typical smart house. The proposed strategy is illustrated using two study cases corresponding to a house located in Zaragoza (Spain) for a typical day in summer. Results show that the proposed model allows users to control their diary energy consumption and adapt their electricity bills to their actual economical situation.
2011
Authors
Ramirez Rosado, IJ; Alfredo Fernandez Jimenez, LA; Monteiro, C; Garcia Garrido, E; Zorzano Santamaria, P;
Publication
RENEWABLE ENERGY
Abstract
This paper presents an original forecasting methodology for achieving the spatiotemporal future long-term expansion of small power photovoltaic (PV) systems in a region, taking into account the population density, ground usage and the type of small PV power application adopted. This methodology comprises three stages: a first stage based on a suitable PV technological forecasting method with a group of experts; a second stage consisting of an innovative and iterative process based on elimination of the possible numerical inconsistencies achieved in the first stage; a third stage with a new method for achieving PV power density maps, using a geographical information system (GIS), that provides significant quantitative GIS information and visual and geographically-disaggregated representation of future small power PV systems expansion. The proposed methodology is illustrated with a real example for the region of La Rioja, Spain. In this example, four different combinations of PV systems and geographical zones were considered, and they are referred to as four "PV technologies" in the paper. The forecasted period range was 20 years with steps of 5 years. The results offer very valuable information for electric utilities, PV systems sales and installation agents, investors and regional authorities responsible for energy plans.
2012
Authors
Lujano Rojas, JM; Monteiro, C; Dufo Lopez, R; Bernal Agustin, JL;
Publication
RENEWABLE ENERGY
Abstract
This paper discusses a novel load management strategy for the optimal use of renewable energy in systems with wind turbines, a battery bank, and a diesel generator. Using predictions concerning wind speed and power, controllable loads are used to minimize the energy supplied by the diesel generator and battery bank, subject to constraints imposed by the user's behavior and duty cycle of the appliances. We analyzed a small hybrid power system in Zaragoza, Spain, and the results showed load management strategy allowed improvement in the wind power use by shifting controllable loads to wind power peaks, increasing the state of the charge in the battery bank, and reducing the diesel generator operating time, when compared to a case without load management.
2009
Authors
Ramirez Rosado, IJ; Alfredo Fernandez Jimenez, LA; Monteiro, C; Sousa, J; Bessa, R;
Publication
RENEWABLE ENERGY
Abstract
This paper presents a comparison of two new advanced statistical short-term wind-power forecasting systems developed by two independent research teams. The input variables used in both systems were the same: forecasted meteorological variable values obtained from a numerical weather prediction model: and electric power-generation registers from the SCADA system of the wind farm. Both systems are described in detail and the forecasting results compared, revealing great similarities, although the proposed structures of the two systems are different. The forecast horizon for both systems is 72 h, allowing the use of the forecasted values in electric market operations, as diary and intra-diary power generation bid offers, and in wind-farm maintenance planning.
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