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Publications

Publications by CPES

2024

Holistic regulatory framework for distributed generation based on multi-objective optimization

Authors
da Costa, VBF; Bitencourt, L; Peters, P; Dias, BH; Soares, T; Silva, BMA; Bonatto, BD;

Publication
JOURNAL OF CLEANER PRODUCTION

Abstract
Regulatory changes associated with distributed generation have occurred in several countries (e.g., the USA, Germany, the UK, and Australia). However, there is a lack of robust and holistic analytical models that can be used to implement the best regulatory framework among possible options. In this context, the present paper proposes a cutting-edge regulatory framework for distributed generation based on multi-objective optimization, taking into account socioeconomic (socioeconomic welfare created by the regulated electricity market and electricity tariff affordability) and environmental (global warming potential) indicators. Such indicators are modeled primarily based on the optimized tariff model (socioeconomic regulated electricity market model), Bass diffusion model (forecasting model of distributed generation deployment), and life cycle assessment (environmental impact assessment method). The design variables are assumed to be the regulated electricity tariff and remuneration of the electricity injected into the grid over the years. First, the proposed methodology is applied to fifteen large-scale Brazilian concession areas with a significant deployment of distributed generation assuming two approaches, a multi-compensation scenario, where the compensation is set individually for each concession area, and a single-compensation scenario, where the compensation is set equally for all concession areas. Then, the optimal solutions are compared to Ordinary Law 14300, which is a recently implemented regulatory framework for distributed generation in Brazil. Results demonstrate that Ordinary Law 14300 is a dominated or non-optimal solution since it is not located on the optimal Pareto frontiers for any of the assessed concession areas. Assuming the Euclidian knee points, benefits averaging 33% and 15% were achieved in terms of electricity tariff affordability for the multi and single-compensation scenarios, respectively, with small losses of 8% and 3% in terms of socioeconomic welfare and global warming potential. Though the proposed methodology is applied in the Brazilian context, it can also be applied to other countries with regulated electricity markets; thus, it is expected to be valuable for researchers, government institutions, and regulatory agencies worldwide.

2024

A dynamic reference voltage adjustment strategy for Open-UPQC to increase hosting capacity of electrical distribution networks

Authors
Kazemi-Robati, E; Hafezi, H; Faranda, R; Silva, B; Nasiri, MS;

Publication
SUSTAINABLE ENERGY GRIDS & NETWORKS

Abstract
Future electrical grids, particularly the distribution networks, may face more severe voltage rises/drops, and in general, more power quality problems in the presence of new loads such as electric vehicle chargers and renewable energy generation units like photovoltaic systems. This necessitates investing in additional high-cost infrastructure to increase the capability of the feeder in hosting higher levels of loads and generation units while the existing capacity is not utilized effectively. In the stated condition, effective voltage stabilization strategies in electrical distribution networks can contribute to hosting capacity improvement and the better utilization of the existing infrastructure. Accordingly, in this paper, the application of Open-UPQC in voltage profile improvement and hosting capacity enhancement is evaluated in low-voltage distribution networks. Furthermore, a dynamic reference voltage adjustment strategy is applied to the device to improve its capabilities in power quality improvement and hosting capacity enhancement. Simulation studies have been implemented to evaluate the capability of Open-UPQC either with static reference voltage or the dynamically-adjusted one in low-voltage networks with real measured data while different cases are assessed regarding the topology and the length of the feeder. The simulation results approved the capability of Open-UPQC especially with the dynamic reference voltage in hosting capacity enhancement while providing the highest level of voltage profile improvement among all the assessed custom power devices in the studied low-voltage networks.

2024

Optimal Sizing and Energy Management of Battery Energy Storage Systems for Hybrid Offshore Farms

Authors
Varotto, S; Trovato, V; Kazemi Robati, E; Silva, B;

Publication
2024 IEEE 22nd Mediterranean Electrotechnical Conference, MELECON 2024

Abstract
This paper investigates the financial benefits stemming from the potential installation of battery energy storage systems behind the meter of a hybrid offshore farm including wind turbines and floating photovoltaic panels. The optimal investment and operation decisions concerning the energy storage system in the hybrid site are assessed by means of a mixed integer linear programming optimization model. The operation is also subject to technical constraints such as limitations on the connection capacity and ramping constraints imposed by the grid operator at the point of common coupling. Three design configurations for the battery system are analysed: I) offshore with the hybrid farm, II) onshore where the grid connection point is, III) both offshore and onshore. The results indicate the financial value of installing battery storage units, and other benefits deriving from this investment, as the reduction of curtailment. © 2024 IEEE.

2024

A Two-Phase Approach for the Electrical Layout Optimization of the Offshore Wind Farms

Authors
Castro, RM; Silva, B; Kazemi Robati, E;

Publication
2024 IEEE 22nd Mediterranean Electrotechnical Conference, MELECON 2024

Abstract
Due to the current focus on offshore renewable energies worldwide, more capacity of them is expected in the future. The electrical layout design considerably affects overall implementation cost of these offshore power plants as well as the losses of energy inside the farms. Considering the increasing size of offshore wind farms, it is necessary to develop more robust and computationally efficient methods to design the electrical layout of these farms. In this work, a two-phase approach is proposed for the optimization of the electrical layout of the offshore wind farms; the proposed framework aims at the minimization of the ohmic losses and the cost of the cables. To solve the optimization problem, Simulated Annealing (SA) is applied in this study. A tool is also developed using Python programming language to implement the framework for the optimization of the electrical layout of the offshore farms. The proposed method is then applied to a farm with 100 turbines and an overall rated capacity of 1GW. The results approved the accuracy of the two-phase approach in finding the optimal electrical layout as well as the high efficiency in terms of the computational burden. © 2024 IEEE.

2024

Offshore Wind Farm Black Start With Grid-Forming Control

Authors
Prakash, PH; Peças Lopes, J; Silva, B;

Publication
2024 IEEE 22nd Mediterranean Electrotechnical Conference, MELECON 2024

Abstract
This paper introduces a detailed procedure for executing a black start service from an offshore wind farm (OWF) through the integration of grid-forming (GFM) control. The proposed strategy involves exploiting a grid-forming battery energy storage system (BESS) to deliver black start service within an OWF equipped with grid-following wind turbines. Controller modelling, and operation methodology are explained. To illustrate the efficacy of the suggested control and operation principles, the study employs an OWF as a case study. Simulation analyses are conducted using the Matlab/Simulink software to demonstrate the viability of the presented strategy. © 2024 IEEE.

2024

Black Start of an Off-grid Offshore Wind Farm with Grid Forming Converter

Authors
Prakash, H; Lopes, P; Silva, B;

Publication
IET Conference Proceedings

Abstract
This paper presents a comprehensive procedure for conducting a black start service from an offshore wind farm (OWF) by integrating grid-forming (GFM) control. The proposed strategy utilizes a grid-forming battery energy storage system (BESS) to provide black start service within an OWF that is equipped with grid-following wind turbines. The paper elaborates on the modeling of controllers and the operational methodology taking wind variability during the black start procedure. To showcase the effectiveness of the proposed control and operation principles, the study utilizes an OWF as a case study. Simulation analyses are performed using Matlab/Simulink software to validate the feasibility of the proposed strategy. © Energynautics GmbH.

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