PV, wind and storage integration on small islands for the fulfilment of the 50-50 renewable electricity generation target

Decarbonisation in the generation of electricity is necessary to reduce fossil fuel consumption, the pollution emitted and to meet the Energy Technology Perspectives 2 ¿C Scenario (2DS) targets. Small islands are not exempt from this target, so this study’s emphasis is placed on a 50-50 target: to reduce the fossil fuel consumption through electricity generation from Renewable Energy Sources (RES) to cover 50% of all electric demand by 2050 on small islands. Using Cozumel Island, Mexico, as a case study, this analysis will be based on three factors: economical, technical, and land-use possibilities of integrating Renewable Energy Technologies (RETs) into the existing electrical grid. This analysis is made through long-term statistical models. A deterministic methodology is used to perform time-series simulations. The selection of the best system was made on the basis of a Dimensional Statistical Variable (DSV) through primary and secondary category rankings. The presented methodology determines the best systems for capturing the initial capital cost and competitiveness of this new proposal compared with the current system of electricity generation on the Island, and can be applied to small islands as well. According to the results, all systems proposed are able to completely satisfy the renewable electricity needed by 2050 in all scenarios. From the 12 system proposals that were compared, two systems, System 2 and System 7, were chosen as eligible systems to be installed. The Levelized Cost of Energy (LCOE) result for System 2 was 0.2518 US$/kWh and for System 7 was 0.2265 US$/kWh by 2018 in the Base Scenario. Meanwhile, the Internal Rate of Return (IRR) value fluctuated from 17.2% for System 2 to 31% for System 7.Postprint (published version

Operation and control of a current source converter series tapping of an LCC-HVDC link for integration of offshore wind power plants

This work presents a series tapping station for integrating Offshore Wind Power Plants (OWPP) into a (Line Commutated Converter High Voltage Direct Current) LCC-HVDC transmission system. The tapping station allows to integrate wind power resources without building a new HVDC link and it is based on a Current Source Converter (CSC). However, the CSC requires a minimum DC current to extract the power coming from the OWPP which may not be guaranteed depending on the power conditions of the HVDC corridor. For this reason, this paper proposes a coordinated operation and control of the CSC and the OWPP. A steady-state analysis is performed to determine the appropriate AC voltage level of the CSC. A power reduction algorithm is presented to limit power extraction during a reduction in the current of the HVDC transmission system and under loss of communications between the CSC and the OWPP. The proposed algorithm and the performance of the system are validated through simulation results.Peer ReviewedPostprint (author's final draft

Composed Index for the Evaluation of Energy Security in Power Systems within the Frame of Energy Transitions—The Case of Latin America and the Caribbean

Energy transitions are transforming energy systems around the globe. Such a shift has caused the power system to become a critical piece of infrastructure for the economic development of every nation on the planet. Therefore, guaranteeing its security is crucial, not only for energy purposes but also as a part of a national security strategy. This paper presents a multidimensional index developed to assess energy security of electrical systems in the long term. This tool, named the Power System Security Index (PSIx), which has been previously used for the evaluation of a country in two different time frames, is applied to evaluate the member countries of the Latin American Energy Organization, located within the Latin America and the Caribbean region, to measure its performance on energy security. Mixed results were obtained from the analysis, with clear top performers in the region such as Argentina, while there are others with broad areas of opportunity, as is the case of Hait

Integral approach to energy planning and electric grid assessment in a renewable energy technology integration for a 50/50 target applied to a small island

This paper presents an energy planning, a grid assessment, and an economic analysis, considering three growing scenarios (Low, Base and High) in the electricity consumption, to supply the energy demand for a hybrid power system (Photovoltaics/Wind/Diesel/Battery) on a small island by 2050. The main aim of this study is to present a methodology to optimize and reduce the backup time of the battery bank, included from the hybrid power generation system selected. Also, it will compare four di ff erent battery technologies, simultaneously, without changes in the renewable energy targets settled in 50% until 2050 and without changes in the safe continuous operation of the grid. The methodology includes a grid assessment analysis to obtain a reliable, strong and safe operation response based on the grid code parameters, even in case of disturbance. In the proposed methodology the analysis is developed on the basis of the use of two simulation model tools. The First simulation model tool determines the optimal values of variables that the system designer controls, such as the mix of components (Photovoltaics/Wind/Diesel/Battery) that make up the system and the size or quantity of each variable. This model uses the multiyear analysis based on a time-domain simulation run at the energy- fl ow level with discrete time-steps of 1 h. The Second simulation model tool assumes all the variables and parameters on the grid as constants during the period of the time analyzed. The power fl ow is analyzed through a programming language command script function and re fl ects the system response at a speci fi c time with given speci fi c variables and parameters. The fi nal technical proposal and its fi nancial analysis are obtained applying and validating this methodology on a small island, as well as, the selection of the system to be installed for the renewable electricity generation. The electric grid modi fi cations and reinforcements through the years until 2050, according to the grid code and the renewable energy targets settled for the island ’ s electric power system are included.Postprint (author's final draft

Thermal Modeling of Large Electrolytic Capacitors Using FEM and Considering the Internal Geometry

© 2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting /republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other worksThis article focuses on developing a finite-element method (FEM) model for large capacitors’ thermal modeling and reliability analysis. Thermal modeling for capacitors is critical since the capacitor’s lifetime depends on the capacitor’s maximum temperature. Typically, capacitors have been modeled as a solid element, not considering the capacitor’s internal geometry, leading to temperature estimation errors and requiring extensive testing to adjust the model. The presented methodology to develop the model considers the internal geometry to obtain a reliable model, with sufficient simplicity to adapt the methodology to any electrolytic capacitor. To achieve good results, the capacitor’s winding is modeled as an anisotropic material to reproduce appropriately the behavior of the layers of aluminum and paper soaked in electrolyte. The results of the simulations match the experimental results closely, therefore validating the utility of the model.Peer ReviewedPostprint (published version

Passive and Active Methods of Islanding for PV systems

This paper presents a review of some techniques for islanding detection, especially by using inverter based DG applications and it also focuses on several islanding detection methods for a single- phase current-control voltage inverter working with a PV system connected into the grid. It is deliberated a single-phase inverter with maximum power of 5 kW. Islanding detection methods are investigated, simulated and evaluated in MATLAB / SIMULINK.Peer ReviewedPostprint (author’s final draft

Optimal operation of hybrid high voltage direct current and alternating current networks based on OPF combined with droop voltage control

This study focuses on the operation and control of HVDC multi-terminal systems that transmit the power being generated in offshore wind farms to the terrestrial AC grids. The aim of the paper is to propose and validate an algorithm to ensure optimal operation of HVDC-HVAC systems. This algorithm is implemented in a central controller that, knowing the electrical characteristics of the DC and AC systems, the power generation from the wind farms and the power demand, executes periodically an AC/DC Optimal Power Flow (OPF) and sends the appropriate voltage references to the grid side converter's control. The voltage control of the DC grid is distributed and based on droop law, implemented in grid side converters. The droop offset is modified periodically so as to adapt to the actual operating conditions and ensure optimal operation according to a specified objective function. Dynamic simulations show the system optimal operation in terms of loss minimization under wind speed changes, loss of communications and demand variation. These results are validated experimentally after implementing the control scheme in an HVDC scaled experimental platform. Dynamic simulations are also performed to show that the system can still be operated based on the proposed strategy even during contingencies implying the disconnection of a power system element (converter and DC cable).Postprint (author's final draft

Effect of Current Distortion and Unbalanced Loads on Semiconductors Reliability

This article presents a reliability analysis of a 4-wire grid-tied inverter under different loading conditions, considering unbalanced loads and harmonic distortion in the current consumed. The proposed power converter is used as a case study to assess the impact of current disturbances on the semiconductors’ reliability. The 4-wire inverter analyzed is implemented with a 3-leg SiC MOSFET power module and a neutral wire connected to the midpoint of the DC-link. The analysis is founded on the literature’s reliability curves for power switches. As key take-home findings, the addition of harmonic content in the load current plays a dominant role in the semiconductors’ expected lifetime, especially for the low-frequency harmonics, e.g., third harmonic. Furthermore, the phase delay of the harmonic current content is revealed as a critical factor in the semiconductor’s reliability. Additionally, the existence of unbalanced loads substantially modifies the reliability of the semiconductors of the inverter. The results confirm that converters’ reliability is highly dependent on the loading conditions and harmonic content, so identifying the most critical conditions is inevitable.Peer ReviewedPostprint (published version

Passive and Active Methods of Islanding for PV systems

Abstract This paper presents a review of some techniques for islanding detection, especially by using inverter based DG applications and it also focuses on several islanding detection methods for a single-phase current-control voltage inverter working with a PV system connected into the grid. It is deliberated a single-phase inverter with maximum power of 5 kW. Islanding detection methods are investigated, simulated and evaluated in MATLAB / SIMULINK