Planificación de los sistemas de distribución incluyendo a vehículos eléctricos con métodos heurísticos

Memoria para optar al título de Ingeniero Civil EléctricoEl calentamiento global y sus consecuencias hacen cada vez más urgente reducir las emisiones de carbono. Chile se comprometió a modificar su matriz energética a mediano plazo. En este contexto, la electro-movilidad parece un camino interesante para el sector del transporte. Además, las proyecciones de precios de las tecnologías asociadas hacen económicamente viable esta opción en menos de 10 años. Sin embargo, su desempeño tendrá un impacto sobre la red de distribución y así la tarifa asociada. Este trabajo tiene por objetivo evaluar esta potencial alza de tarifa. El negocio de la distribución es un monopolio geográfico y por lo tanto el precio al usuario se fija por la entidad regulatoria. En Chile, la tarifa se calcula cada cuatro años a través del estudio de Valor Agregado a la Distribución. Este considera comparar la distribuidora a una empresa modelo creada desde cero. Por eso, esta memoria presenta una metodología para generar la red óptima que conecta a los clientes con la subestación. Evaluar el costo de dicha red por distintos niveles de incorporación de vehículos eléctricos permite obtener una aproximación de la posible alza de tarifa. El procedimiento propuesto e implementado es un heurístico en 5 etapas. Primero, se determina el trazado óptimo sobre la red de calle. Segundo, se busca minimizar el sistema primario porque este es el más caro. Tercero, se minimiza el número de transformadores para aprovechar las economías de escala. Cuarto, se busca la ubicación ideal de los transformadores para reducir el tamaño de los conductores de baja tensión. Finalmente, se asegura que el trazado de las redes de baja tensión sea optimizado. Si bien esta optimización heurística local no garantiza el óptimo global, genera resultados correctos con esfuerzos computacionales razonables. Esta metodología fue aplicada en la zona de La Florida en Chile. El área estudiada se expande sobre 127 km2 e incluye 396.638 clientes. Se determinó un incremento de 4% en el costo del sistema por cada franja de 25% de penetración de vehículos eléctricos. En particular, es importante destacar que si todos los hogares se equipan de un auto eléctrico, el costo solo sube de 16% mientras que la demanda se duplica. Además, comparar este aumento con los beneficios en términos de emisiones de carbono ahorradas, se puede afirmar que la integración de vehículos eléctricos es conveniente para la sociedad. Sin embargo, se debe complementar este resultado con un estudio de los potenciales impactos de la electro-movilidad sobre los sectores de la transmisión y de la generación.FONDECYT N°1118087

Non-linear interaction between a synchronous generator and grid-forming-controlled wind turbines – inertial effect enhancement and oscillation mitigation

The integration of grid-forming (GFM)-controlled wind turbines into AC grids introduces complex dynamic interactions that significantly influence the behavior on the AC side. This study explores the non-linear coupling between wind turbines and AC grids and proposes strategies for the enhancement of the inertial effect and the mitigation of oscillations which can arise in case of an AC event such as a grid fault or sudden load change. A simplified synthetic model is developed to elucidate the physical insights of these interactions. The findings reveal that wind turbine dynamics have an impact on the inertial contribution and introduce oscillatory behavior under certain conditions. Advanced control strategies are then proposed. They include the integration of input-shaping filters and lead–lag compensation to optimize inertial response and damp mechanical oscillations. The theoretical analysis, validated through simulation, demonstrates the effectiveness and limitations of these methods in enhancing the AC side behavior without compromising the performance of the mechanical system.</p

Small signal analysis of DC voltage control based on a virtual resistance of DC/DC converter integrated in a multiterminal DC grid

AbstractThe future multi‐terminal direct‐current (MTDC) grid will require the interconnection of point‐to‐point high‐voltage (HV) DC links with different specifications such as DC voltage level, system grounding configuration and HVDC technology. To adapt these differences, it is obligatory for DC/DC converters to interconnect HVDC links. Additionally, they are capable of providing supplementary functionalities as they are highly controllable devices. In this article, a primary virtual resistance DC voltage controller associated with DC/DC converter is proposed for managing DC grid voltages of the interconnected HVDC grids, increasing the reliability of the system. The commonly known topology, Front‐to‐Front Modular Multilevel Converter (F2F‐MMC) is adopted for DC/DC converter. Time‐domain simulations are performed using EMTP software for validating the controller behaviour under power disturbances and large events of loss of one converter in a MMC‐based MTDC system. The converters are modelled using reduced order modelling (ROM) methodology. Apart from this, dynamic studies have been carried out using a linear state space model for small‐signal stability analysis of a HVDC system integrating DC/DC converter with a virtual resistance DC voltage controller. The results are examined through parametric sensitivity analysis

Reduce Order Modeling of the modular multilevel DC/DC converter (M2DC) for HVDC grid

The Modular Multi-Level DC-DC Converter (M2DC) is an attractive non-isolated DC-DC converter topology for HVDC grid. In order to carry out MTDC grid stability studies, the development of reduce order models of converters is necessary. This article first presents the M2DC converter. Then, the reduce order model will be developed in the second part. The development of the control of this model will be carried out in the third part. Atlast, the comparison of the reduce order model and its control with the average arm model will be performed in the later section of the paper

COMPARISON OF THE RADIO-ISOTOPIC COMPOSITION BETWEEN HOT SPRING WATER OF HAMMAM DEBAGH AND ITS ASSOCIATED DEPOSITS

Abstract A radiological analysis of hot spring water of Hammam Debagh (also called Hammam Meskhoutine) and its associated deposits was realized. Hammam Debagh is considered to be the second hottest springs in the world with a temperature of 98°C and this lead to the creation of travertine. This later was formed because of limestone deposited by mineral springs in a rapid sedimentation of calcium, magnesium bicarbonates, and sulphides. The analysis showed that two-thirds of radioactivity was left by spring water in their deposits. The presence of uranium in the spring deposits was due to the property of the uranyl ion to form stable complexes with carbonates and precipitates. The radiation hazards indexes were estimated and compared with those given in literature.</jats:p

Impact of Grid-forming Converter on Electromechanical Oscillations

As distributed generation increases, it is essential to study its impact on the grid dynamics. This paper focuses on understanding the influence of the emergent technology of Grid-Forming converters on the electromechanical oscillations of the power system. Interactions among synchronous generators and gridforming converters are analyzed thanks to simplified models. These highlight the similarities of both sources, and thus, explain the participation of the converter in the oscillation. They also revealed the differences that justify the damping effect of Grid-Forming converter. This conclusion, obtained with simplified models, is validated with a small-signal stability analysis of a detailed model in the dq0-frame

Modular Multilevel DC Converter : Impact of the Control on the Design and Efficiency

The Modular Multilevel DC Converter is an attractive non-isolated topology to inter- connect High Voltage DC Links. This paper presents the interaction among control, component design and efficiency of this converter. The impact of the two degrees of freedom on the design and the efficiency is analyzed