Passivity - Based Control and Stability Analysis for Hydro-Solar Power Systems

Los sistemas de energía modernos se están transformando debido a la inclusión de renovables no convencionales fuentes de energía como la generación eólica y fotovoltaica. A pesar de que estas fuentes de energía son buenas alternativas para el aprovechamiento sostenible de la energía, afectan el funcionamiento y la estabilidad del sistema de energía, debido a su naturaleza inherentemente estocástica y dependencia de las condiciones climáticas. Además, los parques solares y eólicos tienen una capacidad de inercia reducida que debe ser compensada por grandes generadores síncronos en sistemas hidro térmicos convencionales, o por almacenamiento de energía dispositivos. En este contexto, la interacción dinámica entre fuentes convencionales y renovables debe ser estudiado en detalle. Para 2030, el Gobierno de Colombia proyecta que el poder colombiano El sistema integrará en su matriz energética al menos 1,2 GW de generación solar fotovoltaica. Por esta razón, es necesario diseñar controladores robustos que mejoren la estabilidad en los sistemas de energía. Con alta penetración de generación fotovoltaica e hidroeléctrica. Esta disertación estudia nuevas alternativas para mejorar el sistema de potencia de respuesta dinámica durante y después de grandes perturbaciones usando pasividad control basado. Esto se debe a que los componentes del sistema de alimentación son inherentemente pasivos y permiten formulaciones hamiltonianas, explotando así las propiedades de pasividad de sistemas eléctricos. Las principales contribuciones de esta disertación son: una pasividad descentralizada basada control de los sistemas de control de turbinas hidráulicas para sistemas de energía de múltiples máquinas para estabilizar el rotor acelerar y regular el voltaje terminal de cada sistema de control de turbinas hidráulicas en el sistema como, así como un control basado en PI pasividad para las plantas solares fotovoltaicas

Un modelo generalizado y control para almacenadores de energía por superconductor magnético y supercondesador

This paper presents a generalized linear model based on LMI state-feedback with integral action, applicable to the control of Electric Energy Storage Systems (EESS) such as Superconducting Magnetic Energy Storage (SMES) and Supercapacitor Energy Storage (SCES). A Voltage Source Converter (VSC) and a Pulse-Width modulated Current Source Converter (PWM-CSC) are respectively used to integrate the SCES and the SMES systems to the electrical distribution system. To represent the dynamics between the EESS and the power distribution system a reduced general linear model in the state-space representation is introduced. The proposed control scheme regulates independently the active and reactive power ow between the EESS and ac the grid. Three case scenarios comparing a conventional PI controller and the proposed technique are conducted considering grid voltage uctuations. Extensive time-domain simulations demonstrate the robustness and proper performance of the proposed controller to operate the EESS as power compensator, in order to improve the operative conditions of electrical distribution systems.En este articulo se presenta un control de retroalimentación a un modelo lineal generalizado basados en LMI con seguimiento de acción integral para sistemas de almacenamiento de energía eléctrica (SESS) tales como: a almacenamiento de energía magnética por superconducción (SMES) y almacenamiento de energía eléctrica por supercondensador (SCES). Un compacto de modelo lineal general en la representación del espacio de estado para representar el comportamiento dinámico entre el SESS y el sistema de distribución es presentado. Para integrar los sistemas SCES y SMES al sistema de distribución se utilizan un convertidor de fuente de tensión (VSC) y un convertidor de fuente de corriente modulada por ancho de pulso (PWM-CSC), respectivamente. La estrategia de control propuesta permite el control bidireccional de la potencia activa y reactiva entre el EESS y la red ac de manera independiente. Los resultados de las simulaciones demuestran el desempeño robusto y eciente del control propuesto para operar EESS como compensadores de potencia activa y reactiva, con el n de mejorar las condiciones operativas en el sistema de distribución. Además, todos los casos propuestos se compararon con el controlador PI convencional para vericar su validez

Relation between the Branch-to-node Incidence and the Triangular Matrices in Radial Distribution Networks

The power flow solution is a classical problem in electrical engineering that has been studied for more than 60 years [1]. One of the most widely used methods corresponds to the Newton-Raphson approach, which is currently employed for analyzing power systems with meshed configurations and multiple generation sources, i.e., it is typically employed for power systems in high-voltage levels [2].The power flow solution is a classical problem in electrical engineering that has been studied for more than 60 years [1]. One of the most widely used methods corresponds to the Newton-Raphson approach, which is currently employed for analyzing power systems with meshed configurations and multiple generation sources, i.e., it is typically employed for power systems in high-voltage levels [2]

Discrete-Inverse Optimal Control Applied to the Ball and Beam Dynamical System: A Passivity-Based Control Approach

This express brief deals with the problem of the state variables regulation in the ball and beam system by applying the discrete-inverse optimal control approach. The ball and beam system model is defined by a set of four-order nonlinear differential equations that are discretized using the forward difference method. The main advantages of using the discrete-inverse optimal control to regulate state variables in dynamic systems are (i) the control input is an optimal signal as it guarantees the minimum of the Hamiltonian function, (ii) the control signal makes the dynamical system passive, and (iii) the control input ensures asymptotic stability in the sense of Lyapunov. Numerical simulations in the MATLAB environment allow demonstrating the effectiveness and robustness of the studied control design for state variables regulation with a wide gamma of dynamic behaviors as a function of the assigned control gains

On the mathematical modeling for optimal selecting of calibers of conductors in DC radial distribution networks: An MINLP approach

This paper addresses the problem of optimal conductor selection in direct current (DC) distribution networks with radial topology. A nonlinear mixed-integer programming model (MINLP) is developed through a branch-to-node incidence matrix. An important contribution is that the proposed MINLP model integrates a set of constraints related to the telescopic structure of the network, which allows reducing installation costs. The proposed model also includes a time-domain dependency that helps analyze the DC network under different load conditions, including renewable generation and battery energy storage systems, and different voltage regulation operative consigns. The objective function of the proposed model is made up of the total investment in conductors and the total cost of energy losses in one year of operation. These components of the objective function show multi-objective behavior. For this reason, different simulation scenarios are performed to identify their effects on the final grid configuration. An illustrative 10-nodes medium-voltage DC grid with 9 lines is used to carry out all the simulations through the General Algebraic Modeling System known as GAMS

A Possible Classification for Metaheuristic Optimization Algorithms in Engineering and Science

A Possible Classification for Metaheuristic Optimization Algorithms in Engineering and ScienceA Possible Classification for Metaheuristic Optimization Algorithms in Engineering and Scienc

A linearized approach for the electric light commercial vehicle routing problem combined with charging station siting and power distribution network assessment

Transportation electrification has demonstrated a significant position on power utilities and logistic companies, in terms of assets operation and management. Under this context, this paper presents the problem of seeking feasible and good quality routes for electric light commercial vehicles considering battery capacity and charging station siting on the power distribution system. Different transportation patterns for goods delivery are included, such as the capacitated vehicle routing problem and the shortest path problem for the last mile delivery. To solve the problem framed within a mixed integer linear mathematical model, the GAMS software is used and validated on a test instance conformed by a 19-customer transportation network, spatially combined with the IEEE 34 nodes power distribution system. The sensitivity analysis, performed during the computational experiments, show the behavior of the variables involved in the logistics operation, i.e., routing cost for each transport pattern. The trade-off between the battery capacity, the cost of the charging station installation, and energy losses on the power distribution system is also shown, including the energy consumption cost created by the charging operation.Universidad Tecnológica de Bolíva

Optimal Location-Reallocation of Battery Energy Storage Systems in DC Microgrids

This paper deals with the problem of optimal location and reallocation of battery energy storage systems (BESS) in direct current (dc) microgrids with constant power loads. The optimization model that represents this problem is formulated with two objective functions. The first model corresponds to the minimization of the total daily cost of buying energy in the spot market by conventional generators and the second to the minimization of the costs of the daily energy losses in all branches of the network. Both the models are constrained by classical nonlinear power flow equations, distributed generation capabilities, and voltage regulation, among others. These formulations generate a nonlinear mixed-integer programming (MINLP) model that requires special methods to be solved. A dc microgrid composed of 21-nodes with existing BESS is used for validating the proposed mathematical formula. This system allows to identify the optimal location or reallocation points for these batteries by improving the daily operative costs regarding the base cases. All the simulations are conducted via the general algebraic modeling system, widely known as the General Algebraic Modeling System (GAMS)

Optimal selection and location of bess systems in medium-voltage rural distribution networks for minimizing greenhouse gas emissions

This paper explores a methodology to locate battery energy storage systems (BESS) in rural alternating current (AC) distribution networks fed by diesel generators to minimize total greenhouse gas emissions. A mixed-integer nonlinear programming (MINLP) model is formulated to represent the problem of greenhouse gas emissions minimization, considering power balance and devices capabilities as constraints. To model the BESS systems, a linear relationship is considered between the state of charge and the power injection/consumption using a charging/discharging coefficient. The solution of the MINLP model is reached through the general algebraic modeling system by employing the BONMIN solver. Numerical results in a medium-voltage AC distribution network composed of 33 nodes and 32 branches operated with 12.66 kV demonstrate the effectiveness of including BESS systems to minimize greenhouse gas emissions in diesel generators that feeds rural distribution networks

Minimización exacta de las pérdidas de energía y las emisiones de CO2 en redes de distribución DC aisladas empleando fuentes fotovoltaicas

This paper addresses the optimal location and sizing of photovoltaic (PV) sources in isolated direct current (DC) electrical networks, considering time-varying load and renewable generation curves. The mathematical formulation of this problem corresponds to mixed-integer nonlinear programming (MINLP), which is reformulated via mixed-integer convex optimization: This ensures the global optimum solving the resulting optimization model via branch & bound and interior-point methods. The main idea of including PV sources in the DC grid is to minimize the daily energy losses and greenhouse emissions produced by diesel generators in isolated areas. The GAMS package is employed to solve the MINLP model, using mixed and integer variables; also, the CVX and MOSEK solvers are used to obtain solutions from the proposed mixed-integer convex model in the MATLAB. Numerical results demonstrate important reductions in the daily energy losses and the harmful gas emissions when PV sources are optimally integrated into DC grid.Este paper aborda la ubicación y el tamaño óptimos de las fuentes fotovoltaicas (PV) en redes eléctricas aisladas de corriente continua (CC), considerando la carga variable en el tiempo y las curvas de generación renovable. La formulación matemática de este problema corresponde a la programación no lineal de enteros mixtos (MINLP), que es reformulada mediante optimización convexa de enteros mixtos. Esto asegura el óptimo global resolviendo el modelo de optimización resultante a través de métodos de punto interior y ramificación. La idea principal de incluir fuentes fotovoltaicas en la red de CC es minimizar las pérdidas diarias de energía y las emisiones de efecto invernadero producidas por los generadores diésel en áreas aisladas. El paquete GAMS se emplea para resolver el modelo MINLP, utilizando variables mixtas y enteras. Además, los solucionadores CVX y MOSEK se utilizan para obtener soluciones del modelo convexo de enteros mixtos propuesto en MATLAB. Los resultados numéricos demuestran importantes reducciones en las pérdidas diarias de energía y las emisiones de gases nocivos cuando las fuentes fotovoltaicas se integran de manera óptima en la red de CC