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One-level optimization methods have been proposed to optimize a single user’s load profile or a cluster of users in the smart grids. In this work, two two-level optimization methods are studied, one case considering technical requirements (case 1) and another considering economic criterion (case 2). In the upper level, the supplier optimizes the objective function. Meanwhile, at the lower level, users optimize their electrical costs. The proposed methods are based on Genetic Algorithm methods. In this sense, an indirect control is established in which users react to a price signal. Simulation results illustrate that both cases improve the demand profile and increase the retailer profit concerning an unscheduled case. However, when the supplier tries to maximize the profit, some users receive benefits to detriment of others, concluding that the technical approach is preferable to the economic one.

The integration of Distributed Energy Resources (DER) implies an important challenge for the protection of the distribution network, due to the incorporation of devices with less capacity to withstand normal disturbances in distribution systems, particularly for overcurrents and overvoltages. The increasingly widespread use of power electronics, incorporated in rectifiers and inverters, which due to its weakness requires highspeed protection devices, complicates coordination with the traditional protection of distribution systems. Converters (rectifiers and inverters) require ultra-fast protection against high current faults, conditions that currently only meet high breaking capacity fuses. The response characteristics of these ultra-fast fuses, oblige the professional in charge of the protection of the distribution system to have a deep knowledge about the behavior of the power electronics in the face of overcurrents, and to know also how the fuses, through the selection of its rated values and characteristic curves protects it. Coordination of the rating values and characteristics of these fuses with their counterparts (when they exist) of traditional protection devices is the main objective of this article. Particular terms are explained in detail, such as fault current asymmetry and its effect on the coordination of protections, specific energy, etc. It is concluded that deep knowledge of the dissimilar characteristics of power electronics devices and the usual devices of distribution networks, with regard to their protections, are essential to obtain a maximum use of the traditional scheme with the addition of DER.

One-level optimization methods have been proposed to optimize the load profile of a single user or a cluster of users in the smart grids. In this work, two two-level optimization methods are studied, one considering technical requirements and other considering economic criteria. In the upper level, the supplier optimizes it objective function. Meanwhile, at the lower level, users optimize their electrical costs. The proposed methods are based on genetic algorithm methods. In this sense, an indirect control is established in which users react to a price signal. Simulations results illustrate that both cases improve the demand profile and increase the retailer profit. However, when the supplier tries to maximize the profit, some users receive benefits in detriment of others, concluding that the technical approach is preferable than the economical one.

espanolEl objetivo de este articulo es desarrollar el concepto de gestion de la demanda en relacion a los tipos de control existentes y presentar un ejemplo simple de optimizacion de la demanda para evaluar las potencialidades de un control hibrido. Se presenta una breve introduccion, detallando el conocimiento actual en gestion de demanda, se desarrolla el concepto de control directo e indirecto sobre la demanda, se identifica, y se elabora una tabla con las cargas residenciales. Se modelan dos residencias que podran modificar su carga ante un esquema de precios dados y un objetivo de no concentracion de la demanda fijados por la distribuidora, obteniendo una correcta optimizacion y dispersando las cargas de diferente forma en la segunda ronda. Se concluye que una intervencion de la distribuidora puede mejorar la distribucion de la demanda por la aleatoriedad del algoritmo genetico sin comprometer la privacidad del usuario. EnglishThe article aims is to develop the demand side management concept in relation to existing control types. It also aims to providing a simple example of demand optimization to evaluate the potentialities of a hybrid control. A brief introduction is presented detailing the state of the art. Then, the direct and indirect control over demand was discussed, the types of loads were described, and a table with the residential loads was prepared. Two residences were modeled, which could modify their load before a given price scheme and a nonconcentration objective set by the distributor. This resulted in obtaining a correct optimization and distributing of the loads in a different way in the second round. It is concluded that an intervention of the distributor can improve the distribution of the demand by the randomness of the genetic algorithm without compromising user privacy.

In this work the implementation of dynamic programming is studied as control logic of the power quality in medium voltage electric distribution systems with distributed generation. This was done with the aim of optimizing the power quality indicators and the operation costs; and also to improve the energy efficiency, as well as to take advantage of the transport capacity and of the distribution of the network. With this purpose the work was carried out on a real distribution system belonging to the EPEC company of the Cordoba province in Argentina. The real system behavior was modeled by means of the software ATP/EMTP. Afterwards, a platform was built for the control using MATLAB and an algorithm was developed to process the information and to adjust the system under the new operation conditions. The results indicate that it is possible to control, to regulate and to improve quality indicators, optimizing the distributed generation entrance.

The following paper presents the design of a set of rules which allow the implementation of an expert system. It is intended to manage Automatic Disconnection and Generation Reduction (D-RAG) in a way such that the control logic does not depend on the topology of the network and that in turn does not require a large number of simulations for its implementation. From the definition of a series of factors referring to lines and generators, a set of rules of operation are formulated that define the behavior of the proposed Expert System. The logic was applied to a library case (IEEE 39 bars New-England Power System), verifying the results obtained by simulation using a commercial package of widespread use, Power System Simulator for Engineering. In this way the control logic is determined by the data structure and the set of rules based on theoretical concepts, this demonstrates the flexibility of the proposed solution.

Este trabajo presenta un estudio y análisis detallado de la importancia e implicancia de la regulación del desbalance, por la inserción de la generación distribuida, en una red de distribución de electricidad en el nivel de media tensión. El desbalance constituye un problema de eficiencia energética en los sistemas eléctricos de potencia ya que produce demandas y pérdidas de energía adicionales. Para este estudio, se trabajó sobre un sistema real de distribución de la empresa EPEC de la provincia de Córdoba en Argentina, modelando el comportamiento real del mismo mediante el software ATP/EMTP. Los resultados muestran que el efecto que produce la generación distribuida es positivo, en cuanto a disminuir el desbalance en la red. El coeficiente de desclasificación obtenido es un buen indicador del comportamiento energético. Se concluye que es posible regular y disminuir el desbalance con la inserción de la generación distribuida.

The present energy crisis drives to carry to an extreme the use of all the available energy sources, which need to be connected in their closest point. Traditional electric systems are changing their characteristics. Power quality is one of the aspects modified by the presence of distributed generation (DG), specially respect to harmonics, flicker, voltage sags and overvoltages. The new protection problems of the different parts of the system are explained. The contribution of generators to short circuit currents is analyzed. Philosophy changes are studied, such as: fault current bi-directionality, modification of the protection reach, failures of the overcurrent coordination, etc. It is analyzed the impact of the "islanding operation". It is concluded that DG application offers technical-economic advantages so much to the utility as to the user.

This paper is divided into two parts, the first presents the modeling and simulation of a wind generator connected to the power grid, is covered in detail each component of the wind farm. For the simulation package is used Alternative Transients Program (ATP) showing the versatility of this model to incorporate non-existent models. All parameters respond to simulated models of commercial properties and specifications provided by power system operators. Shows in detail the implementation of the wind turbine by using the simulation language MODELS ATP itself. The paper concludes with a simulated wind contingency showing the response of the entire chain. The ATP package is shown capable of simulating the studies requested by the Compania Administradora del Mercado Mayorista Electrico (CAMMESA). The second part deals with two basic studies related to wind power, capacitive compensation and blade control.

En este trabajo se presenta el diseño de un controlador experto para el nivel de voltaje en un sistema eléctrico de potencia. La utilización del concepto de nodo piloto permite mantener la lista de controladores estable ante los cambios topológicos de la red. La normativa del Operador Eléctrico de la Provincia de Alberta – Canadá, es utilizada para lograr el perfil óptimo de tensiones. La validación del controlador se realiza mediante una simulación sobre un caso de biblioteca y se compara la solución obtenida con la brindada por un flujo óptimo de potencia y con la de un algoritmo genético. Como resultado fundamental se obtiene el tratamiento unificado del perfil de tensiones y el despacho óptimo de la potencia reactiva sin necesidad de recurrir a un algoritmo de dos pasos. El controlador propuesto resulta apto para su aplicación en línea y en tiempo real, así como flexible a la hora de tratar con problemas de difícil formulación analítica.

Se presenta el modelado y simulación de un dispositivo que forma parte de un esquema de protección inteligente. 9e propone un seccionador tensión-tiempo como base del sistema de protecciones aplicado a un distribuidor urbano-rural de electricidad. Se muestra el impacto de la generación distribuida en el esquema implementado y la utilización de un software de propósito general como herramienta de simulación. Este software permite implementar la máquina de estado finito que modela el seccionador propuesto, base del esquema de protecciones. Un resultado importante de este trabajo es que la utilización del dispositivo propuesto mantiene la coordinación aún frente a la inclusión de la generación distribuida. 9e establece también con claridad la máxima cantidad de seccionadores que pueden ser interconectados en serie.