Denisson Queiroz Oliveira

Artificial Immune Systems Optimization Approach for Multiobjective Distribution System Reconfiguration

In order to optimize their assets, electrical power distribution companies seek out various techniques to improve system operation and its different variables, like voltage levels, active power losses and so on. A few of the tools applied to meet these objectives include reactive power compensation, use of voltage regulators, and network reconfiguration. One target most companies aim at is power loss minimization; one available tool to do this is distribution system reconfiguration. To reconfigure a network in radial power distribution systems means to alter the topology changing the state of a set of switches normally closed (NC) and normally opened (NO). In restructured electrical power business, a company must also consider obtaining a topology as reliable as possible. In most cases, reducing the power losses is no guarantee of improved reliability. This paper presents a multiobjective algorithm to reduce power losses while improving the reliability index using the artificial immune systems technique applying graph theory considerations to improve computational performance and Pareto dominance rules. The proposed algorithm is tested on a sample system, 14-bus test system, and on Administración Nacional de Electricidad (ANDE) real feeder (CBO-01 23-kV feeder).

Control Strategies for Improving Energy Efficiency and Reliability in Autonomous Microgrids with Communication Constraints

Microgrids are a feasible path to deploy smart grids, an intelligent and highly automated power system. Their operation demands a dedicated communication infrastructure to manage, control and monitor the intermittent sources of energy and loads. Therefore, smart devices will be connected to support the growth of grid smartness increasing the dependency on communication networks, which consumes a high amount of power. In an energy-limited scenario, one of the main issues is to enhance the power supply time. Therefore, this paper proposes a hybrid methodology for microgrid energy management, integrated with a communication infrastructure to improve and to optimize islanded microgrid operation at maximum energy efficiency. The hybrid methodology applies some control management rules, such as intentional load shedding, priority load management, and communication energy saving. These energy saving rules establish a trade-off between increasing microgrid energy availability and communication system reliability. To achieve a compromised solution, a continuous time Markov chain model describes the impact of energy saving policies into system reliability. The proposed methodology is simulated and tested with the help of the modified IEEE 34 node test-system.

An artificial immune approach for service restoration in smart distribution systems

The power system reconfiguration is a challenging task. As smart grids concepts develop, different approaches try to take advantage of the grid intelligent features and infrastructure to evolve a fast and robust self-healing scheme. At the distribution level, the self-healing schemes are responsible for performing automatic corrective and self-restorative actions. This task includes managing the service restoration by locating and isolating the fault, and reconfiguring the network topology to decrease the harm. This paper presents a self-healing scheme using Artificial Immune System as an optimization tool to solve the service restoration problem in power systems considering faults within the internal switch breakers. To make this approach suitable for bigger systems, the Prim Algorithm is used due to its capacity to generate minimum spanning trees from a graph. The proposed scheme is tested on benchmark systems to investigate the capacity of proposing feasible solutions for faulted systems.

Unbalanced load flow for microgrids considering droop method

Power systems are under a huge transformation because of the growing penetration of renewable sources. In this sense, microgrids may become a reality, since local sources and manageable loads and batteries may help the system to be self-sustainable under emergency conditions. This paper proposes a three phase power flow for microgrids which considers the droop method. Hence, frequency and voltage level at the sources may vary. The proposed approach is tested with the help of a modified IEEE 34 test system.

Negative Selection of Artificial Immune Applied to Voltage Inadequacy Detection in Distribution Networks

Abstract The problem of voltage control and reactive power management plays a crucial role on power system’s operations. Particularly, detecting the most effective control actions to reduce the system loss and enhance the voltage profile is of major interest. This paper deals with system voltage inadequacy detection. To address this problem, artificial immune system is employed considering its negative selection mechanism. Its purpose is to monitor system operation data entry and check if the voltage level is within its operating values. In this sense, the user may define the range of control, so the proposed methodology may be useful for normal and emergency operating conditions. Corrective actions are undertaken if necessary. The IEEE 34 nodes distribution system is used to test the proposed methodology.

Microgrids Operation in Islanded Mode

The smart grid concept is intended to improve power system operation and control. A feasible path to make the system smarter is through microgrids deployment. A microgrid is a small scale-power system with its own power generation units and deferrable loads, and it may work islanded or connected to the main power grid. The main objective of microgrids in islanded mode is to allow the system to operate even in adverse scenarios, such as faults in main grid, high prices of main grid’s power, and supplying remote areas. In the case of an islanding, high priority loads, such as hospitals, transportation and telecommunication facilities must have their supply assured. This is possible due to the penetration of Distributed Energy Resources (DERs), including renewable, fossil, combined heat and power, and energy storage units. However, the operation of microgrids in islanded mode requires more attention due to the higher outage risk since the power generation capacity is limited. Consequently, microgrids may be provided by an Energy Management System (EMS) responsible for managing the scarce power resources to maintain the supply for the highest priority customers connected to the grid. Such management strategy is a complicated and ambitious task and demands a robust and reliable communication system. This chapter investigates some control and management issues in microgrids islanded operation mode. Firstly, the main features and requirements of islanded mode in comparison with connected mode are described. Some discussions about control requirements on different control levels are presented. Communications networks are also discussed. These communications networks enable the expected smart features in the microgrids through the bidirectional data flow. The steps for designing a mobile telecommunication network for a microgrid are described, and a study case considering a small microgrid is investigated to show the communication network design steps and the operation of an islanded microgrid during one day.

Overview on Microgrids: Technologies, Control and Communications

The modern society is highly dependent on electricity. At the same time, there is a huge concern about the greenhouse gas emissions and the current way of power generation, mainly with fossil fuels and high costs. The deployment of microgrids may be a solution for both questions. They are a solution to the supply reliability problem through the existent distributed energy resources (DERs) connected to the grid near customers, and the environmental concern is met by applying renewable sources to generate power. Beyond these goals, there is a supply cost reduction and revenue maximization through power trades with the main grid, which is also considered as desired matches. Using proper control strategies and robust communications techniques, microgrids generate, distribute and regulate the flow of power to consumers through a centralized or decentralized control. Smart microgrids are an ideal way to integrate renewable resources on the community level and allow for customer participation in all levels of the power market. Hence, a distribution system may evolve to a microgrid that may become a smart grid. Because the level of intelligence, communication, and control may vary, this chapter assumes the term microgrids in a general sense, which may stand for an ordinary microgrid or a smart grid. The goal of this chapter is to provide a brief overview on microgrids, including the state of art about the main motivation for the emergence of these networks. A survey on some existing microgrids around the world focusing on the different architecture and applications, e.g., hospitals, military bases and small isolated communities is carried out. Next, a typical microgrid’s architecture is presented. Some other topics regarding generation resources, energy storage options, suitable communication technologies, and infrastructure are discussed. From the economic and social point of view, microgrid’s effects are addressed by highlighting the main benefits. In addition, technical issues and future challenges are discussed in this chapter.

Index for allocation of tidal current power plant for reactive margin improvement

The oceanic energies from tidal currents have been drawing attention around the world, and many small power plants were deployed. The allocation of renewables in the power grid must consider some requirements, including the voltage stability. This paper presents an index for evaluating the best site to allocate a tidal current power plant in the power system, considering an improvement in the QV margin in the buses near the renewable-based plant.

Plug-in Electric Vehicles Management in Smart Distribution Systems

The advent of smart grids brings a set of new concepts not usually employed in current power systems. Plug-in electric vehicles fit this concept, since it is a low carbon emission device. However, an important characteristic of plug-in vehicles lies on the fact that it may become a source of energy during emergency conditions. Another aspect that may not be overlooked is the fact that the advantage of low carbon emission may be faded by the fact that charging these vehicles may deteriorate the network operating conditions. In this sense, a recharging policy must be addressed, so the system losses and voltage profile are adequately managed. This chapter deals with these topics, so the advent of plug-in electric vehicles may be understood as an important component of future smart grids.

Overview of Plug-in Electric Vehicles Technologies

The advent of renewable energy is about to change power systems around the world. In this sense, operating a power system may become an even more complex task, with implications on the system security, reliability and market. The role played by the utilities may not be diminished, since they must be able to provide energy when intermittent sources are not available. In this near future, the plug-in electric vehicles will also have an important role for power distribution systems. But, at the same time, they have a big potential to help on integration of the renewable power generation in existing power systems. This chapter presents some of the existing plug-in electric vehicles technologies and discusses a few implication of this new scenario in the system operation.