Electrical System Configuration Research Articles

Solar Power Supply in the System of Restoration and Reconstruction Remote Historic and Cultural Objects (on the Example of Montenegro)

There is a great number of historic and cultural monuments on the territory of Montenegro, which should be preserved and maintained. Their distance from centralized networks and the lack of conditions for restoration make difficult to maintain them properly. The article puts forward the options for architectural incorporation of solar power systems into the appearance of historic buildings and structures. In the article is proposing the configuration of electrical systems based on the results of the calculation of one energy source (solar/diesel plant) and their combination.

Model study of a fuel cell range extender for a neighborhood electric vehicle (NEV)

Abstract Fuel cell systems have the potential to provide high-efficiency, low-cost power for Neighborhood Electric Vehicles (NEVs). Model results are presented examining the utility of placing a hydrogen PEM fuel cell on-board a Miles Electric ZX40ST work truck NEV as an “after-market add-on” range extender to the existing battery electric drive train, thereby creating a NEVx. Through the development and use of the Sandia-Miles-Altergy Range Test (SMART) model, we have examined the potential for a number of PEM fuel cell stack systems (with varying output power), combined with various hydrogen storage and electrical storage system configurations to achieve the desired range extension for a single 8-h work shift. Furthermore, we have evaluated the “well-to-wheels” (WTW) and greenhouse gas (GHG) reductions, and assessed the costs (both capital and O&M) for the different NEVx configurations and operating profiles. This analysis demonstrates that a NEVx incorporating a PEM fuel cell range extender provides a viable means of providing the desired range (or equivalently the runtime) while increasing the vehicle's versatility and maintaining its zero-emissions rating. A 5 kW fuel cell system with 2.6 kg of hydrogen stored at 2265 psi in conventional steel cylinders can meet the demands of the low-power duty cycles envisioned for the NEVx. A slightly higher powered NEVx with a 7.5 kW fuel cell offers the same advantages in operating profiles that require more power, for example with frequent starts, sustained higher speeds, or hilly routes. While currently expensive, the total cost per mile of the fuel cell range extender is comparable to conventional gasoline vehicles. The WTW GHG emissions of the NEVx are 40%–85% lower than those for a comparable gasoline powered vehicle, depending on the particular drive profile and sources of both hydrogen and electricity. The analysis shows that a fuel cell range extender can maintain the vehicle battery pack at a high state of charge (SOC) throughout the operating profile, thereby extending overall battery life and reducing charging time. The fuel cell range extender is currently envisioned as a drop-in retrofit for the existing Miles Electric ZX40ST work truck. However, with sufficient demand, a fully integrated new vehicle system could be both more efficient and less expensive. If designed into the NEVx from the start, the cost, weight, and emissions could all be reduced while increasing the payload space and versatility.

Proposal of a nearly zero energy building electrical power generator with an optimal temporary generation–consumption correlation

This study presents an electrical photovoltaic (PV) power generator system, which was designed, built, and tested during the Solar Decathlon Europe 2012 competition as part of the SMLsystem, i.e., the CEU Cardenal Herrera University prototype. One of the main aims of the contest was to evaluate the prototype's electrical energy balance capacity in terms of self-sufficiency, low energy consumption, and the temporary generation–consumption correlation demand. The design and evaluation were determined according to the competition rules and a framework was built for a type of nearly zero energy building (nZEB), where the specific criteria required that all the necessary energy was obtained from the sun. Various aspects were considered in the design of the PV system, including the energy demand and disposability, possibility of grid connection, power installation, appropriate battery capacity, electrical PV system configuration (AC coupling and/or DC coupling), and the temporary generation–consumption correlation demand. To achieve an optimal energy balance, the electrical PV power generator system design strategy focused on the energy correlation analysis behavior and the efficient management of the energy system, while maintaining the main load of the nZEB at a sufficiently low level using a timed controller.

Smart grid opportunities and applications in Turkey

Abstract A smart grid is a system that uses information and communication technologies to integrate, in an intelligent way, all users connected to the electrical power system considering their behaviour and actions. For this purpose, information about the electrical network, such as the current, the voltage or the power, is gathered together over time so that the behaviour of suppliers and consumers can be observed and automatically coordinated. Smart grids are becoming a significant part in the configuration of future electrical power systems. A lot of research has been done on using smart grids to achieve highly efficient and user-friendly electrical power systems. Many new methods have been introduced to solve the difficulties energy providers face when transforming conventional electrical networks into smart grids. These difficulties include the integration of renewable energy and different grid systems at national and international levels due to changes in frequency, voltage and in the synchronisation mechanism. This paper provides an outline of the European smart grid projects and gives an overview of the current infrastructure and smart grid applications of the Turkish Electricity Production System Operator (EUAS), Turkish Electricity Transmission System Operator (TEIAS), and Turkish Electricity Distribution System Operator (TEDAS). In this paper the feasibility of the further steps required is described and some assessments are made and suggestions given on smart grid developments in general.

Visualization in a Virtual Laboratory: An Approach Using a Collaborative Simulation for Electro-Mechanical System

In an electro-mechanical integration system where loads consist of a mechanical system, the electrical system specification and configuration will depend on the mechanical system. Therefore, inaccurate parameters of the mechanical system will make difficult the selection of electrical system specification and the effective controller design. Of these, the controller design often adopts an experimental method or a method using numerical analysis. With such methods, however, it is difficult to predict the actual system in advance followed by specification selection and controller design. Hence, to perform a faster and more accurate modeling of the system, a collaborative analysis is required for two physically different systems in a virtual space. In the present article, a method of an electro-mechanical collaborative analysis is proposed for an elevator door drive system. From mechanical load modeling using simulation, an electrical requirement specification has been derived. In addition, a C++-based collaboration program has been developed that can connect mutually different physical domains according to the proposed collaborative analysis procedures. The proposed modeling technique and program have been verified through simulation and experimental result.

Daylight Impact on Energy Performance of Internal Lighting

Daylight in interior offers a considerable contribution of energy saving, the key is to design an integrated lighting system between the electric lighting system configuration and its control strategy. An optimal lighting system has to consider the different presence of daylight in the zones to arrange the most favorable luminaires layout. An automatic control system could be employed to switch or dim selected groups of luminaires. The paper suggests a criterion to evaluate the yearly daylight impact on energy performance of internal lighting according to daylight availability, the lighting system layout, and the control system arranged. A simplified evaluation by the daylight lumen method is useful for designers to estimate the operation costs in reference to the initial costs in preliminary design.

Model predictive control of a power-split hybrid electric vehicle system

This paper presents a model predictive control approach for the energy management problem of a power-split hybrid electric vehicle system. The model predictive control is suggested to optimally share the road load between the engine and the battery. By analyzing the configuration of the power-split hybrid electric vehicle system, we developed a simplified model for better implementation of model predictive control. The model predictive control problem is solved using numerical computation method: continuation and generalized minimum residual method. Computer simulation results showed that the fuel economy was better using the model predictive control approach than the ADVISOR rule-based approach in three cases. We conclude that the model predictive control approach is effective for the application of power-split hybrid electric vehicle systems energy management and has the potential for real-time implementation. The simplified modeling method of the power-split hybrid electric vehicle system configuration can be applied to other configurations of hybrid electric vehicle.

Optimal energy management of small electric energy systems including V2G facilities and renewable energy sources

The emerging of plug-in hybrid vehicles results not only in the increase of electric vehicles as means of transportation, but also in the utilization of vehicle batteries for grid support, which is referred to as vehicle-to-grid (V2G). However, V2G is still at a conceptual stage, and the lack of practical and realistic frameworks to help moving from concept to implementation causes serious challenges to its adoption. In this context, this paper proposes a practical model for the assessment of the contribution of V2G systems as a support to energy management within realistic configurations of small electric energy systems (SEESs) including renewable sources, such as Microgrids. Considering the uncertainty factors related to renewable power sources and gridable vehicles, the model materializes into a robust linear optimization problem suited to be easily integrated in the Energy Management System of SEESs, to support – in operation or operation planning – SEESs’ participation in the electricity market. The paper also presents a practical methodology to model the aggregation of gridable vehicles, contributing to the literature in the field and helping towards the actual implementation of V2G. The efficiency and usefulness of the developed aggregation and optimization models are shown using a realistic SEES case study.

Mitigating Electric Shock and Arc-Flash Energy: A Total System Approach for Personnel and Equipment Protection

This article provides a comprehensive discussion of the application and selection of various techniques and technologies available for the reduction and mitigation of arc-fault hazards to personnel and equipment. It also presents a broad approach that considers the total electrical system configuration and design. No technology can address all safety concerns. Current available technologies, such as optical light detection, pressure detection, temperature detection, and current signatures, for reducing arcflash hazard are discussed, and the advantages and disadvantages of each technique are outlined. An analysis is presented about how a total system approach can optimize the benefits of various technologies by using complementary technologies such as impedance grounding, equipment construction, and operational techniques. The importance of the fundamental power system configuration selection, equipment design aspects, and maintenance is also discussed.

Integration of Wind and Hydropower Systems: Results of IEA Wind Task 24

In May of 2004, the IEA Wind Implementing Agreement (IA) established R&D Task 24, “Integration of Wind and Hydropower Systems.” Australia, Canada, Finland, Norway, Sweden, Switzerland, and the United States joined Task 24 with the goal of collaborating in the study of wind integration in a variety of electrical system configurations (load, generation, and transmission); hydro system configurations and characteristics; and market and operational configurations. Representing these countries were utilities and research organizations with the intent to understand the potential for and limiting factors in integrating wind into systems with hydropower. Case studies that analyze the feasibility, benefits, detriments, and costs of specific wind-hydro integration projects were the mechanism through which the goals of the task were addressed. The purpose of this article is to summarize the framework within which these studies were performed, and to present the key results and the general conclusions of the Task.

Multi-megawatt offshore wave energy converters – electrical system configuration and generator control strategy

Considerations of the electrical system configuration and the control strategy for the wave dragon (WD) multi-megawatt (MW) offshore wave energy converter (WEC) are presented in this study. The electrical system consists of 16–20 turbine–generator–AC/DC/AC converter units. The characteristics of the low-head water-turbine and generator control strategy enabling maximum energy capture and the best performance for the MW offshore wave energy power take-off system are described in detail. Simulation results from a single turbine–generator–frequency converter unit at different turbine heads are presented at the end of the study.

Optimización de Redes Eléctricas Mediante la Aplicación de Algoritmos Genéticos

This work proposes the optimization of the topological configuration of secondary electrical distribution networks to minimize technical losses produced during their exploitation due to Joule effect, using for this Genetic Algorithms. Through the application of the method to two systems, it was found that the optimization technique is able to find the optimum solution among all the possible combinations that switch operations offer. Its flexibility to adapt to the restrictions of radiality and voltage level in less time than that of exhaustive search is also proved. During the development of the application the genetic operators were validated, determining those that gave the best performance in the search of the solution. The results show the feasibility and viability of the application for the optimum configuration of electrical distribution systems.

Topological Overview of Hybrid Electric and Fuel Cell Vehicular Power System Architectures and Configurations

This paper discusses the operational characteristics of the topologies for hybrid electric vehicles (HEV), fuel cell vehicles (FCV), and more electric vehicles (MEV). A brief description of series hybrid, parallel hybrid, and fuel cell-based propulsion systems are presented. The paper also presents fuel cell propulsion applications, more specific to light-duty passenger cars as well as heavy-duty buses. Finally, some of the major fundamental issues that currently face these advanced vehicular technologies including the challenges for market penetration are highlighted.

Power system disturbance patterns

Power system disturbances (e.g. surges) may or may not affect the performance of sensitive electronic and electrical equipment. When the performance of a utility's customer's sensitive equipment is significantly affected by alleged power supply disturbances, then the utilities may become involved in a complex process of detecting the possible patterns of the occurrences of these disturbances which may identify the origins of the power supply anomalies affecting the customer's electronic equipment. The activities, involving the utility and its customers, directed at mitigating the impact of power system disturbances on sensitive electronic equipment are discussed. The importance is stressed of having an adequate knowledge of the utility and its customer's electrical power system configurations and their operational activities prior to initiating a monitoring scheme to detect power supply anomalies. The disturbance patterns in a power supply system monitored continuously at a single site over a two-year period are presented, and the problems that might evolve from short-term site monitoring are discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Electrical power system for low-earth-orbit spacecraft applications

The results of a trade off study to select an electrical power system (EPS) configuration that is best suited for low-Earth-orbit (LEO) spacecraft with various output power capabilities are presented. The selection is based on parameters like weight, volume, and costs of the power system components. Two EPS configurations used for LEO spacecraft, i.e., one using a direct energy transfer (DET) approach, and the other using a peak power transfer (PPT) approach, are described in detail and compared. At a spacecraft power requirement of 800 W or less, it is highly advantageous to choose the PPT approach to the design of an EPS for LEO spacecraft. However, for a spacecraft in higher orbit and/or with higher power requirements, the DET-based power system is the optimum choice.

Real-time expert systems for advanced power control (a status update) (aerospace power system testbed)

The most recent developments in the Boeing Aerospace Autonomous Power System (APS) testbed are presented. The APS testbed is a 28-VDC system with 3-kW capability, assembled for use in developing improved control, techniques for aerospace electrical power systems. The main emphasis is on the development of a sophisticated programming environment to control concurrent execution of multiple autonomous algorithms coupled with a continuous input/output data flow. The integration of high-level control algorithms used for battery charge control into a real-time execution environment is discussed. This includes methods that allow several functions to respond to real-time input, affect/maintain expert system (shared) memory, and control the electrical power system configuration. Sophisticated schemes for scheduling these expert system control functions are required to allow real-time multitasking.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Power measurement and harmonic analysis of large adjustable speed drives

Details are given of two power electronics adjustable speed drives, (ASDs) that were installed on utility power-plant boiler-feed-pump motors for conversion to speed control. One is a 2250 HP modified load commutated inverter with six pulse input and six pulse output. The other is a current-source inverter with 12 pulse input rectifier and 12 pulse output inverter. The authors show electrical system configuration, input and output current, and voltage wave shapes for each system. Means for measuring power and harmonics in power plant ASD installations using a real-time spectrum analyzer are discussed. ASD efficiency and measured additional motor losses from harmonics as determined in the field are presented.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Factors influencing the protection of small-to-medium size induction generators

The performance and unique characteristics of induction generators as they relate to the protection of the units are discussed. Machines in the range of several kW up to 1500 kW are considered. Contrasts are provided to demonstrate the differences in protection suggested for traditional synchronous generators and induction units. The need for overvoltage protection due to self-excitation of induction generators under load rejection is addressed. Recommendations are provided for the minimum amount of protection on these units in several electrical system configurations as they might apply to single or multiple-unit installations. >

Impact of CCV Requirements on Flight Control System Design

The advent of Controlled Configured Vehicle (CCV) design approaches has imposed severe reliability and fault tolerance requirements on aircraft flight control and supporting systems. This paper establishes the requirements for, and develops the configuration of, an integrated fly-by-wire (FBW) flight control system suitable for an unstable CCV fighter/attack aircraft design. The hydraulic and electric power systems are an integral part of the design problem, since their functions are essential to safety of flight. A three-channel FBW system configuration was chosen as optimum. The system features in-line monitored active/on-line secondary actuators, skewed rate gyros, triplex digital computers, accelerometers, and pilot input transducers. I. Introduction T HE advent of Controlled Configured Vehicle (CCV) design approaches has imposed severe reliability and fault-tolerance requirements on aircraft flight control and supporting systems. The objective of the study reported in this paper was to establish the requirements for, and to develop the configuration of, an integrated fly-by-wire (FBW) flight control system suitable for an unstable CCV fighter/attack aircraft design. The sensor, computer, and actuator subsystems were addressed, as well as the hydraulic and electric power sources. The hydraulic and electric power systems are an integral part of the design problem, since their functions are essential to safety of flight. Several advanced fighter/attack aircraft designs were examined to establish generic characteristics and mission requirements. A typical control surface complement was selected and multimode control law requirements were formulated. This enabled determination of the flight control system design requirements, including flight safety, mission reliability, and failure tolerance. The study approach was twofold. First, several design tradeoffs were performed to examine specific details of the system design for which the optimal approach was not well established. These investigations examined the following areas: 1) hydraulic system configuration, 2) electric power system configuration, 3) self-test/in-line monitoring considerations, and 4) command (secondary) actuator approach. Upon completion of the design tradeoffs, an overall FBW system configuration study was performed. It investigated redundancy requirements, cross-strapping/voting locations, and cost-weight-power tradeoffs. A significant aspect of this paper is that it examines the applicability of the various redundancy techniques to each subsystem of a FBW system. A blend of these techniques, different for each subsystem, was found to achieve the optimum FBW system configuration.

Second Paper: Failure-Survival Automatic Flight Control Systems for Aircraft with Particular Reference to a High Reliability Electrohydraulic Actuator

The author discusses some of the problems of failure-survival automatic flight control systems and suggests some basic ground rules as design criteria. The advantages and disadvantages of some of the main types of system are discussed: duplex, triplex, triple component, duplicate-monitored and quadruplex systems being covered. In particular, a quadruplex actuator is described which has been designed and developed mainly for automatic flight control system applications where a very high degrees of failure-survival capability is required. A detailed failure analysis of the various systems is carried out and the importance of the electrical and hydraulic supply system configurations and failure rates is brought out.