Design features of the Bad Creek pumped storage project generatorsmotors

The four pumped-storage generator/motors for the Bad Creek project in Oconee County, SC, are distributed. Consideration is given to the general unit construction, the cooling system, the thrust bearing, and the structural design. The most unique design aspect of these units is the arrangement of the forced fan ventilation system, which uses twenty motor-driven fans to direct air in very controlled paths. The adequacy of the system was verified by prototype laboratory testing. Field testing is planned to verify the system and machine efficiencies at the time of unit startup     

The Bad Blumau geothermal project: a low temperature, sustainable and environmentally benign power plant

The 250 kW geothermal project at Bad Blumau is the first geothermal project developed in Austria by the private sector following the deregulation of the electricity industry in this country. What makes the project unique besides its private ownership structure is its ability to generate electrical power and district heating for the Rogner Bad Blumau Hotel & Spa by using a low temperature geothermal resource. Installed in the record time of less than a week, the air-cooled ORMAT ® Energy Converter (OEC) CHP module has been in commercial operation since July 2001. With an annual availability exceeding 99%, between October 2001 and December 2002 the plant delivered 1,560,000 kWh to the local grid. The geothermal CHP module utilizes brine at 110 °C, available from a 3000 m deep production well. Exiting the OEC unit at a temperature of 85 °C, the brine is then fed into the district heating system, providing heat for the Rogner Bad Blumau Hotel & Spa. The geothermal brine is returned from the district heating system and injected into a 3000 m depth reinjection well. The system is a pollution-free, unattended operating power generation module, which has avoided more than 1100 kg of CO₂ emissions over its first operating year.     

The Hydropower Potential Assessment Tool (HPAT): Evaluation of run-of-river resource potential for any global land area and application to Falls Creek,Oregon, USA

Small-scale hydropower systems are popular both in the United States and much of the developing world due to the emphasis on renewable energy and the general cost-competitiveness of hydroelectric power generation. We present a novel modeling package, referred to as the Hydropower Potential Assessment Tool (HPAT), to assess historic and projected future small-scale run-of-river hydropower resource potential at a single location or distributed over a study region. HPAT implements a fully-distributed streamflow model, which is coupled to a digital elevation model to assess hydropower resource potential. To demonstrate HPAT, we implement the models for a privately-owned run-of-river facility on Falls Creek outside of Sweet Home, Oregon, USA. We use an ensemble of Global Climate Models (GCMs) for two future climate scenarios to project a plausible range of future changes at this site. For the Falls Creek facility, HPAT projects that the timing of peak streamflow will shift from spring to winter and that mean annual hydropower potential will likely decrease slightly from average 1980–2010 historic conditions through the end of the 21st century. All inputs to HPAT are globally available, except for streamflow observations necessary for calibration.     

Electrical/mechanical options for variable speed wind turbines

The use of variable speed wind turbines, especially in large-scale utility electricity generating systems, offers a potential improvement in the cost effectiveness of wind energy systems. This paper presents a review of the potential options (including mechanical, electrical/mechanical, electrical, and electrical/power electronic) open for variable speed wind turbine design and gives some of the advantages and disadvantages of these design options. As summarized, a major design problem is to build a system that will allow the rotor to turn at a variable speed, while the machine is feeding power of constant frequency to the load. Although many approaches have been suggested for variable speed operation, they can be grouped into two main classes: (i) discretely variable, and (ii) continuously variable. It is concluded that, based on the current state-of-the-art, the systems with the most promise appear to be those incorporating power electronics.     

Network security protection technology for a cloud energy storage network controller

As part of the ongoing information revolution, smart power grid technology has become a key focus area for research into power systems. Intelligent electrical appliances are now an important component of power systems, providing a smart power grid with increased control, stability, and safety. Based on the secure communication requirements of cloud energy storage systems, this paper presents the design and development of a node controller for a cloud energy storage network. The function division and system deployment processes were carried out to ensure the security of the communication network used for the cloud energy storage system. Safety protection measures were proposed according to the demands of the communication network, allowing the system to run safely and stably. Finally, the effectiveness of the system was verified through a client-side distributed energy storage demonstration project in Suzhou, China. The system was observed to operate safely and stably, demonstrating good peak-clipping and valley filling effects, and improving the system load characteristics.     

Design, construction, and ocean testing of a taut-moored dual-body wave energy converter with a linear generator power take-off

This paper presents an overview of the SeaBeavI project which began in the fall of 2006 and culminated in the ocean testing of a 10 kW direct-drive wave energy conversion system in the fall of 2007. The SeaBeavI project was an interdisciplinary effort bringing together researchers from electrical, mechanical, and ocean engineering. A systems design approach was used to develop the taut-moored dual-body wave energy converter concept with the detailed design focused on production and ease of maintenance.     

Design features of the Murray Hydroelectric Project

The Murray Hydroelectric Project, a two-unit, 39 MW total rated capacity, run-of-the-river facility located on the Arkansas River, is described. The emphasis of the paper is on the project's electrical features. The two generating units are of an open-pit design with horizontal double-regulated turbines. Turbine rated speed in 46 RPM. The generator is rated 22.77 MW at a power factor of 0.9. The rated voltage is 6.9 kV. The author also discusses the plant's mechanical-hydraulic governor, its electrical system, a 5.7 mile (9.2l-km), 115 kV transmission line, the plant's black-start capability, its mechanical systems, and the plant, unit, and offsite control systems     

基于分布式供能技术的能源系统

由于2003年美国和加拿大大面积停电事故的发生，人们对电网安全的要求越来越高，分布式供能技术引起了世界能源界的广泛关注。能源工业亟待解决的四大问题：合理调整能源结构，进一步提高能源利用效率，改善能源产业的安全性，解决环境污染。而分布式能源系统恰好在这些方面能给以补充，因此大电网与分布式能源系统的合理结合，被认为是21世纪电力工业的发展方向。详细介绍了基于分布式能源系统的概念、特点及发展状况和前景展望。还通过对几种主要的分布式供能技术的技术特点、国内外发展状况及前景展望的介绍，进一步说明了分布式供能技术的发展状况，阐释了分布式供能技术的优势。     

On the parasitic power of solar absorption cooling systems and criteria for operational control

This paper investigates the amount of electrical power required, on top of thermal energy needs, in order to generate and deliver the cooling effect of solar absorption cooling systems as compared with the electrical power needs of equivalent vapour compression cooling systems. Further, the effects of degraded operating temperatures and partial load conditions on the power cost per unit of cooling effect in both systems are investigated. It is shown that, under unfavourable conditions, power cost in both systems will be equal. This condition is attained when the two equivalent systems operate at about one-third of their design cooling capacity. It is argued that electrical power saving with solar absorption systems would be improved if a multi-unit configuration is used instead of single unit configuration.     

Design of grid connected PV systems considering electrical, economical and environmental aspects: A practical case

This paper presents the complete design of a photovoltaic installation that may be either used for internal electric consumption or for sale using the premium subsidy awarded by the Spanish Government. Electric optimization strategies are detailed in the project, as well as the sizing of the photovoltaic installation and economic and financial issues related to it. The project optimizes the electricity demand, improving reactive power and studying the convenience of hourly discrimination fees in addition to the design of the photovoltaic installation. A specific computer application for the automated calculation of all relevant parameters of the installation—physical, electrical, economical as well as ecological—has been developed to make the process of calculating photovoltaic installations easier and to reduce the design development time. Moreover, the budget of the photovoltaic installation is included, as well as its corresponding financial ratios and payback periods. Finally, the conclusions reached in the technical and economic design of the installation are shown.     

Comparative study of different fuel cell technologies

Fuel cells generate electricity and heat during electrochemical reaction which happens between the oxygen and hydrogen to form the water. Fuel cell technology is a promising way to provide energy for rural areas where there is no access to the public grid or where there is a huge cost of wiring and transferring electricity. In addition, applications with essential secure electrical energy requirement such as uninterruptible power supplies (UPS), power generation stations and distributed systems can employ fuel cells as their source of energy.The current paper includes a comparative study of basic design, working principle, applications, advantages and disadvantages of various technologies available for fuel cells. In addition, techno-economic features of hydrogen fuel cell vehicles (FCV) and internal combustion engine vehicles (ICEV) are compared. The results indicate that fuel cell systems have simple design, high reliability, noiseless operation, high efficiency and less environmental impact. The aim of this paper is to serve as a convenient reference for fuel cell power generation reviews.     

Design improvements for ammonia-fed SOFC systems through power rating,cascade design and fuel recirculation

In this paper, design strategies for improving electrical efficiency, thermal design and fuel utilization of an ammonia-fed SOFC are investigated. Three strategies are presented to improve system performances: (i) the introduction of an additional stack to distribute the power i.e. power rating, (ii) the evaluation of the anode off gasses recirculation and (iii) the use of the off gasses to operate a cascade stack (re-powering), where the anode flue gas is recuperated. A system design that integrates these new features is modelled with zero-dimension thermodynamic equations. The three strategies were evaluated for net system efficiency and the heat exchanger area as main design parameters. The power rating allows to reduce the heat exchanger surface while the recirculation and repowering are suitable to increase system efficiency. With an integration of the three solutions, it is possible to achieve an increase in net efficiency from 52.1% to 66% and a reduction in heat exchanger surface area of 67% compared to the reference design that does not consider any of the proposed design strategies.     

Overview of energy storage systems for storing electricity from renewable energy sources in Saudi Arabia

Renewable power (photovoltaic, solar thermal or wind) is inherently intermittent and fluctuating. If renewable power has to become a major source of base-load dispatchable power, electricity storage systems of multi-MW capacity and multi-hours duration are indispensable. An overview of the advanced energy storage systems to store electrical energy generated by renewable energy sources is presented along with climatic conditions and supply demand situation of power in Saudi Arabia. Based on the review, battery features needed for the storage of electricity generated from renewable energy sources are: low cost, high efficiency, long cycle life, mature technology, withstand high ambient temperatures, large power and energy capacities and environmentally benign. Although there are various commercially available electrical energy storage systems (EESS), no single storage system meets all the requirements for an ideal EESS. Each EESS has a suitable application range.     

重型燃气轮机联合循环电厂全厂一体化控制应用

重型燃气轮机联合循环电厂往往采用多个控制系统来实现全厂控制,如果采用统一控制平台进行全厂一体化控制,相比多个控制系统具有许多优点。本文以华能金陵燃机电厂控制系统为案例,对重型燃气轮机全厂一体化控制的设计和应用进行了分析和介绍,为联合循环发电厂控制一体化的设计及实现提供了可借鉴的经验。     

Modelling,simulation and control of a proton exchange membrane fuel cell (PEMFC) power system

Fuel cell power systems are emerging as promising means of electrical power generation on account of the associated clean electricity generation process, as well as their suitability for use in a wide range of applications. During the design stage, the development of a computer model for simulating the behaviour of a system under development can facilitate the experimentation and testing of that system's performance. Since the electrical power output of a fuel cell stack is seldom at a suitable fixed voltage, conditioning circuits and their associated controllers must be incorporated in the design of the fuel cell power system. This paper presents a MATLAB/Simulink model that simulates the behaviour of a Proton Exchange Membrane Fuel Cell (PEMFC), conditioning circuits and their controllers. The computer modelling of the PEMFC was based on adopted mathematical models that describe the fuel cell's operational voltage, while accounting for the irreversibilities associated with the fuel cell stack. The conditioning circuits that are included in the Simulink model are a DC–DC converter and DC–AC inverter circuits. These circuits are the commonly utilized power electronics circuits for regulating and conditioning the output voltage from a fuel cell stack. The modelling of the circuits is based on relationships that govern the output voltage behaviour with respect to their input voltages, switching duty cycle and efficiency. In addition, this paper describes a Fuzzy Logic Controller (FLC) design that is aimed at regulating the conditioning circuits to provide and maintain suitable electrical power for a wide range of applications. The model presented demonstrates the use of the FLC in conjunction with the PEMFC Simulink model and that it is the basis for more in-depth analytical models.     

Electric heat tracing systems-standards development (IEEE PowerGeneration Comm. Report)

Standards development activities at IEEE in the area of electric heat tracing systems is reviewed, and the pertinent standards are summarized. They are: IEEE Std 622-1979, recommended practice for the design and installation of electric pipe heating systems for nuclear power generating stations; IEEE Std 515-1983, Recommended practice for the testing, design, installation and maintenance of electrical resistance heat tracing for industrial applications; and two standards in the development process, IEEE Std 622-198(6), Recommended practice for the design and installation of electric heat tracing systems for nuclear power generating stations, and Project 622B, Recommended practice for testing and startup procedures for electric heat tracing systems for power generating stations     

Modeling of solid oxide fuel cells for dynamic simulations of integrated systems

Solid oxide fuel cell (SOFC) stacks are at the core of complex and efficient energy conversion systems for distributed power generation. Such systems are currently in various stages of development. These power plants of the future feature complicated configurations, because the fuel cell demands for a complex balance of plant. Moreover, proposed SOFC-based systems for stationary applications are often connected to additional components and subsystems, such as a gasifier with its gas-cleaning section, a gas turbine, and a heat recovery system for thermal cogeneration or additional power production. For the simplest SOFC configurations, and more so for complex integrated systems, the dynamic operation of the power plant is challenging, especially because the fluctuating electrical load of distributed energy systems demand for reliable transient operation. Issues related to dynamic operation must be studied in the early design stage and simulation results can be used to optimize the system configuration, taking into account transient behavior. This paper presents the development and the validation of a non-linear dynamic lumped-parameters model of a SOFC stack suitable for integration into models of complex power plants. Particular emphasis is placed on the systematic approach to model development. The model is implemented using the open-source Modelica language, which allows for a high degree of flexibility and modularity, the main features of the model herein presented. The SOFC stack model will be incorporated into ThermoPower, a freely distributed library of reusable software components for the modeling of thermo-hydraulic processes and power plants.     

A graphical user interface for design, simulation and analysis ofpower plant electrical auxiliary systems

An interactive graphical user interface (GUI) package for the design, simulation and analysis of a power plant electrical auxiliary system is presented in this paper. The purpose of this package is to assist the engineer in performing nonreal-time, what-if, analysis in an interactive and intuitive environment. The package, AUXSYS, is capable of performing load flow and motor starting simulations. It provides a graphical interface for designing the one-line diagram of the plant and analyzing the output of the simulations. It is currently used for modelling Wisconsin Electric Power Company's (WEPCO) power plant electrical auxiliary systems and is implemented for use on PCs