Communications and control options for load management and distribution automation

Distribution automation is an increasingly important function in the electricity delivery system. Distribution automation systems require increasingly sophisticated communication services. This paper reviews the history of SCADA communication systems, discusses the essential ingredients of a modern communication system, and reviews the characteristics of a number of current and emerging communication technologies which can be used to support distribution automation.

In the new business environment, rates for monopoly distribution services (wires), regulators are trying to create a balance between the dollars paid by the consumers and rate of return that the shareholders are allowed to earn. The regulator in Ontario has implemented based regulation (PBR) to regulate the wires part of the distribution system. In PBR, quality of services provided to the customers are considered as one of the performance measurement criteria. Distribution automation and system monitoring are the ways that electric utilities will be able to create innovative ideas for better customer services, improve reliability, defer capital investment and improve system operation. The authors describe the impact of deregulation of electricity utilities on electricity rates and conduct economic analysis to show the benefits of implementing distribution automation and system monitoring in the distribution system planning and operations. In recent years, more and more SCADA, IED and fiber optics have been installed in distribution systems to improve system operation, customer services and generate additional revenue. This paper also describes a planning process for implementing distribution automation. The planning process of distribution automation includes planning strategies, justification of distribution automation functional projects and identification of distribution automation projects. The paper emphasizes on the distribution automatic switching and utilization of integrated communication networks.

A computer and communications system is presented for controlling the operations of load management, distribution automation, and distribution SCADA for a G&T cooperative, Old Dominion Electric Cooperative, and its 12 member cooperatives. The system is currently being designed and delivered by a team of vendors, which involves an EMS/SCADA system vendor and a load management/distribution automation equipment vendor. The system coordinates the scheduling of load management for the member cooperatives so as to minimize the power bills to the power suppliers. Each member cooperative can use the system to implement distribution SCADA and distribution automation functions, thus improving its operation efficiency and service quality. A description is given of the functions, special features, and implementation and development experience for the system. >

Distribution automation started in the 1970s. It allows utilities to implement modern techniques in order to improve the reliability, efficiency, and quality of electric service. Distribution automation is also referred to as feeder automation. It has been defined by the IEEE as follows: 'Distribution Automation is a system that enables an electric utility to remotely monitor, coordinate and operate distribution components in a real-time mode from remote locations'. Distribution automation, commonly known as DA, has evolved into advanced distribution automation, known as ADA, which incorporates advanced communication schemes, new computer technology, state-of-the-art equipment technologies and high-speed power electronic devices.

In the delivery of electricity from the generating station to the consumers, Power Distribution System (PDS) plays a major role. Electric power utilities worldwide are adopting the computer aided monitoring, control and management of PDS to provide better services to the consumers. Recent advances in Information Technology and data communication system are being utilized to automate the electric PDS. The next-generation electricity grid, which is the smart grid, is addressing the major shortcomings of the existing grid. In essence, the smart grid envisages providing utility companies with full visibility and control over their assets and services. This paper presents a review of automation of the Power systems with special emphasis on distribution automation, leading to a smarter grid. The distribution automation and distribution management system functions are discussed in detail and the emergence of a smart grid. The wide area monitoring and control implementation in the transmission sector is also touched upon. The paper also provides some insight into the expansion of laboratory facilities for smart grid implementation and research.

Multipath fading occurs in any environment where there is multipath propagation and there is some movement of elements within the radio communications system. This may include the radio transmitter or receiver position, or in the elements that give rise to the reflections. The multipath fading can often be relatively deep, i.e. the signals fade completely away, whereas at other times the fading may not cause the signal to fall below a useable strength. Multipath fading may also cause distortion to the radio signal. As the various paths that can be taken by the signals vary in length, the signal transmitted at a particular instance will arrive at the receiver over a spread of times. This can cause problems with phase distortion and inter symbol interference when data transmissions are made. As a result, it may be necessary to incorporate features within the radio communications system that enables the effects of these problems to be minimized. This paper analyses the effects of various types of multipath fading in wireless transmission system.

The basic business of distribution utilities has not changed. All utilities must plan, design, construct, operate and maintain their networks. However, utilities are under extreme pressure, due to the deregulation process, to perform these functions efficiently and cost effectively. Utilities are scrambling to put together the tools, processes and training required to meet and exceed customer expectations. The purpose of this paper is to introduce a model or idea that should help distribution utility managers and engineers to evaluate future investments regarding modern secondary systems and other equipment that enable implementation of functions gather under globally accepted term Distribution Automation. Electric utilities must shift their focus from conservative «reliability at all costs» emphasis to a more efficient and economic emphasis. That means that future decisions or calculations regarding investments should be based on both technical and economic studies. Authors suggest that Distribution Automation should be strategic option of distribution utility established in such a way that supports utility's generic strategy. Automation will help distribution utility to achieve the parameters required in the performance-based rates that will be required by the regulatory bodies.

A methodology is described for evaluating the economic feasibility of automation of electric utility distribution systems. Approximately 40 distribution automation functions and subfunctions for the distribution substation, feeder primary, and secondary levels are vels are included with provision fortiondistribu- line carrier, radio, and telephone communication systems. The approach followed is determination of the present value and annual revenue requirements for alternative growth plans, with versus without distribution automation, over a study period of future years. Potential benefits of the functions are evaluated for their economic impact at the generation, transmission, and distribution levels of the utility system. Economic evaluation results are presented based on assumed implementation of selected functions.

In this paper, we investigated existing and proposed WLAN security technologies designed to improve 802.11 standard. Security concerns over WLAN vulnerabilities are explored, and associated techniques are provided to mitigate these vulnerabilities. We also analyzed the existing architecture types of AAA integrated network security solutions, 802.1X and VPNs. We have extensively analyzed the effect of crypto parameters over WLAN based on packet level characteristics. We have also analyzed the effect of TCP and UDP traffic over our proposed WLAN testbed architecture. We found that TCP and UDP traffic behaves erratically, when security index changes causing drastically degradation of system performance. In this paper, we present a detail study of performance overhead caused by the most widely used security protocols such as WEP, IPSEC VPN and 801.1X. Furthermore, we analyze the effectiveness of such solution, based on measurement of security indexing model implementation. Performance measurement indicates that 802.1X and VPN method can be used based on the service time in future wireless systems, while it can simultaneously provide both the necessary flexibility to network operators and a high level of confidence to end users. General Terms: Mobile security, Wireless privacy, And port based Access point.

Three important areas of electric utility distribution system research are identified. These areas deal with planning methods, system surveillance and control, and data file technology. The basic objectives of this project in each of the three areas were to: assess present practices and available tools commonly used in each of the three areas; identify the needs for new techniques, tools, equipment, and other items to improve present practices by making them more efficient, more exact, or more reliable; and recommend research and development required to bring the new techniques, tools, equipment, and other items into existence and to implement their use in distribution system planning methods, system surveillance and control, and data file operation at an early date. A critical review is presented of current practices in the areas of distribution system planning, load forecasting, service reliability, construction and resource management, distribution automation, load management and distribution data base. The recommended research topics in six broad areas expansion planning, reliability evaluation and analysis, economic utilization, information management, distribution automation, and load management are summarized.

By using a combination of a nuclear reactor that emits no carbon dioxide and a high-efficiency gas turbine cycle, electric utilities can reduce their generating cost as well as minimize greenhouse gas emissions. The economic competitiveness of pure natural-gas combined-cycle (NGCC), nuclear-assisted NGCC, and pure nuclear power plants is studied, and the level of CO2 emission tax effects on the cost of electricity from each plant is defined.An advanced gas-cooled nuclear reactor in addition to a conventional NGCC as a heat source for the air exiting the compressor is considered. At a reactor outlet gas temperature of 900°C, the thermal contribution (fossil fuel saving and CO2 reduction) by nuclear energy in the nuclear-assisted NGCC cycle was 46.3%.To assess the economic competitiveness of the plants, the levelized electricity generation costs were calculated. The economics depend primarily on the cost of natural gas and the capital cost of the nuclear reactor. Obviously, the best plant option for low natural-gas cost is pure NGCC and is pure nuclear power for high natural-gas prices. The intersecting points are affected by the assumed carbon tax.Several synergetic effects for using nuclear and fossil powers together are quantified. First, since the electricity generation cost of the nuclear-assisted NGCC cycle is not as sensitive to gas price as the NGCC, the economic risk of fluctuations in gas prices can be minimized by adopting a nuclear-assisted NGCC cycle. Second, the high nuclear capital cost can be largely compensated for by the low capital cost of the gas turbine plant. For example, 3000 $/kW(electric) of nuclear capital cost can be effectively reduced to ~1500 $/kW(electric) for the hybrid plant. Third, nuclear-assisted NGCC has several advantages over the two single-fuel options in the reduction of high capital costs and high gas prices. In addition, the greenhouse gas emissions can be reduced by half by using nuclear-assisted NGCC, and the amount of nuclear spent fuel per kilowatt-hour would also be less than that of the pure nuclear option.

Regulator selection and endogenous systematic risk

This is the second issue of Wireless Communications and Mobile Computing (WCMC) published by John Wiley & Sons, Ltd. The first issue was published ahead of time and presented some excellent review papers from experts in the field. We received great feedback from a number of colleagues about its content and we promise to continue producing excellent issues in the future. If you did not receive your sample copy of the inaugural issue, please let me or any of the regional editors know to arrange to send you a copy. We have selected seven papers to appear in this second issue. These papers span a good range of topics in the area. The first is a review paper by Ralph and Aghvami. They discuss the Wireless Application Protocol (WAP) architecture and characteristics. Then, they investigate the devices that are supported by WAP as well as the drivers and services. These services include quality of service, security, billing, interoperability, and performance engineering. The variety of media types combined with the diversity of Internet connection characteristics raises momentous challenges to the achievement of ubiquitous access to Internet multimedia content. The second paper, by Margaritidis and Polyzos, addresses issues related to this topic. They identify the importance of adaptation to this category. Then, they examine several important factors that influence the design and optimization of the adaptation architecture. In conclusion, they describe current commercial solutions and future trends in application adaptation in conjunction with recent developments towards wireless access to the Internet. The third paper, by Havinga and Smit, discusses also wireless multimedia networking, but focuses more on energy efficiency. The authors identify three key problems and provide possible solutions to overcome them. The efficient management of power-controlled cellular wireless systems is necessary for their deployment success. Power control can be used as a platform for radio resource management and is important for channel fading as well as providing QoS to individual users. Xiao, Shroff and Chong review the developments of distributed power control and related resource management problems in cellular wireless systems. The discussion is concentrated on achieving high efficiency for a power-controlled system while preventing the system from failure. They then review power and rate control schemes proposed for wireless data, and present a framework for utility-based power control as a possible candidate for distributed power control of multimedia wireless systems. In the fifth paper, Arslan and Bottomley review commonly used approaches to channel estimation. This is necessary in adaptive receiver designs used in narrowband and wireless digital communication systems. They consider both time-invariant and time-varying channels in their discussion. They also provide a number of applications that will make use of this standard. On the other hand, Tepedelenliolu, Abdi, Giannakis and Kaveh talk about estimation of Doppler spread and signal strength in wireless systems. They concentrate on estimating the received signal strength, mobile velocity, and other related statistical channel parameters that apply to handoff and adaptive transmission. They provide comparison of the presented schemes based on their modeling and simulation results. Finally, Annamalai and Tellambura present a research paper discussing three new exponential-type bounds derived using the Cauchy–Schwarz bounding technique. They show that these new bounds are found to be tight and useful for a number of applications. They compare these bounds to other well-known exponential type bounds and prove that these perform at least comparable or tighter. We hope that you will enjoy reading this issue and welcome any comments to any of the four editors listed below. Again, we welcome all of you to contribute and encourage your colleagues and libraries to subscribe to this fine publication.

Markovian jumping systems have arisen naturally in the mathematical modeling of phenomena spanning disciplines in the social sciences, natural sciences, and engineering. This kind of stochastic dynamical systems can be employed to model the dynamics when parameters are subject to random abrupt changes due to sudden environment changes, subsystem switching, system noises, executor faults, and so forth. Much attention has been given to modeling, optimization, and real applications of such stochastic dynamical systems in the literature in recent years. As the advanced control and optimization will provide a basis for the design and application of such stochastic systems, these advanced techniques would result in substantial and sustainable benefits. The accepted papers in this special issue include stochastic stability, stabilization, stochastic control optimization, system modeling and identification methods, predictive control, signal processing, robust filtering, multiagent systems, networked control systems, time-delayed systems, neural networks, the Takagi-Sugeno fuzzy systems, simulated annealing, and fault detection methods.

The calibration of the verification equipment for AC electrical energy meters (hereinafter referred to as the DUT) was being performed manually till now. A new system for remote automatic calibration of the DUT, which applies cloud server, 4G cellular mobile interconnection technology and virtual serial communication technology, was firstly proposed in this paper. The technical problems of remote automatic calibration of large equipment, and safety problems in equipment transportation, wiring and installation were solved by developing automatic test and management software, remote communication management platform, designing and developing remote control device and special connection terminal base.