Showing papers in "IEEE Computer Applications in Power in 1996"
TL;DR: In this paper, the authors proposed intervention by computer-based rational control schemes to reduce or eliminate the likelihood of the hidden failure of key relays in traditional relaying systems, where relays with high-vulnerability indices can be identified and their vulnerable functions and failure modes identified.
Abstract: Major blackouts are rare events, but their impact can be catastrophic. A study of significant disturbances reported by NERC in the period from 1984 through 1988 indicates that protective relays are involved in one way or another in 75 percent of major disturbances. A common scenario is that the relay has an undetected (hidden) defect that was exposed due to the conditions created by other disturbances. For example, nearby faults, overloads, or reverse power flows expose the defective relay and cause a false trip, which exacerbates the situation. Given the importance of hidden failure modes in traditional relaying systems, intervention by computer-based rational control schemes is proposed in this article. Relays with high-vulnerability indices can be identified, and their vulnerable functions and failure modes identified. Countermeasures to reduce or eliminate the likelihood of the hidden failure of key relays can be provided.
237 citations
TL;DR: Here, the authors describe how wavelets may be used in the analysis of power system transients using computer implementation.
Abstract: Wavelets are a recently developed mathematical tool for signal analysis. Informally, a wavelet is a short-term duration wave. Wavelets are used as a kernel function in an integral transform, much in the same way that sines and cosines are used in Fourier analysis or the Walsh functions in Walsh analysis. To date, the primary application of wavelets has been in the areas of signal processing, image compression, subband coding, medical imaging, data compression, seismic studies, denoising data, computer vision and sound synthesis. Here, the authors describe how wavelets may be used in the analysis of power system transients using computer implementation.
142 citations
TL;DR: How a neural network, trained to recognize patterns of transmission line faults, has been incorporated in a PC-based system that analyzes data files from substation digital fault recorders is described.
Abstract: The analysis of transmission line faults is essential to the proper performance of a power system. It is required if protective relays are to take appropriate action and in monitoring the performance of relays, circuit breakers and other protective and control elements. The detection and classification of transmission line faults is a fundamental component of such fault analysis. Here, the authors describe how a neural network, trained to recognize patterns of transmission line faults, has been incorporated in a PC-based system that analyzes data files from substation digital fault recorders.
112 citations
TL;DR: In this article, the authors developed an adaptive, intelligent, monitoring system for large power transformers, and four large transformers on the Boston Edison system are under continuous surveillance by this system, which can summon attention to anomalous operation through paging devices.
Abstract: Massachusetts Institute of Technology (MIT) has developed an adaptive, intelligent, monitoring system for large power transformers. Four large transformers on the Boston Edison system are under continuous surveillance by this system, which can summon attention to anomalous operation through paging devices. The monitoring system offers two advantages over more traditional (not adaptive) methods of tracking transformer operation: while temperature measurements have been made for some time and can even be incorporated into SCADA systems, comparison of actual measurements with predictions based on operating conditions and ambient temperature can provide a much more sensitive measure of actual transformer condition; and while oil samples are taken from transformers and analyzed for chemical species that might indicate abnormal operation, continuous monitoring of oil chemistry can give immediate indication of something going wrong, perhaps in time to remove the transformer from service and prevent a catastrophic failure. The authors describe the monitoring system and field experience.
64 citations
TL;DR: In this paper, the authors describe how, with modern computer programs, a thorough study of power system oscillatory stability is possible, and the necessary complex mathematics are made transparent to the program user.
Abstract: Power systems are among the most complex dynamic systems created by man, and the insidious nature of oscillatory instability has mystified many practicing engineers. The author describes how, with modern computer programs, a thorough study of power system oscillatory stability is possible. The necessary complex mathematics are made transparent to the program user, and the emphasis of studies may be placed on the physical nature of the oscillatory phenomena and the accuracy of the model data. Careful control design and consistent control commissioning and tuning are required to damp power system oscillations sufficiently so that system operating limits are caused by other phenomena.
61 citations
TL;DR: In this paper, the authors focus on the selection and application of optimization methods for distribution design, including numerical optimisation (both nontransshipment and transshipment), genetic algorithms, and null point load flow.
Abstract: In order to determine the design of a distribution system a planner must determine three aspects of design simultaneously: layout (the manner in which the distribution pathways are split and resplit on their way from a few sources, or substation buses, to many customers), line size (the selection of conductor size, number of phases, and line type for each segment), and radial switching pattern (determining the normally open points within the network that force an electrical flow into a radial pattern). These three aspects of design interact heavily with one another, and generally the true least-cost plan can be found only by considering all three simultaneously. In most real-world situations, the number of possible combinations of layout, line sizing, and switching is so large that the probability of a smart, experienced engineer finding the very best configuration unaided is rather remote. Optimization methods that analyze all three aspects simultaneously to minimize cost can provide a real benefit. But no optimization method encompasses all aspects of distribution design, and no method is completely free of approximations and limitations. They are merely tools that can provide great help in distribution design if properly applied. Their good performance depends on proper selection and fitting to the problem and engineering CAD environment. This article focuses on selection and application of optimization methods for distribution design. The methods are numerical optimisation (both nontransshipment and transshipment), genetic algorithms, and null point load flow.
53 citations
TL;DR: In this paper, the authors present Pacific Gas and Electric Company's (USA) approach to utilizing the existing infrastructures and available data more effectively by introducing intelligence to DA/SCADA systems through development of advanced analytical tools for operations decision support.
Abstract: In the past 10 years, the electric power industry's involvement in distribution automation (DA) has been principally focused on remote monitoring and control of the distribution systems and their equipment. SCADA has constituted the most significant attribute. Electric utilities in many locations around the world have installed numerous SCADA systems for their distribution substations and feeders and built the infrastructure for real-time distribution operation and control. Real-time data is available to human operators, enabling them to monitor more and more events in their distribution systems and to control automatic equipment remotely. This article features Pacific Gas and Electric Company's (USA) approach to utilizing the existing infrastructures and available data more effectively by introducing intelligence to DA/SCADA systems through development of advanced analytical tools for operations decision support.
44 citations
TL;DR: In this article, the authors describe a voltage sag analysis program, developed by Power Technologies, Inc. The program uses methodologies developed for the update of the IEEE Gold Book (IEEE Standard 493, Recommended Practice for the Design of Reliable industrial and Commercial Power Systems).
Abstract: Voltage sags are momentary dips in voltage that may cause misoperations to the electric utility customers' sensitive loads. These misoperations may only be an annoyance to the residential sector, but, on the industrial and commercial front, they can cost millions of dollars each year. It is impossible to eliminate all of these faults and associated voltage sags, but an improvement can be achieved through power system modifications on both the utility system and the industrial or commercial power system. The evaluation of these system modifications was difficult in the past, but the authors describe a voltage sag analysis program, developed by Power Technologies, Inc., which has simplified the task. The program uses methodologies developed for the update of the IEEE Gold Book (IEEE Standard 493, Recommended Practice for the Design of Reliable industrial and Commercial Power Systems). The results of this sag analysis program form the basis of possible future cost-benefit analysis enabling electric utilities and utility customers to make the most economic system modification.
41 citations
TL;DR: In this paper, the authors argue that such analysis of costs and cost flow will become as routine and sophisticated as the analysis of electrical performance is at the present, and they also argue that this analysis should be made available to the transmission system operators, regardless of the precise nature of the deregulated system's rules and structure, so that they can know the actual operating costs of providing transmission services to their customers.
Abstract: A central tenet of electric power industry deregulation is that the delivery of electric power (a service) must be decoupled from the purchase of the power itself (a product) and priced and contracted separately. Transmission of electricity must be offered and priced separately from the power itself, and delivery of power must stand on its own as a business. Regardless of the precise nature of the deregulated system's rules and structure, this means that transmission system operators need to know the actual operating costs of providing transmission services to their customers. Here, the authors argue that such analysis of costs and cost flow will become as routine and sophisticated as the analysis of electrical performance is at the present.
39 citations
TL;DR: A restructuring of the electric power business in the United States is under way as mentioned in this paper, which will shift the industry focus from local, vertically integrated monopolies to regional, competitive, and unbundled corporate structures.
Abstract: A restructuring of the electric power business in the United States is under way. The form of the restructuring will shift the industry focus from local, vertically integrated monopolies to regional, competitive, and unbundled corporate structures. The premise for change is that market imperfections occur under the regulated monopolistic structure, leading to inefficient use of the interconnected transmission and generation systems. The new order, generically called POOLCO, will not require any fundamentally new analytical system planning methods. It will, however, require the merging of existing generation and transmission (G&T) software into a new G&T system planning function. POOLCO will also require development of new accounting software and communications media.
35 citations
TL;DR: The content of the industry reports and the FERC rulings are outlined, which provide a low-cost, high-function, consistent interconnected network to provide information to all transmission customers.
Abstract: On March 29, 1995, the US Federal Energy Regulatory Commission (FERC) issued a notice of proposed rulemaking (NOPR) aimed at promoting wholesale competition through nondiscriminatory open transmission access. Industry working groups were formed to define the content of the transmission services information to be communicated over an electronic network and to define the requirements of the network itself. FERC issued final rules on April 24, 1996. At this writing, the transmission services information network (TSIN) is just completing design, and initial implementation should be in place by November 1, 1996. There will be about 2035 nodes representing all public transmission systems in the United States. The network will use the Internet as a base, allowing access by all authorized users anywhere in the world. The tools used will be based on the standard Internet tools such as World-Wide Web browsers. This provides a low-cost, high-function, consistent interconnected network to provide information to all transmission customers. The network will have good performance and be secure. It will allow transmission customers to have information on available transmission capacity, costs and tariffs for transmission capacity and costs of ancillary services. This article outlines the content of the industry reports and the FERC rulings.
TL;DR: In this paper, the authors describe how, with the aid of a network of electromagnetic sensors, computer systems, and satellite communications, the National Lightning Detection Network can now help electric utilities prepare for storms.
Abstract: Based on an extensive survey of US electric utilities, lightning is the single largest cause of outages on distribution and transmission systems in lightning-prone areas. Here, the authors describe how, with the aid of a network of electromagnetic sensors, computer systems, and satellite communications, the National Lightning Detection Network can now help electric utilities prepare for storms. Tools to track thunderstorms for advance warning thus enable utilities to reduce damage and shorten repair time.
TL;DR: The methodology is based on the use of satellite images of the geographic region which the transmission line will cross and searches for the most economical alternative and the one with the least environmental impact within the area of concern.
Abstract: The process of selecting an optimal route for a transmission line is complex as it involves technical, social, economic, environmental, and planning aspects. A new method was developed to help engineers select routes of specific transmission lines. The methodology is based on the use of satellite images of the geographic region which the line will cross. The selection process searches for the most economical alternative and the one with the least environmental impact within the area of concern. This is achieved by using an image recognition software package and a program that uses minimal path techniques with support of weight restrictions. This article defines the methodology and uses a region of Mexico as an example to illustrate the optimal route selection process.
TL;DR: In this paper, the authors describe a technique by which asset exposure locations and lightning-caused disturbances can be pinpointed by combining accurate power transmission line asset location with lightning timing and location.
Abstract: The authors describe a technique by which asset exposure locations and lightning-caused disturbances can be pinpointed by combining accurate power transmission line asset location with lightning timing and location.
TL;DR: In this article, the use of a phasor measurement unit, a microprocessor based data acquisition system and signal processing platform with an integral GPS clock and multiple inputs, is described.
Abstract: The ability to perform power system measurements synchronously over large areas opens a new window on dynamics occurring within the power system. A number of events were recorded by GPS satellite-locked disturbance recorders, and the records illustrate the frequency variation that exists across a network during transients, the swinging of various points in the system with respect to each other during a disturbance, and the effects of loss of generation or load over extremely long distances. Measurements are made possible by the use of embedded computers and digital signal processing technology. The author discusses the use of phasor measurement unit, a microprocessor based data acquisition system and signal processing platform with an integral GPS clock and multiple inputs. The system allows more accurate recording of power system phenomena that would otherwise remain undetected. System response data permits the validation of models, real-time measurement of protection characteristics, and early detection of potential system instabilities or equipment malfunction.
TL;DR: In this article, an attempt at simulating a remote cranking operation for the black start of two coal-fired drum-type power generation units at Northern States Power Company, USA is described.
Abstract: This article describes an attempt at simulating a remote cranking operation for the black start of two coal-fired drum-type power generation units at Northern States Power Company, USA. The simulation system uses power flow and generator reactive capability programs in an iterative process to determine the appropriate tap positions for the combustion turbine (CT) unit and auxiliary transformers, the various transformers installed in the steam power plant path, and for controlling a proper voltage level for the generator system bus at the CT plant.
TL;DR: The evolutionary growth in the use and application of microprocessors in substations has brought the industry to the point of considering integrated substation protection, control and monitoring systems as mentioned in this paper.
Abstract: The evolutionary growth in the use and application of microprocessors in substations has brought the industry to the point of considering integrated substation protection, control and monitoring systems. An integrated system holds the promise of greatly reducing the design, documentation, and implementation cost for the substation control, protection, and monitoring systems. Here, the author explains how, before considering the promises, on should consider the technical development path and the present implementation problems.
TL;DR: In this article, the authors describe how, in January 1993, Lakeland Electric and Water (LEW) took on the design and construction of a new 12.47 kV automated distribution system for the Publix Supermarket industrial complex.
Abstract: The authors describe how, in January 1993, Lakeland Electric and Water (LEW) took on the design and construction of a new 12.47 kV automated distribution system for the Publix Supermarket industrial complex. The industrial complex in Lakeland, Florida, USA, totals 2 million square feet and houses a dairy processing plant, bakery, produce plant, delicatessen plant, data processing facility for Publix's entire retail network, purchasing department, as well as several maintenance facilities. The retail chain is LEW's largest customer with a peak demand of 15.5 MW and a load factor of 81%.
TL;DR: In this article, the authors take a look at the reasons why integrated network management is needed, describes aspects of the integration process and the expert system, and points out the most significant elements that make use of internationally accepted standards.
Abstract: Rapid technological advances within the telecommunication sector and the power sector's ever-increasing needs for information and transmission services have led electric utilities to use heterogeneous telecommunication networks, grouping together equipment from various manufacturers and technologies. Management of such networks is difficult and fragmented, often employing proprietary systems. This article takes a look at the reasons why integrated network management is needed, describes aspects of the integration process and the expert system, and points out the most significant elements that make use of internationally accepted standards.
TL;DR: In this paper, the authors present the plan and implementation of the Scarborough Public Utilities Commission (USA) backbone system, which can help electric utilities redesign business environments, add value to existing products and services, and introduce new possibilities.
Abstract: An effective fiberoptic broadband solution can help electric utilities redesign business environments, add value to existing products and services, and introduce new possibilities. Such a communication system, linking a whole enterprise, requires an effective infrastructure backbone on which other suitable technologies may be integrated. This article reviews the plan and implementation of the Scarborough Public Utilities Commission (USA) backbone system.
TL;DR: V-PRO II is a second generation program that is Windows-based that is an excellent training tool for new engineers and contains an extensive protective device library and an interactive on-line diagram for direct data entry.
Abstract: Distribution, substation, and plant engineers can benefit from using an overcurrent protection program in commercial, industrial, and utility applications to aid in clearing temporary faults and isolating permanent faults. In the time it normally takes to check one coordination scheme manually, dozens of alternatives can be evaluated using a graphics-oriented program, because the engineer receives immediate feedback for quick decision-making. It is well known that accurately coordinating overcurrent protection devices can minimize or prevent equipment damage, and electrical power service to customers can be greatly improved. In addition to assisting experienced engineers, an overcurrent protection program is an excellent training tool for new engineers. One such tool, V-PRO II, is a second generation program that is Windows-based. An extensive protective device library and an interactive on-line diagram for direct data entry are key new features. Easily identifiable icons are used along with pop-up menus and dialog boxes to simplify command selection. HELP can be accessed any time, and information on a specific topic can be retrieved quickly using hypertext. The program contains two separate windows: a one-line diagram with symbols for buses, lines, components, and protection equipment; and a time-current worksheet with time-current characteristic curves for both phase and ground coordination.
TL;DR: In this article, the authors present a conceptual specification for the control center energy management systems (EMS) network security applications as a function of the current and expected changes in the electric supply industry.
Abstract: Changes facing the electricity supply industry are significant, and the challenges these changes pose are enormous. There are major changes to the business environment of traditional electric utilities. There are also changes in the management of the companies in that nontechnical people are taking over the leadership of traditionally technical companies to deal with the new business scenario. This raises the concern that there may be a lack of familiarity by management of the technical issues involved with the result that the quality of the product may be at risk over the long term. This article deals with the future. It describes a vision for the control center energy management systems (EMS) network security applications as a function of the current and expected changes in the electric supply industry. The objective is to present a conceptual specification. It suggests possible approaches to the problems control centers are likely to encounter in the future. This future is not far away, the thoughts and recommendations put forth should be largely in place 2 to 3 years from now, if security applications are to serve the emerging industry effectively. One of the objectives of this article is to raise the profile of some of the technical issues and promote better understanding.
TL;DR: In this article, the authors describe how digital simulators present a new development tool for real-time simulation techniques and for the automation of protective relay testing, which is used to meet the testing requirements of power system protection relays.
Abstract: This article looks at the various applications of digital simulator technology that have been used to meet the testing requirements of today's more advanced power system protection relays. The authors describe how digital simulators present a new development tool for real-time simulation techniques and for the automation of protective relay testing.
TL;DR: In this paper, the reliability of the interconnected electric systems in the United States will be impacted by these changes, and the authors examine whether disorder can be avoided in this rapidly changing environment.
Abstract: Electric power transmission access is being opened and many interested parties want to get in on the act. The world of interchange scheduling is now a mixture of both old and new players, with changing rules, and uncertain risks to electric system reliability. Reliable electric system operation requires rigorous discipline in executing interchange schedules. Here, the author examines: whether disorder can be avoided in this rapidly changing environment; and how the reliability of the interconnected electric systems in the United States will be impacted by these changes.
TL;DR: How modular digital simulator configurations range from low-cost single-user, to multiuser environments for open-loop testing and real-time application is described.
Abstract: Digital power system simulators for protective relay testing were introduced as a concept in the late 1970s with the first designs made available in the early 1980s. Since that time, a variety of digital simulator solutions have been implemented and used by utilities, universities, and relay vendors. It is interesting to note that all of the designs had quite different implementation approaches and performance characteristics. This article features a new concept for a modular digital simulator design in which a variety of hardware and software modules have been developed and used to configure different simulator solutions. The author describes how modular digital simulator configurations range from low-cost single-user, to multiuser environments for open-loop testing and real-time application.
TL;DR: In this paper, the authors describe the use of computer systems in such power system modelling applications and present a suitable means of representing network elements and complete network components across the entire frequency range under investigation for the various circuit configurations.
Abstract: With the increasing use of controlled power electronic devices, the computer-aided estimation of future harmonic loads is playing an increasingly important role in the planning of power network expansion projects and in the connection of new loads. A suitable means of representing network elements and complete network components across the entire frequency range under investigation is required for the various circuit configurations. This is necessary in order to conduct investigations of this nature and to achieve realistic results within a reasonable time period. Here, the authors describes the use of computer systems in such power system modelling applications.
TL;DR: The system featured in this article has been developed and commercialized for direct digital modulating control prior to the programmable controller, and the use of input frames containing control block diagrams, which are constructed from several standard operational elements.
Abstract: Software development and maintenance costs continue to decrease as recent graphical user-interface (GUI) techniques advance. Improvement in the hardware cost-performance has also supported GUI success. In the area of modulating control for power plants, however, cost decreases have already been achieved through user-friendly forms. In the area of programmable logic controllers, there are three types of programming methods: relay ladder logic, Boolean, and high level language. Recently, the development of a programmable logic controller with the latest fashioned user interface (such as the window, icon, menu, and pointer environment on a control engineering workstation) has come on the market. Although its GUI features are quite good, it is not easy for plant engineers to use due to the various programming forms (e.g. ladder logic diagrams) which are often used. The system featured in this article has been developed and commercialized for direct digital modulating control prior to the programmable controller. The construction and maintenance tools for the system are set up in workstations and personal computers. The tool is familiar to instrument and control designers and has more GUI uses. The key to the design of this system, however, is the use of input frames containing control block diagrams, which are constructed from several standard operational elements.
TL;DR: A client-server implementation was launched at Tennessee Valley Authority in 1994 to meet the utility's operational-planning needs and some of the lessons learned are summarized and future development plans are outlined.
Abstract: Utilities must be able to develop IT tools fast enough to address today's emerging business needs, such as open transmission access, real-time pricing, etc. This article describes a client-server implementation launched at Tennessee Valley Authority (TVA) in 1994 to meet the utility's operational-planning needs. The article summarises some of the lessons learned and outlines future development plans.
TL;DR: How DrawBase is an acquisition database package that enables such collection and management of technical and statistical information required for distribution system analysis is described.
Abstract: To develop future automation schemes for the control, planning, and operation monitoring functions of an entire electric distribution system, it is necessary to build a database containing voluminous technical and statistical data. Such a database includes relevant values required to perform control in real-time and extended real-time and to carry out the functions of operation planning and statistical analyses. Here, the authors describe how DrawBase is an acquisition database package that enables such collection and management of technical and statistical information required for distribution system analysis.
KEMA1
TL;DR: This article highlights the results of Phase I of the European utility communications architecture (EurUCA), which included analysis of business processes and data flows, assessment of existing standards, specification of architecture standards, and definition of the demonstration phase of the project.
Abstract: Electric utilities all over the world are facing the need for computer system integration to reduce life-cycle cost and enhance flexibility in operation and services. Along with integration of different kinds of data traffic (control, administrative, financial, graphics, etc.), there is a trend toward network computing and sharing of data between increasingly dispersed business offices and computer systems. Development and application of standards are necessary for computer system integration in order to provide connectivity, interoperability for systems, portability, and compatibility for modules. The European utility communications architecture (EurUCA) project aims to contribute to standardization by means of a communication architecture specific to electric utilities in Europe. This article highlights the results of Phase I of the project, which included analysis of business processes and data flows, assessment of existing standards, specification of architecture standards, and definition of the demonstration phase of the project.