Showing papers in "IEEE Computer Applications in Power in 1990"
TL;DR: The Electromagnetic Transients Program (EMTP) as discussed by the authors is a general-purpose computer program for simulating high-speed transient effects in electric power systems, which can be used to provide recommendations on equipment characteristics and operating procedures for power line and transformer energization.
Abstract: The development of the Electromagnetic Transients Program (EMTP), a general-purpose computer program for simulating high-speed transient effects in electric power systems, is briefly described. To illustrate the EMTP's capabilities, three examples of its use are presented. As part of the planning activities of the Athabasca Electric System in northern Saskatchewan, Canada, EMTP studies were done to provide recommendations on equipment characteristics and operating procedures for power line and transformer energization. These two studies were performed using the DCG/EPRI EMTP Version 1.0. The third application is to the 2000 MW high voltage direct current (HVDC) link between France and Great Britain. As part of a simulation exercise to check the protection settings and calculate the transient disturbances due to the switching-in of equipment or fault clearing near the station, the converter transformers were modeled using the EMTP saturated transformer model. Comparisons between the simulations and actual field tests are shown for the line energization and transformer switching transients studies. The accuracy of replication of the results is good. >
61Â citations
Journal Article•
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TL;DR: The concept of adaptive relaying, which allows computer relays to monitor themselves and to report their condition to a central location, and various applications, including load effect, cold load pickup, end-of-line protection, transformer protection, and automatic reclosing are explained.
Abstract: The concept of adaptive relaying is explained. The reasons for choosing adaptive relaying are examined, and various applications are described. These include load effect, cold load pickup, end-of-line protection, transformer protection, and automatic reclosing. The tradeoff between dependability and security of protection is discussed. The ability of computer relays to monitor themselves and to report their condition to a central location is also discussed. >
40Â citations
TL;DR: SIMPOW as mentioned in this paper is a digital power system simulator for studies in which the access to realistic models of all established and future electrical equipment such as multiterminal HVDC systems, phasewise-controlled static VAr controllers, superconducting magnetic energy storage, flexible AC transmission systems, and other advanced technologies is essential.
Abstract: A description is given of SIMPOW, a digital power system simulator for studies in which the access to realistic models of all established and future electrical equipment such as multiterminal HVDC systems, phasewise-controlled static VAr controllers, superconducting magnetic energy storage, flexible AC transmission systems, and other advanced technologies is essential. The basic design concept of SIMPOW is examined, covering functional parts, power-frequency models, instantaneous value models, user-defined modeling, man-machine communication, and power-flow solution and integration procedures. Simulation stages and event handling are briefly considered. To illustrate the use of the simulation techniques described, three typical problems to which they have been applied successfully are presented in detail. They are the balancing of traction loads by means of phasewise controlled static VAr controllers, bulk power transmission by a multiterminal HVDC system, and simulation of electrical machine dynamics. Further improvements that are planned for SIMPOW are described. >
39Â citations
TL;DR: The importance of taking power quality considerations into account at the design stage is stressed as mentioned in this paper, and various types of power disturbances are briefly defined, and their causes are examined. Techniques used to mitigate power quality disturbances are reviewed.
Abstract: The various types of power disturbances are briefly defined, and their causes are examined. Techniques used to mitigate power quality disturbances are reviewed. The coordination of protection methods is discussed. The importance of taking power quality considerations into account at the design stage is stressed. >
29Â citations
TL;DR: The offline test results, although preliminary, suggest that the neural network approach is promising in developing a generic intelligent alarm processor that could be implemented by various electric utilities with minimal customization effort.
Abstract: The problem of interpreting a large number of alarms in a power system control center under stress conditions is considered. A description is given of an experiment using a neural network to build and test an intelligent alarm processor, that can analyze the multiple alarms associated with a system problem and identify the particular problem causing the alarms. The offline test results, although preliminary, suggest that the neural network approach is promising in developing a generic intelligent alarm processor that could be implemented by various electric utilities with minimal customization effort. >
24Â citations
TL;DR: In this article, a remote measurement calibration (RMC) methodology is proposed to eliminate installation errors and minimization of the systematic errors by frequent and remote analysis of measurements and instruments and provides the state estimator with unbiased measurements and the actual standard deviation, both of which are necessary for the SE to provide a reliable real-time database.
Abstract: The analog measurements used for state estimation generally include systematic errors introduced by the deviations in gain, zero offset, and nonlinearity of the instruments, random errors caused by the degree of precision of various instruments in the measurement streams, and installation errors due to the use of erroneous instrument ratios, transducer ratings, and scaling procedures. At present, instruments are calibrated on-site every two to three years, a procedure that is unsatisfactory, untimely, and labor intensive. A remote measurement calibration (RMC) methodology that allows elimination of installation errors and minimization of the systematic errors by frequent and remote analysis of measurements and instruments is presented. It provides the state estimator (SE) with unbiased measurements and the actual standard deviation, both of which are necessary for the SE to provide a reliable real-time database. >
21Â citations
TL;DR: In this article, the computed performance of American Electric Power's remotely located 2600 MW Rockport plant after simulated generator loss-of-field (LOF) disturbances to one of its 1300 MW crosscompound units is described.
Abstract: The computed performance of American Electric Power's remotely located 2600 MW Rockport plant after simulated generator loss-of-field (LOF) disturbances to one of its 1300 MW cross-compound units is described. LOF conditions are reviewed, and AEP's experience and practice in dealing with such conditions are examined. The modeling used in the computer simulation analyses is discussed. Two simulation analyses are considered: LOF on a high pressure generator with no prior disturbance and, more briefly, LOF on a reheat turbine generator with no prior disturbance. Studies of potential false operation and plans for future LOF analyses are discussed. >
18Â citations
TL;DR: An overview of an electric distribution management system that can support evolution and flexibility for customers in the 1990s and beyond is provided and the ability to evolve, system integration, and user-focused development are discussed.
Abstract: A system solution approach to information management for electrical distribution that meets the requirements being imposed by industry trends and the electric utility customer is presented. The approach is based on three significant phenomena in the computer industry: the replacement of traditional mainframe computer solutions with networked microcomputer and workstation solutions; the emergence of a standards-based software products industry; and the movement toward object-oriented software methodologies. The resulting technology enables the construction of generalized information systems that can evolve and be augmented over extended life cycles while containing maintenance and lifetime costs. An overview of an electric distribution management system that can support evolution and flexibility for customers in the 1990s and beyond is provided. The ability to evolve, system integration, and user-focused development are discussed. >
17Â citations
TL;DR: In this paper, a method is presented for reproducing in the laboratory actual faults that have occurred in the field and generating worst-case-fault waveshapes for the actual power lines being protected.
Abstract: A method is presented for reproducing in the laboratory actual faults that have occurred in the field and generating worst-case-fault waveshapes for the actual power lines being protected. Digitally reproducing faults or system disturbances that caused undesired or unexplained results in the protection scheme is the key to the method. The faults can then be replayed through amplifiers and applied to the control and protection devices. Changes to settings or logic schemes can be implemented, and field data can be applied to the protection system located in the laboratory. The tested equipment can then be installed in the operating system with a high degree of confidence. >
17Â citations
TL;DR: In this paper, an extension of the finite element technique is described that allows one to find simultaneously the electromagnetic fields, the winding currents, and the rotor motion in order to understand the effect of harmonic current and voltage on large squirrel-cage induction motors.
Abstract: A nonmathematical description of the finite element analysis method is presented. Application of the method to determining the excitation requirement of a large turbine generator is discussed. The handling of short-circuit behavior and end-region fields is considered. An extension of the finite element technique is described that allows one to find simultaneously the electromagnetic fields, the winding currents, and the rotor motion in order to understand the effect of harmonic current and voltage on large squirrel-cage induction motors. >
17Â citations
TL;DR: Consumers Power Company, an investor-owned, combination (gas and electric) utility serving customers throughout most of Michigan's lower peninsula, is in the process of adding a 345/138 kV autotransformer bank, rated 300 MVA self-cooled, to one of its substations.
Abstract: Consumers Power Company, an investor-owned, combination (gas and electric) utility serving customers throughout most of Michigan's lower peninsula, is in the process of adding a 345/138 kV autotransformer bank, rated 300 MVA self-cooled, to one of its substations. Before a system modification of this scale can be completed, protective relay settings throughout the area must be reviewed. Consumers Power Company's experience using the coordination graphics module to review settings for the planned system change and determine new settings to provide the required coordination is reported. The coordination analysis of overcurrent and distance devices is described. >
TL;DR: POSCODAM (power system computation and data management) is an integrated package of three program systems, namely, POSDAM, POSCO, and POSGRAPH, for graphical input and output of network topologies and computed results.
Abstract: Features of POSCODAM, a power system planning and analysis software package, are described. POSCODAM (power system computation and data management) is an integrated package of three program systems, namely, POSDAM (power system data management), POSCO (power system computation), which consists of load-flow and short-circuit analysis modules, and POSGRAPH (power system graph), for graphical input and output of network topologies and computed results. During the past six years, this package has been used for applications such as optimization of energy transmission in regional electric networks, determination of reactive power compensation, investigation of system and equipment overloads, determination of system short-circuit power levels, dimensioning of switchgear and protection coordination, and grounding of power system neutrals. >
TL;DR: A multifunction relay that uses advanced digital electronic design to incorporate most (or all) of the required protection functions into one package and thereby significantly reduce the expense is described.
Abstract: A multifunction relay that uses advanced digital electronic design to incorporate most (or all) of the required protection functions into one package and thereby significantly reduce the expense is described. User requirements and design considerations are examined. The discrete-Fourier-transform-based digital signal processor is discussed. Interprocessor communication and the host processor are briefly considered. >
TL;DR: An unmanned intrusion detection system for power stations or substations that detects trespassers in real time, both indoors and outdoors, and is based on image processing is given.
Abstract: A description is given of an unmanned intrusion detection system for power stations or substations that detects trespassers in real time, both indoors and outdoors, and is based on image processing. The main part of the system consists of a video camera, an image processor, and a microprocessor. Images are input from the video camera to the image processor every 1/60 s, and objects that enter the field of the image are detected by measuring the changes of the intensity level in selected sensor areas. The shapes and locations of active sensor areas can be determined based on detection application, using techniques tailored to the application. Noise removal filters prevent spurious detections. High detection sensitivity is guaranteed under any environmental condition. The system configuration and the detection method are described. Experimental results under a range of environmental conditions are given. >
TL;DR: In this article, the problem of determining which power system parts are still supplied with electric power and which are disconnected after a brownout or blackout, a task that requires a skilled operator and/or sophisticated energy management system functionalities, is addressed.
Abstract: The problem of determining which power system parts are still supplied with electric power and which are disconnected after a brownout or blackout, a task that requires a skilled operator and/or sophisticated energy management system (EMS) functionalities, is addressed. Finding out in a complex power station which feeders are energized may severely burden the user. Getting an overview of whether a certain network is observable, and thus estimated, or is determined based on nontelemetered, unreliable information is usually outside the operator's capabilities. A first implementation of Show It With Colors, which aims at improving the operator's capability to manage the power system by providing information in a more comprehensible form, is described. The discussion covers what is to be shown, priority of information, response time, colors used, updating the colors, bringing the coloring information to the network diagrams, experience with the system, and possible further enhancements. >
TL;DR: A microcomputer program that graphically illustrates steady-state polyphase machine behavior under a variety of balanced and unbalanced operating conditions is described.
Abstract: A microcomputer program that graphically illustrates steady-state polyphase machine behavior under a variety of balanced and unbalanced operating conditions is described. Implemented in the C language, the interactive program employs sophisticated screen color graphics to show the slow-motion progression of the appropriate voltage or current waves, the loci of the resulting magnetic fields, and the movement of the machine rotor. It can be used to illustrate dynamically revolving-field concepts, the use of symmetrical components, and the operation of synchronous and induction machines under conditions of sustained electrical unbalance. The motivation for such a program, its operation, and its capabilities are described. >
TL;DR: The Cable Ampacity Program (CAP), a set of user-friendly routines for IBM or compatible desktop computers is discussed, which includes a user- friendly front-end program, INPUT; a steady-state analysis program, SAMP; a transient analysis program; support files for all programs; and graph programs for display of the steady- state and transient results.
Abstract: The Cable Ampacity Program (CAP), a set of user-friendly routines for IBM or compatible desktop computers is discussed. CAP includes a user-friendly front-end program, INPUT; a steady-state analysis program, SAMP; a transient analysis program, TAMP; support files for all programs; and graph programs for display of the steady-state and transient results. INPUT, SAMP, and TAMP are described. >
TL;DR: In this paper, a system that uses a hardware interface a PC, and advanced software to measure, analyze, and report the condition of the harmonics on the power system is described, which has the ability to measure the distortion on both the voltage and current of the power systems.
Abstract: A system that uses a hardware interface a PC, and advanced software to measure, analyze, and report the condition of the harmonics on the power system is described. It has the ability to measure the distortion on both the voltage and current of the power system. Following a review of harmonic characteristics, the measurement techniques, data acquisition, analyses and report generation, and use of the information are discussed. The system has greatly reduced the effort needed for a study. >
TL;DR: A hardware and software system for variable spot pricing that is in service in 550 homes is discussed and future directions for this technology are identified, including both technical advances required and additional applications for such a system.
Abstract: A hardware and software system for variable spot pricing (VSP) that is in service in 550 homes is discussed. Its basic functions and implementation strategies are examined. The system manager, a wide-area communication network for timely and reliable communications between the system manager and the customer equipment, and customer premises equipment are described. Future directions for this technology are identified, including both technical advances required and additional applications for such a system. >
TL;DR: A real-time AC power system simulation laboratory that has been developed at Arizona State University is described, which gives students the opportunity to witness first-hand how a large power system behaves.
Abstract: A real-time AC power system simulation laboratory that has been developed at Arizona State University is described. The laboratory gives students the opportunity to witness first-hand how a large power system behaves. It can simulate scenarios to demonstrate system disturbances of various types as well as appropriate recovery actions. Researchers also use the laboratory to study power system control methods, effects of various models and algorithms in the simulation, the effectiveness of full graphic displays, and computer communication methods. An overview is given of the computational environment, which consists of three major types of software running concurrently on two computers. The operation of the system is demonstrated for a simple scenario, i.e. relieving an overloaded transformer or line. >
TL;DR: The automation of the transmission and distribution (TD automation of load tap changer controls; control sequences, particularly for voltage reduction and emergency load curtailment; emergency isolation of network grids; and TWACS) was discussed in this paper.
Abstract: Advances in the automation of the transmission and distribution (TD automation of load tap changer controls; control sequences, particularly for voltage reduction and emergency load curtailment; emergency isolation of network grids; and TWACS. >
TL;DR: The use of postanalysis at Southern Company Services, Inc. (SCS) to compare systematically the actual pool dispatch against the ideally planned strategy is discussed in this paper, which has proved to be very effective in raising the cost awareness among system dispatchers and sharpening their intuitive knowledge of the overall system economics.
Abstract: The use of postanalysis at Southern Company Services, Inc. (SCS) to compare systematically the actual pool dispatch against the ideally planned strategy is discussed. The post-analysis report, which is generated each morning by the operations planning department, provides system schedules with concrete feedback on how well the system was dispatched the previous day. The practice has proved to be very effective in raising the cost awareness among system dispatchers and sharpening their intuitive knowledge of the overall system economics. The software tools that are used at SCS to perform postanalysis are described, and two case studies are presented to illustrate the use of these tools in a day-to-day operating environment. >
TL;DR: The evolution in user-machine interfaces for power system network analysis software is examined, and an interactive graphics approach is described, which appears as a single entity rather than a collection of different modules.
Abstract: The evolution in user-machine interfaces for power system network analysis software is examined, and an interactive graphics approach is described. Batch and interactive processing are defined, and the drawbacks of text-based interactive interfaces are identified. The development of a user-machine interface for power system network analysis using interactive graphics is described. The conceptual model used to visualize the power system is the one-line diagram. The task of modifying the network and the task of editing the one-line diagram are combined into a single task. The use of command modes in the program was avoided by supporting the full range of commands at all times. From the user's perspective, the program appears as a single entity rather than a collection of different modules. >
TL;DR: An overview is given of the load management system started by Florida Power Corporation in 1981 to defer 825 MW of additional peaking capacity needed by January of 1995, a volunteer program with over 260000 residential customers presently participating and 40000 customers being added each year.
Abstract: An overview is given of the load management system started by Florida Power Corporation (FPC) in 1981 to defer 825 MW of additional peaking capacity needed by January of 1995. It is a volunteer program with over 260000 residential customers presently participating and 40000 customers being added each year. These customers allow FPC to interrupt selected appliances in return for a credit on their electric bills. The load management controller consists of dual-redundant HP-1000 computers, each with a dedicated terminal and keyboard, 20 Mbyte hard disk, and 5.25 in floppy disk drive. They run identical software and are loaded with the same database. The load management database resides on the corporate mainframe computer. FPC is in the initial phases of specifying a new controller that will be able to communicate with the Energy Control Center computer system. An expert system in the new controller will be able to develop strategies on short notice to conform to changing operating conditions. >
TL;DR: In this article, a computer program that considers all propagation paths that sound can take to travel from source to receivers (including reflections on barriers and ground, diffraction around barriers, transmission through barriers, etc.) is described.
Abstract: A computer program that considers all propagation paths that sound can take to travel from source to receivers (including reflections on barriers and ground, diffraction around barriers, transmission through barriers, etc.) is described. It is available on a PC to help the substation designer estimate the contours of noise levels resulting from a selected substation layout. The sources of the audible noise generated by substation power transformers are identified, and a qualitative overview of the physics of sound propagation is given. The method of calculation used by the program and the kind of input required are discussed. >
TL;DR: In this paper, an online method of determining a unit's economic characteristics, developed under EPRI's Power Plant Performance Instrumentation System Project (RP 1681/2153), is discussed.
Abstract: An online method of determining a unit's economic characteristics, developed under EPRI's Power Plant Performance Instrumentation System Project (RP 1681/2153), is discussed. The method, called the Incremental Heat Rate Monitor, will soon be available as part of EPRI's Plant Monitoring Workstation (PMW). The PMW and the role of the monitor within it are described. Essentially, the monitor constructs the input/output and incremental heat rate curves periodically, at 15-min intervals for example, so the information that is used for economic dispatch need never be out of date. Further, the monitor accurately reflects the true condition of the unit including the influence of valve loops and the switching of large auxiliaries. >
TL;DR: A description is given of the design, integration, and implementation of an energy management system by Electricidade de Portugal (EDP), using some nontraditional methods that provided a high degree of collaboration, efficiency, and flexibility.
Abstract: A description is given of the design, integration, and implementation of an energy management system (EMS) by Electricidade de Portugal (EDP), using some nontraditional methods that provided a high degree of collaboration, efficiency, and flexibility. EDP power characteristics, optimal meter placement, and the performance of automatic generation control in the presence of low-baud-rate communications were considered early in the design process. EDP's system architecture was also considered in overall EMS design. The key to efficient implementation was to separate, distribute, and execute simultaneously as many of the time-consuming tasks as possible. >
TL;DR: In the early 1980s, diversification in energy sources, reduction in the price differential between gas and oil, and area security constraints made the process of selecting the most economical energy mix at Florida Power & Light (FPL) Co. too complex for the operator to evaluate using the standard unit commitment program as mentioned in this paper.
Abstract: In the early 1980s, diversification in energy sources, reduction in the price differential between gas and oil, and area security constraints made the process of selecting the most economical energy mix at Florida Power & Light (FPL) Co. too complex for the operator to evaluate using the standard unit commitment program. This prompted FPL to develop an extensive unit commitment program that accounts for and optimizes external power purchases and gas-oil allocation-schedules, while accounting for area security constraints (transmission and generation), gas transmission constraints, FPL unit availability, and other operating constraints. FPL's unit availability, and other operating constraints. FPL's experience with the program in an operating environment is recounted. A description of the enhancements and the reasons for them is given, and an economic evaluation of the extensive unit commitment program is presented. >
TL;DR: A valve monitoring system that enables the selection of power plant steam and containment valves to be serviced to be made on a justifiable priority-of-need basis is described in this article.
Abstract: A valve monitoring system that enables the selection of power plant steam and containment valves to be serviced to be made on a justifiable priority-of-need basis is described. The system is designed to assist utilities in increasing plant availability and in decreasing maintenance costs attributed to valving. The system operates in one of two modes: trending or single-stroke. In the trending mode, the system monitors the performance of critical valves while the plant is online and compares sensor data with baseline signatures. Deviations from baseline data are evaluated by an expert system, and when the deviations exceed caution levels, probable causes of trouble are identified. In the single-stroke mode, the system is hooked up to any valve when the plant is offline and the valve is cycled through one full stroke (opening and closing). Using engineering data for the valve, the sensor signals are analyzed and a diagnosis is made. >
TL;DR: The problems encountered in transferring the technology of external R&D projects on the energy management systems at Niagara Mohawk Power Corporation are addressed and an attempt is made to define the requirements for an interface, eliminating the recurring need for modifying the EMS software to accommodate external products.
Abstract: The problems encountered in transferring the technology of external R&D projects on the energy management systems (EMS) at Niagara Mohawk Power Corporation are addressed. The need for a general-purpose external applications support interface to an EMS is argued, and an attempt is made to define the requirements for such an interface, eliminating the recurring need for modifying the EMS software to accommodate external products. The interface would provide transparent access to external applications by the EMS and vice versa as well as the ability to initiate program execution in the peer system. The transparency of access encompasses transparency of data location, data structure, and data organization. These objectives suggest the possibility of a two-component interface, where the communications component handles request and data interpretation. >