One-line Diagram Research Articles

A Software Package for Power System Representation and Simulation

This paper is concerned with the development of a software package for graphical representation and simulation of a power system on PC/AT platform without using MOUSE driven routines. The package permits graphical construction, modification and storage of power system diagram, and allows the results to be displayed on the one-line diagram at appropriate locations.

An object based graphical user interface for power systems

Object-based graphical user interfaces (GUIs) that may be used as flexible, device independent front-ends for power system simulation and control are discussed. An experimental prototype GUI suitable for energy management systems or operator training simulators is described. The GUI is based on the X window environment and uses multiple windows to display differing views of the system and direct mouse manipulations to affect the various power system objects in a consistent fashion. An editing portion of the system allows the dynamic construction of one-line diagrams, although an advanced automatic display generation feature capable of constructing layouts based on database information and sophisticated routing and layout heuristics is also provided. The X window (and C) basis of the implementation of the system provides for its relative platform and operating system independence, and allows the networked operation of multiple platforms running the same functions. The aim of this study is to document the generic features and advantages of such a GUI. >

Guiding a power system restoration with an expert system

Minimizing the amount of time needed to restore a power system helps reduce the economic cost and the public's resentment over the interruption of service. An expert system can help the operator achieve this goal by providing actualized restoration plans, dependable recommendations, and a clear picture of the situation. A hierarchical structure has been adopted for the prototype expert system described. This structure separates the selection of the next objective (strategic reasoning) from the development of a plan showing how this objective can be achieved (tactical reasoning). This separation enables the system to quickly adapt its recommendations when a problem arises during the restoration. Planning connection paths through substations of widely different configurations is greatly facilitated by the adoption of a hierarchical description of the topology of these substations. This knowledge representation scheme is the symbolic equivalent of the one-line diagrams used by the operators.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

An analytical technique to evaluate station one-line diagrams in a network context

A technique is presented for analyzing station one-line diagrams from the point of view of their impact on the entire power network. In order to quantitatively and systematically evaluate alternative station layouts, including their impact on the overall transmission network, and to ensure that all design and operating criteria are addressed, a computer program called the Stations/Network Analysis Package (SNAP) was developed. A description is provided of how the approach was used to evaluate the arrangement of two stations in the Ontario Hydro system.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Interactive graphics interface for power system network analysis

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. >

A real time power system simulation laboratory environment

A laboratory environment for research, teaching and demonstration of power system behavior developed at Arizona State University is described. The main driver is a real-time digital simulation of a large power system. A full-graphic human interface made up of several levels of one-line diagrams, tables and other displays permits the observation of the power system behavior in real time; it also makes it possible to affect its behavior by introducing supervisory control actions. These programs operate on a database, which can be changed to represent different power systems. The simulation and the database are run on a VAX 11-785 mainframe computer, while the human interface is run on an Apollo DN570 workstation with a 19-inch full-graphic color display. The two computers are linked via a high-speed Ethernet data link. The program-to-program communication was specifically developed for this application. The total environment created is that of a power system control center. It can be used to demonstrate and teach power system behavior as well as to experiment with all facets of the energy management system. >

Sample system for three-phase short circuit calculations

The development of short-circuit programs and their use on nuclear electric power systems require that the program results be compared against hand calculations or another proven program. A comparison is given of the results of different types of network solutions for a sample one-line diagram and the corresponding data. The purpose is to provide a sample short-circuit program input-output and a range of solution variance for different numerical methods currently being used by contributors of alternate solutions.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The Electrical Aspects of Cogeneration System Design

Cogeneration and the reasons that it is a viable industry today are discussed. Both bottoming and topping cycles may be employed for cogeneration; however, the topping cycle is the major focus of current cogeneration projects due to its applicability in large cogeneration power plants. The effect and reasons for the Public Utility Regulatory Policies Act removal of many of the disincentives of cogeneration are discussed. The relative efficiencies of conventional and combined-cycle cogeneration power plants are compared in a typical example of a large cogeneration power plant currently under construction. Many considerations face the electrical engineer in the design of a cogeneration power plant. Many applications will be found in industrial plants and will utilize industrial thinking within the plant; however, many decisions will be influenced by conventional electric utility thinking, due to the interface with the electric utility in the switchyard. Basic discussion of the considerations required of the electrical engineer, including electrical system arrangement, integration of the new generation into the plant electrical system, short-circuit matters, one-line diagrams, generator characteristics, excitation systems, step-up transformer ratings and characteristics, auxiliary transformers (station service), distribution systems, and system grounding, is given for preliminary guidance in design.

Graphics Aided Interactive Analysis of Radial Distribution Networks

This paper presents an interactive graphics package for distribution system analysis. The radial operation of the distribution networks is exploited in order to effect a fast and accurate calculation of the power flows, the voltage drops and the power losses at the various segments of a feeder for a given set of typical load curves. The algorithms developed are based on an efficient method to store the network topology and can easily accommodate changes in the infeeding nodes and variations in the network structure due to switching operations. The interactive environment allows the user to obtain the results of his studies against the one-line diagram of the network and effect changes in it in basically diagrammatic terms. The package requires very modest computer resources and provides planning and operating engineers with a powerful tool to conduct analytical distribution system studies with ease and flexibility.

Automatic Generation of Power System One-line Diagrams

Summary An algorithm for automatic generation of power system one-line diagrams is presented. The developed software provides a plot of the one line diagram with insertion of the results of a load flow study. Several features of the one-line diagram generation process have been automated viz. positioning of buses ensuring uniform distribution of buses while retaining relative geographic locations, calculating the length of bus to be drawn based on the number of interconnecting branches, the orientation of the bus being decided depending on the incident angle of the interconnections. Arrangement of these interconnections onto the bus is done by using a sorted order of branches which ensures minimum line crossings. Power System elements such as lines, transformers, generators and loads are represented by appropriate symbols on the diagram. Results displayed include bus names, bus voltages and angles, generation, load and line flows.

The Development of a High Reliability Auxiliary Power System for a Coal-Fired Cycling Generating Station

An auxiliary system for a fossil generating station is evolved based on operating and reliability criteria including the capabilities of switchgear and standard auxiliary transformer impedances. These criteria are used to design a flexible and reliable auxiliary power system for a cyclic duty power generating station. The effect of mechanical equipment selection on the auxiliary power system design is discussed. An economic comparison of single voltage versus dual-voltage is made. A one-line diagram of the resulting proposed system is included.

Protective Devices Coordination via Computer Graphics

A method of coordinating short-circuit protective devices by the use of computer-generated graphics is described. Manufacturers' time-current characteristic (TCC) curves for protective devices are stored and used by the program in choosing the ratings and settings of devices to produce a fully coordinated system. Computer drafting techniques output both a one-line diagram and time-current characteristic curves on conventional 4? by 5 cycle log-log format.

Optimal Automatic Drawing of One-Line Diagrams

An optimal one-line diagram generator algorithm is presented. The corresponding cctputer program drives the output device to draw a one-line diagram which is optimal in the sense that for a given drawing area, the minimum distance between elements of the diagram is a maximum. The computer program needs little additional information about the topology of the network to that normally supplied to a load flow program. The problem is posed and solved as a longest path problem. Examples of results of this program coupled to a load flow program are presented.

Automatic Power System Network Topology Determination

The determination of power system network topology for off-line studies is a relatively simple problem since one-line diagrams inherently describe system configuration. In real time environments, system configuration is dynamic. Breakers may operate at any time producing some of the following effects: 1) circuits may or may not be disconnected, 2) substations may or may not separate possibly forming new nodes, thus varying the total number of nodes in a system, and 3) an interconnected system may split into several separated areas. Unless provisions are made to automatically incorporate in real time the effects of breaker operations on system topology, any calculation and decision based on a wrong configuration would be dangerous, especially when most needed: immediately after the occurrence of the abnormality ity which lead to breaker operations.

Principal Details of Design Drafting for Substations by Computer

The Bonneville Power Administration has been developing a system for producing substation design drawings by using automatic data processing methods. Although the system is not yet 100-percent operational on all phases of substation design, it is operational on 115-kV one-line diagrams, buslayouts for 500-kV breaker- and-a-half and ring-bus schemes, 115-kV customer's service stations, and some switchboard and relay panels. The basic programming structure has been established, and the system offers a practical and economical method of decreasing the man-hour requirements for substation design, where repetitive-type drawingsmust be produced for construction purposes. The project has been separated into six basic parts: 1) developing the basic logical structure, 2) reducing the graphical components to numerical data, 3) retrieving and assembling the necessary components for a specific drawing, 4) transforming the numerical data back into graphic form ( plotting), 5) generating a bill of material, 6) writing a material summary list. Ways of applying these parts to design drafting are discussed.

Procedure for Determining Maximum Short-Circuit Values in Electrical Distribution Systems

Written to be easily understood, this straightforward comprehensive procedure for short-circuit calculation presents familiar concepts in clear pictorial instructions supported with pertinent explanations. The System One-Line diagram and circuit data are used directly without conversion to unfamiliar abstract terms. Simple arithmetic produces readily evaluated results. Typical circuit data is offered for reference and an example demonstrates the complete procedure.

Substation One-Line Diagrams [includes discussion

Substation One-Line Diagrams [includes discussion

Standards: Graphical symbols for electric power and interior wiring

A report on a proposed American Standard for Graphical Symbols for Electric Power and Interior Wiring developed by a subcommittee of the Sectional Committee on Scientific and Engineering Symbols and Abbreviations was received at the December 13, 1929 meeting of the A. I. E. E. Standards Committee and was ordered printed in report form for distribution for purposes of criticism and suggestion. This report comprises graphical symbols used for one-line and complete diagrams of electric power apparatus, instruments and relays, system-connection diagrams, and interior wiring diagrams. The symbols are limited to apparatus usually met with in electrical power engineering, such as major electrical equipment in power houses, substations, and transmission and distribution systems and to system and building wiring diagrams. They are not intended to cover communication, railway or other allied branches of electrical engineering. Basic symbols seem to have widespread use and application, and only such symbols are given. This report will shortly be available in pamphlet form and copies may be had without charge by writing H. E. Farrer, Secretary, A. I. E. E. Standards Committee, 33 West 39th Street, New York, N. Y.