Modeling relays for power system protection studies

Numerical relays are the result of the application of microprocessor technology in relay industry. Numerical relays have the ability to communicate with its peers, are economical and are easy to operate, adjust and repair. Modeling of digital and numerical relays is important to adjust and settle protection equipment in electrical facilities and to train protection personnel. Designing of numerical relays is employed to produce new prototypes and protection algorithms. Computer models of numerical relays for the study of protection systems are greatly enhanced when working along with an electromagnetic transient program (emtp). A literature survey has revealed that previous modeling techniques presented a lack of automation in the generation of relay models, or show high complexity in linking the numerical relay models with the power system modeled in the emtp. This thesis describes a new approach of modeling and designing of numerical relays. The proposed methodology employs a Visual C++-based program (PLSA) to obtain from the user the specifications of the relay to be designed, and to process this information to generate the FORTRAN code that represents the functional blocks of the relay. This generated code is incorporated in a PSCAD/EMTDC case using a resource called component, which facilitates the creation of user-custom models in PSCAD/EMTDC. Convenient electrical and logical signals are connected to the inputs and outputs of the PSCAD/EMTDC component. Further additions of digital relay models into the PSCAD/EMTDC case constitute the protection system model. The thesis describes a procedure for designing distance and differential relay models, but the methodology may be extended to design models of other relay elements. A number of protection system studies were performed with the structure created with the proposed methodology. Adjustment of distance and differential relays were studied. Relay performance under CT saturation and the effects of the removal of anti-aliasing analog filter were investigated. Local and remote backup distance protection of transmission lines was simulated. The adjustment of differential protection of power transformer to overcome the effects of inrush current was performed. Power transformer differential protection responses to internal and external faults were considered. Additionally, a set of tests were performed to investigate the consistency of the relay models generated with the proposed methodology. The results showed that the numerical relay models respond satisfactorily according with the expected results of the tests

A Prototype of Web-Based Simulation Environment (WEBSIM)

Computer simulation is the discipline of designing a model of an actual or theoretical physical system, executing the model on a computer, and analysing the execution output. Among the popular simulation tools are Mil3 Opnet, Mathworks MATLAB and even self-developed simulation program (using language such as Pascal, Fortran and C/C++). However, these simulation tools have limitations such as platform dependent, expensive cost, maintenance difficulties and limited in reusability. One of the methods to overcome this limitation is by implementing web-based simulation. Web-based simulation allows simulation to be carried out over the Internet using a standard web browser. The usage of web browsers make the Internet a very user-friendly environment by integrating all related resources into a single tool that eliminates the steep learning curve for novice simulation users. In this thesis, we present the web-based simulation environment project (Websim). Websim uploads a simulation program (developed using C/C++) in binary format, generates a web-interface for the program and allows users to access the simulation program y 1<1 the Internet. The results generated from the simulation program would be translated into an image file. Finally, the Image file is embedded into an HTML file, and returned to Websim users. Websim is mainly developed using the combination of CGI and Javascript technologies. The server-side CGI scripts, written in Perl process the various requests from users, while the chent-side Javascript is used to perform user inputs validations. Thus, lessen the workload of the server and tighten the security. Websim is able to receive the simulation program m executable format and provide a web interface for it. This gives the flexibility and convenience of using the programming language of choice for the simulation modeller, and to integrate it with the web. Besides that, Websim also allows the storage of simulation program on a web server, thus could act as an online store for simulation programs. This permits the sharing of simulation program over the Internet, to an exclusive user groups or to the general public. Finally, Websim could act as a teaching tool in school and universities, especially for courses involving modelling and simulation. It allows teaching and learning to be done through the Internet, hence could assist students in having a better understanding on certain topics or concepts

Organisation of the EUROPLEXUS Mirror Site (MS-Windows) at JRC Ispra, Seventh Edition

This document describes the organisation of the “mirror site” for the development of the EUROPLEXUS computer code at the Joint Research Centre (JRC) of the European Commission (EC) at Ispra.JRC.G.5-European laboratory for structural assessmen

NASA Tech Briefs, February 1994

Topics covered include: Test and Measurement; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences; Books and Report

A Windows program for airfoil design using B-splines

The objective of this thesis has been threefold. First, the formulation of splines has been studied and their development into a computer algorithm has been implemented. Splines represent a powerful concept in computer modeling and geometric representation, for, as parametric curves, they provide a compact way to store the information defining a curve or surface. B-splines have been exclusively used in this thesis, although other types of splines exist. The second goal of this thesis was to learn and utilize C++ as a programming tool in the demonstration of B-spline techniques. C++ was chosen because it is object-oriented, and because it is the chosen language of the Microsoft Windows PC platform. Many languages are object-oriented, but C++ was chosen to make use of its libraries to build standard Windows interfaces and objects. The third piece of this thesis is an effort to explore the fundamentals of inter-language communications. Many old scientific codes are already written in older languages like FORTRAN, so it is advantageous to re-use those codes where possible. Digital Visual FORTRAN, a module of the Microsoft Visual Studio, has provided a powerful tool in their integration of multiple programming languages for Windows applications. Using Visual Studio, it is possible to re-use existing FORTRAN code and envelop it in a C interface using a dynamic link library (DLL) file. This thesis uses a C++ application for defining any typical airfoil using B-splines. The software package calls XFOIL, a code written in FORTRAN to evaluate the aerodynamic characteristics of those airfoils. Further, those characteristics have been compared to those of the original geometry to evaluate the interpolation process used by the splines

Origins of Analysis Methods in Energy Simulation Programs Used for High Performance Commercial Buildings

Current designs of high performance buildings utilize hourly building energy simulations of complex, interacting systems. Such simulations need to quantify the benefits of numerous features including: thermal mass, HVAC systems and, in some cases, special features such as active and passive solar systems, photovoltaic systems, and lighting and daylighting systems. Unfortunately, many high performance buildings today do not perform the way they were simulated. One potential reason for this discrepancy is that designers using the simulation programs do not understand the analysis methods that the programs are based on and therefore they may have unreasonable expectations about the system performance or use. The purpose of this study is to trace the origins of a variety of simulation programs and the analysis methods used in the programs to analyze high performance buildings in the United States. Such an analysis is important to better understand the capabilities of the simulation programs so they can be used more accurately to simulate the performance of an intended design. The goal of this study is to help explain the origins of the analysis methods used in whole-building energy simulation, solar system analysis simulation or design, and lighting and daylighting analysis simulation programs. A comprehensive history diagram or genealogy chart, which resolves discrepancies between the diagrams of previous studies, has been provided to support the explanations for the above mentioned simulation programs

MIRMaid: An interface for a content based Music Information Retrieval test-bed

Music Information Retrieval (MlR) is the interdisciplinary science of retrieving information from music and includes influences from different areas, like music perception and cognition, music analysis, signal processing, music indexing and information retrieval [Futrelle & Downie, 2003]. To produce the most efficient MlR systems, test-beds are commonly used to test different combinations of parameters against each other. The purpose of this dissertation was to investigate the composition of algorithms for MlR systems by constructing an interface that could form part of a test-bed. It differs from other interfaces and frameworks that are used in MlR test-beds because it is focused on small scale test-beds. MIRMaid is an acronym for Music Information Retrieval Modular aid and is an interface that allows different content based retrieval tasks to be compared against each other to find optimal combinations of retrieval parameters for specialised problem domains. The dissertation describes the process of how the MIRMaid interface was developed, modified and refined. A big challenge was to design the user experiments in a way that considered potential users of the interface while using the test subjects I had at my disposal. I decided to use the simplest queries to highlight basic similarities between novice and potential expert users. The performance of the interface was judged by user ratings on a questionnaire. The interface performed reasonably well with expert users and novice users. Despite these results there were a few interesting observations that were returned from the user experiments related to the experiment design and the task explanations. Some suggestions are also provided for extending the interface to allow it to be used with other types of data. The possibility is also investigated for using the interface as a tool for simplifying the process of integrating modules from different sources

NASA Tech Briefs, October 2000

Topics include: special coverage sections on CAD, CAE, and PDM, and, Composites and Plastics, and sections on electronic components and systems, software, test and measurement, mechanics, manufacturing/fabrication, physical sciences, information sciences, book and reports, and special sections of Electronics Tech Briefs and Motion Control Tech Brief

A review on the integration of artificial intelligence into coastal modeling

Author name used in this publication: Kwokwing Chau2005-2006 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Development Of Alarm Monitoring And Analysis Tool

Alarm monitoring and analysis is one of the instrument engineer job scope. Alarm monitoring and analysis is very crucial to maintain the safety and performance of the plant. The objective of this project is to develop alarm analysis tool using the software and tools that are readily available such as Microsoft Excel