Unlike most other digital simulators that generate test waveforms for specific system configurations, playback previously recorded fault waveforms, or randomly generate artificial waveforms, the digital simulator presented in this paper generates the worst case waveforms for specified bounds on noise components present in the relay input signals. As a result, the performance limits of a computer relay can be determined, for specified bounds on its noise components, by performing a single test only. The parameters that define the worst case waveforms; are obtained by utilizing a modified univariate search algorithm. The PC-based simulator was implemented using a general-purpose multifunction card and a graphical programming package called Visual Designer. It did not require any text-based programming for tasks such as interfacing, digital-to-analog conversion, and outputting the discrete analog values of the generated waveform under hardware control. For demonstrating the operation of the digital simulator, a computer relay was also developed in the laboratory and its performance limits were determined.

A Digital Simulator for Determining the Performance Limits of Computer Relays

Implementation of a real time simulator for protective relay testing

Applications intended for simulation allow modeling and analysis much more often lately and they become indispensable for the development of any electrical and electronic system. The considerable reduction of time and costs of research and can be fixed if the method of simulating a power line can be done before designing the system, thus offering the possibility to avoid major errors that may affect the actual implementation of a system. This paper aims to picture that a simulation model can establish a very precise solution for different categories of researchers that develop various systems through designing the power lines for low-frequency.

Simulation model for designing the power lines for low-frequency

Traditional fighter electrical boxes detection system can not be efficient and accurate implementation in detecting electrical boxes, in order to achieve accurate detection of the electrical box, this paper had designed a detection device consists of upper machine and lower machine system. The system is based on the C8051F120 single chip microcomputer as the core. It is controlled by a machine on and off of the FPGA to drive the relay array to detect the safety status of electric box, through the communication between upper machine and lower machine to display the measurement results. The integrated test system can detect various fighter electrical control boxes, which overcomes the shortcoming of a test equipment in the past can only test a class of products, improves test accuracy and efficiency.

Development of Detecting System of Fighter Electrical Boxes

ISSN 0895-0156/02/$17.00©2002 IEEE To what extent is the use of transient tests prevalent in the policy of utilities: Acceptance tests Incidence analysis New modular relay definitions Optimal settings Corrective maintenance Relay selection? The main incentive of our research was to tackle the development of diverse tools that, in conjunction, made it possible to establish conclusions to answer this question.

Simulation and transient testing of numerical relays

With the appearance on the market of electronic test equipment that is controlled by software from personal computers, automation of classical test methods has been achieved and new methods have been developed. For engineers and technicians in charge of performing integrity and application tests, steady-state and dynamic tests can provide helpful information used in design, commissioning and preventive and corrective maintenance. These test methods result in savings of time and the cost involved in these tasks. Since 1990, the Spanish electric utility, Iberdrola, and the Electrical Department of the University of the Basque Country have been developing tools to: automate protective relay testing; analyze the location and characteristics of faults in the power network on the basis of oscillographic records; and simulate real or hypothetical fault conditions on a protective relay in order to monitor its behavior. Two automatic relay testing systems and experience of their use are introduced in this article. Particular testing protocols of different relays are incorporated and all useful features available to increase the automation grade are considered. Both systems minimize power system protection relay maintenance times and costs and improve the quality and reliability of relay management.

J.M. Gallastegui

Papers

Optimized relay testing systems