This text/reference presents a comprehensive, up-to-date account of computer relaying in power systems, based in part on the author's extensive experience in the field. Provides background material on current relaying practices, and covers the mathematical foundations for relaying algorithms. Each chapter contains helpful illustrations, examples, and problems.

Computer Relaying for Power Systems

The authors present a new methodology based upon the principles of optimization theory, to treat the problem of optimal coordination of directional overcurrent relays in interconnected power systems. With the application of the proposed technique, this coordination problem is stated as a parameter optimization problem, which in general, is of a large dimension, especially when many different system configurations and perturbations are to be considered. Several optimization procedures, including direct methods and decomposition techniques, for solving this large scale coordination problem are described, and results of optimally coordinating directional overcurrent relays in power systems with up to 30 buses are presented. >

Optimal coordination of directional overcurrent relays in interconnected power systems

This paper presents a new algorithm suitable for calculating impedances from digitized voltages and currents sampled at a relay location. Each input is assumed to be composed of a decaying d.c. component and components of the fundamental and harmonic frequencies. Parameters of a digital filter determined by using the least error squares approach are then used to compute the real and imaginary components of the voltage and current phasors. Impedances as seen from a relay location are then calculated. The proposed algorithm was tested using the fault data recorded at the Regina South switching station of the Saskatchewan Power Corporation; some of the test results are included.

A New Algorithm for Digital Impedance Relays

A fundamental basis has been developed for the use of a time-shared stored-program digital computer to perform many of the electrical power-system protective-relay functions in a substation. Logic operations are given to detect a fault, locate it, and initiate the opening of the appropriate circuit breakers, whether the fault is in the station or on lines radiating from the station.

https://digitalcommons.njit.edu/cgi/viewcontent.cgi?article=2601&context=theses

Fault Protection with a Digital Computer

The use of digital techniques to adapt transmission system protection and control to real-time power system changes is investigated. The discussion covers transmission system protection philosophy, transmission line protection, relay settings, transformer protection, and automatic reclosing. The tradeoff between dependability and security is examined, as well as the various conflicting criteria embodied in transmission line protection. Adaptive strategies that minimize the compromises required and thereby optimize system performance are presented. >

Adaptive transmission system relaying

Digital Computer Protective Device Co-ordination Program I-General Program Description

An experimental general-purpose process-control digital computer system provides high-speed phase-and ground-distance fault protection of one 230 kV transmission line. The stored program performs all of the relaying functions using the output of an analog-to- digital converter which reads the instantaneous value of the power- system currents and voltages. Model line tests described in a companion paper (II -Test Results) form the basis for preliminary performance evaluation. An automatic oscillograph and diagnostic programs will allow a study of field performance.

High-Speed Distance Relaying Using a Digital Computer I - System Description

An experimental general-purpose process-control digital- computer system described in a companion paper (I-System Description) provides high-speed phase-and ground-distance fault protection of one 230 kV transmission line The stored program performs all of the relaying functions using the output of an analog-to- digital converter which reads the instantaneous value of the power- system currents and voltages Model line tests described here form the basis for preliminary performance evaluation An automatic oscillograph and diagnostic programs will allow a study of field performance

High-Speed Distance Relaying Using a Digital Computer II-Test Results

A novel basis has been developed for designing distance relays that will detect ground (earth) faults in a preset zone of transmission lines. The fundamental basis is described, and the relay performance is analyzed mathematically over a wide range of power-system conditions to show its constancy of reach and proper sense of direction. A relay designed on this basis can be zone-packaged and is inherently directional.

G. D. Rockefeller

Papers

Fault Protection with a Digital Computer

Digital Computer Protective Device Co-ordination Program I-General Program Description

High-Speed Distance Relaying Using a Digital Computer I - System Description

High-Speed Distance Relaying Using a Digital Computer II-Test Results

Zone-Packaged Ground Distance Relay: I - Principles of Operation