The paper presents a new approach to the calculation of transients on transmission lines with frequency-dependent parameters. Its purpose is to obtain significant computer-time savings by avoiding convolutions. This is achieved by approximating all line and ground distortions and also time variable characteristic admittances by exponential functions, i.e. solutions of linear differential equations. The method produces a simple Norton-type line equivalent which permits its incorporation into an existing system representation like the B.P.A. program for the calculation of transients. The program has been tested on systems of different degrees of complexity and proved to be superior, in terms of speed and accuracy, to other advanced methods.

Fast and accurate switching transient calculations on transmission lines with ground return using recursive convolutions

A new protective relay that solves many of the problems associated with the protection of EHV and future UHV systems is described. Based on a traveling wave approach the relay system operates at ultra high speed and can detect and determine the direction to a fault in a few milliseconds. The relay operating principle, design and application are presented as well as results from computer simulation studies and laboratory tests. The first relay system was installed in the USA in Bonneville Power Administration's 500 kV system and represents a substantial contribution to present efforts to shorten fault clearing times as a method to improve system stability and power transfer capability.

Ultra High Speed Relay for EHV/UHV Transmission Lines -- Development, Design and Application

Simulation programs for electromagnetic transients must provide models for lightning arresters, transformer saturation, circuit breakers and other nonlinear and time-varying effects. This paper describes techniques for keeping the solution time in networks with such elements as low as possible, by using the compensation method or network equivalents.

Nonlinear and Time-Varying Elements in Digital Simulation of Electromagnetic Transients

This paper describes an extension of Bergeron's Method of Characteristics that is applicable to the analysis of transmission lines with frequency dependent parameters. This method can be inserted in existing general purpose programs that use Bergeron's Method. The application to single phase and multiphase transposed lines is discussed with examples and the theory is developed for multiphase untransposed lines.

Propagation of Travelling Waves on Transmission Lines - Frequency Dependent Parameters

Resonant overvoltages in EHV transformers initiated by events on connected transmission lines have been experienced.

Resonant Overvoltages in EHV Transformers-Modeling and Application

A digital computer program for the calculation of switching and lightning surges on three-phase power systems is presented. It is designed for fast operation, statistical processing of results, and high versatility in network representation. Network elements can be symmetrical or asymmetrical, linear or nonlinear. Transmission lines can be transposed or nontransposed and may have frequency-dependent damping.

K. Lennart Carlsson

Papers

A Digital Computer Program for the Calculation of Switching and Lightning Surges on Power Systems