Development of a numerical comparator for protective relaying. I

This paper derives, and explains the use of new numerical comparator concepts. These numerical techniques are new approaches to time domain based relaying algorithms. The initial treatment of the paper concentrates on the generalized idea of a phase comparator and the cylinder unit in particular. The focus in the cylinder unit is to extrapolate for digital relaying purposes, the benefits and characteristics of the well known and widely used relaying unit. The application of the numerical comparator techniques are illustrated with practical units. Distance, directional and over-threshold units illustrate the procedure to obtain protective relaying units using the numerical comparator concepts