Predicting the optimum routine test interval for protective relays

Abstract

This paper discusses the goals of routine maintenance testing for protective relays. The paper advances a Markov probability model that predicts the optimum test interval for protective relays with and without self-testing capabilities. The model uses known system transition rates and relay failure rates. The probability model shows that the optimum test interval for a relay with self-tests is quite long.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>