Evaluation of different types of steel under high loading rates for short circuit applications

Abstract

This paper draws from independent experimental results pertaining to the properties of steel loaded at high strain rates, similar to those found in power transformer short-circuits. The types of steel that were tested are common non-alloy structural steel and high strength structural steel. The experiments showed that the most common types of structural steel, when loaded at high rates, are capable of absorbing considerably more energy than in quasi-static conditions. On the other hand, the high strength structural types of steel that were tested showed no improvement in their energy absorbing characteristics at high strain rates. The paper provides some examples to show how the experimental results may be incorporated in the design of steel components for short circuit safety. The last part is focused on the plastic deformation of steel and assesses its influence on the impedance variation of the power transformer following a short circuit.