Experimental evaluation of current transformer performance under saturation

Abstract

Current transformers form an integral part of protective systems. Ideal Current Transformers (CTs) are expected to reproduce the primary current faithfully on the secondary side. Often, during fault conditions an important component of current is exponentially decaying DC offset current. Under such conditions the CT saturates, and hence it cannot reproduce the primary current faithfully. This paper deals with experimental methods for determining CT performance under saturation. A laboratory setup has been developed to observe CT response under steady state and fault conditions. Thus, it is now possible to experimentally evaluate the CT performance under fault conditions.