Performance measurement and analysis of openable core current transformer

The openable core current transformer is widely used in the on-site measurement due to its convenience. However, the existence of air gap leads to the decrease of core magnetic performance, so it is rarely used in the field of precision measurement. Two kinds of high quality soft magnetic materials are selected to analyse the difference of key magnetic properties before and after core cutting, so as to promote the rational configuration of materials. Establish the mathematical model for the openable core current transformer and decompose the impact of ratio error and phase displacement. Employ permalloy as the measuring core; produce a prototype of openable core current transformer; and the fractional turn error compensation is adopted. The results show that the ratio error and phase displacement of the prototype satisfy the requirement of 0.1 S class error limit, which may provide the reference for the development of high precision openable core current transformer.