Interchangeability of measuring coils in Rogowski current transducers is the requirement of commercial production. This paper presents the concept of interchangeability of measuring coils. The operating principles of measuring coils are reviewed. According to the magnetic flux density profiles along measuring coils and the coil equivalent circuit

the influences of dimensions and electromagnetic parameters of measuring coils on interchangeability are analyzed in detail. The outlines and methods to improve the interchangeability are proposed.