Research on linearity measurement method of impulse current measuring devices

Linearity is a key technical parameter of the impulse current converting devices which directly affects the measurement accuracy of the impulse current measuring system. The factors affecting the linearity of different types of impulse current converting devices have been studied. Standard devices for on-site calibration of the linearity of industrial-grade impulse current measuring devices have been developed, including multilayer PCB-type Rogowski coils and magnetic field sensors based on Archimedes coil modules. Different linearity evaluation methods such as temperature rise calculation method, equivalent energy method, compared with Rogowski coil, compared with magnetic field sensor have been studied and tested. For a 100kA shunt-based impulse current measuring system, the test methods, applicable conditions and measurement levels of different methods are compared. The test results show that the linearity measurement results of several methods differ by about 0.7%, and it is more practical to compare with the linearity standard device under the condition of not knowing the material characteristics of the shunt.