A survey of ELCID applied on insulation faults of stator cores

This Electromagnetic Core Imperfection Detection (ELCID) has been widely used on generators and large motors in detecting inter-laminar insulation failure in stator cores. Comparing to traditional detecting method, the requirements of ELCID are much more easier to obtain, so it is necessary to analyze the results of ELCID in engineering application. On the one hand, the validity of ELCID in detecting generator cores still needs to be analyzed, especially when inter-laminar insulation faults are buried in a stator core. Computer simulation based on finite element method is an effective way to predict the measuring results of ELCID, so in this paper, computer simulation is used to analyze the features of ELCID. On the other hand, core loss will more or less affect the ELCID detection results, so a field test has been made to analyze this. The simulation results indicate that ELCID has ability to make comparatively accurate judgment about severity of insulation damages on surface of generator stators, with the deepening of the positions of insulation faults, the accuracy of detection results get worse. Meanwhile, core loss will affects detection results of ELCID.