Dielectric measurement in a wind farm - Summary

After relatively little time being installed, a significant number of tower transformers have suffered failures. Initially these faults seemed to have no justification apart of a defect of production or design of the transformers, as for example, the current flow was almost always less than nominal.

Measurement campaign shows an enormous amount of different types of transients, starting from intermittent ground faults to switching overvoltages, with the constant emergence of voltage notch. Analyzing the transformers Technical Specification, it was verified that there were no description of the special conditions of operation which were subjected of the transformers!

Description