Abstract: The measuring fundamentals of the shifting potential test for the stator bar terminal of the turbogenerator was introduced, the measuring method and matters needing attention were introduced too. The tests have been done for two 200MW water internal cooling generators. Many hidden dangers existed in the terminal insulation of the generators were found, and relevant measures were adopted; the safety and stable operation of the units were ensured.

Key words: turbo-generator, shifting potential, terminal insulation, manual-wrapped insulator