IN THIS PAPER POLARIZATION AND DEPOLARIZATION CURRENTS MEASUREMENT TEST METHOD IS DESCRIBED. THEN IN ORDER TO ASSESS THE CONDITION OF STATOR WINDING INSULATION OF RAY POWER PLANT GENERATOR, THE CHARGE AND DISCHARGE CURRENTS FLOWING THROUGH MACHINE GROUND WALL WINDING INSULATION ARE MEASURED AND ANALYSED. RESULTS FROM THIS TEST ARE APPROVED BY PARTIAL DISCHARGE ANALYSIS OF INSULATION.