The main purpose of the work presented here is to evaluate different methods for quality control of polymer- ic insulated HVDC cables. The insight gained can be used to evaluate proposed test methods for quality assurance of long lengths of polymer insulated power cables. Laboratory experiments were performed using both Rogowski shaped test objects and model cables, insulated with XLPE containing imbedded spherically shaped particles. Tests were per- formed by stressing the test object with AC （50 Hz）, VLF （0.1 Hz） and DC voltages and measuring time to break- down at the different voltages. The slope of the voltage-time curve for 0. land 50 Hz were found to be parallel show- ing higher breakdown strength for 0.1 Hz than 50 Hz. The number of periods to breakdown is somewhat higher for 0.1 Hz than for 50 Hz. The breakdown strength for DC was~ much higher than for both AC 50 Hz and 0.1 Hz. The results indicate that the VLF test voltage needs to be 2 to 3 times higher than at 50 Hz power frequency in order to eliminate the same defects within a comparable time.