On the size effect in the testing of breakdown voltage of PE power cables

The results presented confirm the effect known from other works e.g. ⁴, that the electric strength of solid insulation decreases with the increase of its linear dimensions /size effect/. The application of a point electrode forced a breakdown to occur in a predetermined area. So the decrease of strength could not be related with the increase of the number of weak points. This is also confirmed by the experiment with the short response time capacitor, coupled in parallel, which caused the decrease of breakdown voltage. The sample dimensions remained unchanged, whereas the energy accumulated in the direct vicinity of breakdown area is different.