New method for prediction of insulating liquid AC breakdown

Paper compares three most widely used methods in insulating liquid breakdown prediction: cumulative stress method, stressed electrode area and stressed liquid volume. Breakdowns were measured on Midel 7131 on OTS100AF oil tester with two different electrodes at three gap distances. Prediction capabilities of three methods were tested with respect to results of conducted measurements and research done by other authors. The utilization of these methods is enhanced by application of numerical calculation of electric field. It is shown how these methods are interrelated and a proposal for their unification is given. Unification model is confirmed on measurements conducted in this and other research papers.