Effect of Impurity Bridges on Breakdown Strength of PFAE under Lightning Impulse Stress

This research investigates the effect of cellulose bridging formation on the breakdown strength of Palm Fatty Acid Easter (PFAE) under Standard Lightning Impulse Voltage (SLIV). An impulse generator up to 140kV (max) was used as a source of SLIV and it is applied according to the IEC60897 standard for the breakdown voltage test. The cylindrical test cell with sphere-sphere electrodes gap was utilized in this experiment. The application of DC source to the test cell generates quasi-uniform field between the electrodes gap which form cellulose bridging. The breakdown strength of PFAE was analyzed using a Weibull Cumulative Breakdown Probability. The statically analysis was always compared with the Clean Oil as a reference. Based on the experimental results, the cellulosic particle reduced nearly 4.5% breakdown strength of contaminated PFAE oil. The particle influence on electrical field strength also becomes more prominent and further breakdown more than 24.5% when the bridging is formed. As a conclusion, the present of particles and its bridge structures were headed to the detrimental effect of liquids strength by reduced the field strength of PFAE up to 29% under the lightning impulse stress.