Effect of point cathode and point anode on conduction and burst current in an inhomogeneous field for inservice transformer oil

This paper presents a study on the effect of point cathode and point anode on conduction and burst currents in transformer oil under high field. It has been found that the current in point cathode is higher than in point anode. Field emission satisfies the Fowler-Nordheim relationship in both cases within a range of applied voltage, and above which space charge contribution becomes dominant. The rate of current decrease in point anode is faster than point cathode. The amplitude of UDI-Burst in point cathode is larger than point anode. The total number of burst per minute is larger for point anode than the point cathode. The condition mechanism is discussed and the role of liquid/metal interface is emphasized.