An Analysis the Effect of Compound Electrode Materials to Transient Recovery Voltage and Chopping Current in Low-Current Vacuum Arc

The purpose of this research was to analyses and compare the instability of a contact surface between copper and nickel as an alloy cathode in vacuum, the different ratio of copper and nickel were conducted at 1%, 4% and 6% by using the cathode spot model which is recognized as the collisionless space charge sheath connected with singly ionized collisional plasma. It was found that the minimum stable arc current is highly dependent on the thermal conductivity of the cathode material due to amount of percent nickel. The chopping current is proportional to the level of minimum stable arc current. As results, the smaller recovery voltage which is induced by chopping current. This is a very important result for the development of cathode materials for low-surge vacuum interrupters. The results obtained by this study clearly demonstrate the physical mechanism of current instability occurrence, the level of chopping current and the recovery voltage in power system