Limitation of Fault Current and Burden of Superconducting Element Applied to Neutral Line of the Transformer

The consumption of electrical energy has been increased since industrial revolution and still increasing so far. As the consumption of electricity increases, the problem of the failure of electric device and degrading of electric reliability by over current from the related fault happened. Therefore, the research of electrical device using high-temperature superconducting element is going on now and superconducting fault current limiter (SFCL) was applied on the neutral line of common transformer. As the applied voltage increases, the characteristics of the electrical power burden of SFCLs were studied. In case of fault in the power system, superconducting element restricted the fault current by normal conductivity element connected in third winding of a transformer. As a result of the test, it was confirmed that the conduction element limited initial fault current promptly as the voltage increases. After this, the conduction element took the power burden of fault current by changing the way of current and the limit rate became high as well. Also, it was confirmed that the power burden of conduction element was reduced due to no change of limit rate of fault current. By adapting of the SFCL to neutral line of a transformer and of normal conduction element to power system in the third winding, the use of current protection facility became available without increase and change of the capacity. Accordingly, the current limiter which was applied on the neutral line of a transformer was considered to have effects of cost saving, preventing mechanical failure and expansion of fault.