A new controlled fault limiting algorithm for vacuum fault current limiter based on fault current zero-crossing prediction algorithm

A new controlled fault current limiting (CFL) technology based on series vacuum switch was proposed to decrease the overvoltage and arc energy in current converting process. Compared with the directly fault current limiting (DFL), the response time of the CFL limiter, which is based on an optimum fault current zero-crossing prediction algorithm, was defined and analyzed. The arcing time, arcing current integral and fault current converting time under CFL and DFL were defined and simulated. The results showed that the arcing time was reduced significantly; the contact burning was weakened, but the current converting time was extended sometimes under CFL. So, the proposed CFL algorithm can reduce the transient effect and improve the success rate of current converting.