Controlled Fast Vacuum Breaking of an AC Short-Circuit Current in a Short-arcing Time

Abstract

A quick elimination of short-circuit faults in a short time can significantly promote the transient stability of an AC power grid. This paper proposes controlled fast vacuum breaking (CFVB) of a short-circuit current within a short-arcing time. The CFVB technology performs the following: determining a lower-limit opening speed of 3.5 m/s for a 40.5 kV fast vacuum circuit breaker (FVCB), quickly predicting the fault current-zero within 4.0 ± 0.4 ms to command the FVCB to open at a selected current phase-angle, and optimizing an electromagnetic repulsion actuator with an opening time of 2.5 ± 0.05 ms to achieve an accurate opening operation. The CFVB technology was deployed in a prototype of single-phase multiple-break 363 kV FVCB to validate its feasibility. The validation involved test duties of T100s(b) and T100a following standards IEC 62271-100 2017 and GB/T 1984-2014. Test results demonstrated that by adopting the CFVB technology, the 363 kV FVCB can successfully interrupt a fault current of 80 kA rms within the first half-wave fault current with a short-arcing time of 2.5 ms. Further application of the CFVB technology could help promote the transient stability of power distribution and transmission systems.