skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Investigation of feasibility of vacuum-arc fault-current limiting device. Final report

Technical Report ·
DOI:https://doi.org/10.2172/5196972· OSTI ID:5196972

The feasibility of a vacuum arc fault current limiter was investigated in this project. A magnetic field was used to interrupt or control the current flow in a vacuum arc device. The configuration of the device is such that electron current is forced to flow primarily radially outward from the end of a relatively small rod shaped cathode to a ring shaped anode. Control is achieved through the application of an axial magnetic field. Operation at current levels in the 5 to 10 kA range have been demonstrated for periods up to about 8 ms. The voltage of operation that has been demonstrated is less than required because of discharge paths that develop within the device in parallel with the desired path from the cathode to the anode. Significant progress was made in eliminating these discharge paths by using insulating shields between the anode and the cathode support structure. In the process of developing design criteria for vacuum arc FCL's, several other studies were performed. A brief study of fault current limiter commutation voltage requirements showed that the voltage appearing across a commutation device could be limited to a very reasonable value if the commutation current waveform was properly controlled. A study of magnetic flux concentration using the anode in a vacuum arc switch showed experimentally and theoretically that concentration times up to about one millisecond are practical with a copper anode. Another study dealt with an investigation of the phenomena occurring during the ignition of arcs on gold and on copper cathodes. For distribution circuit applications of fault current limiters, it appears feasible to limit the fault current and to absorb the energy associated with the fault current limiting process in a single vacuum arc device of the type that has been under investigation at SUNYAB. While considerable progress has been made improving the voltage and current rating of this device, the goals established at the outset were not achieved.

Research Organization:
State Univ. of New York, Buffalo (USA)
OSTI ID:
5196972
Report Number(s):
EPRI-EL-538
Country of Publication:
United States
Language:
English