| 摘要 |
A reference point of an electrical system is connected to earth 24 through a series fault current limiter 22 comprising an element 26 that is superconducting during normal use and is rendered non-superconducting by the occurrence of excessive fault current. Super conducting element 26 may remain superconducting while conducting normal earth leakage current, and may be a material which quenches when conducting current that exceeds its critical current. A shunt 30 may be connected in parallel with the superconductor 26 to reduce the heat dissipated by the superconductor 26 to cryogenic arrangements 32 when in fault conditions and assist recovery from a quenched condition. Shunt 30 may be resistive, and may have lower impedance than that of superconductor 26. Monitor 34 may detect a voltage difference across superconducting element 26 to indicate the onset of fault conditions by a signal 36. The reference point (fig 1, 20) may be a neutral point and the electrical system may comprise a plurality of aforesaid connections. |
