In 2008/09 Nexans SuperConductors GmbH made the step from R&D activities to the production of the first non-publicly funded fault-current limiter units. In close cooperation with two customers, Applied Superconductor Limited (ASL, UK) and Vattenfall (Germany), Nexans was able to design, produce and deliver two resistive superconducting limiter devices. Both devices are designed for the medium voltage grid and were tested at the high voltage and high power lab IPH in Berlin. The superconducting components of both limiters, coils of bulk MCP BSCCO-2212, have been designed and produced by Nexans.

No abstract

No abstract

No abstract

There have been several cases of dielectric faults and failures in power transformers identified internationally that have been associated with system operation. This paper discusses UK examples and concludes the evidence indicates internal overvoltages arising from part winding resonance. These resonances are initiated by remote energisation, either intentionally or by the action of automatic re-energisation schemes after line trips. Some designs are more prone to the problem, and it is here that diagnostics such as sweep frequency response analysis may give some indication as to designs more at risk.