Patent ID: 8411400
Filing Date: 2013-04-02
Classification: G05F,H02H

Abstract:
1. An apparatus for mitigating in less than the time for one cycle of a predetermined operating frequency of an AC network a short term dynamic overvoltage on said AC network, said apparatus comprising: a distribution and power transformer having a primary connected to a high voltage bus and a secondary directly connected to a switching device that can switch from a nonconductive mode to a conductive mode within a time that is less than the time for one cycle of said network predetermined operating frequency; and a system connected to said switching device, said system comprising: one or more detectors for detecting the occurrence of a condition known to cause a dynamic overvoltage on said AC network and the occurrence of a dynamic overvoltage on said AC network; and a control system connected to said switching device, said control system in response to said one or more detectors detecting at the same time both said occurrence of a condition known to cause a dynamic overvoltage on said AC network and the occurrence of a dynamic overvoltage on said AC network causing said switching device to change in less than said time for one cycle of said predetermined operating frequency from said nonconductive mode to said conductive mode to thereby short circuit said transformer secondary.