Insulating and Switching Media in Medium Voltage Distribution and Medium Voltage Motor Control

(Eaton Corporation, 2008) An evaluation of insulation and switching media in medium voltage (1 – 52 kV) applications is presented in this paper. Special attention is given to motor switching and to distribution of electricity. The various insulating and/or switching media like oil, epoxy resin, air, SF6 and vacuum are discussed along with their pros and cons in different applications.
Key words are associated to the prevention of the various overvoltages that might occur in industrial networks and their relation to the switching media. The basic phenomena, such as current chopping and restrikes, are reviewed and the harm that overvoltages can cause either by amplitude or rising time to the equipment. Besides the overvoltage aspects, the operation and maintenance aspects related to different insulating and switching media are surveyed and discussed. 
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