The authors review Australian experience with a system of overvoltage protection for distribution transformers, first implemented in 1965-6. The major reduction achieved in transformer failure rates is attributed to the relocation of HV arresters close to the terminals, and to the fitting of LV arresters. Previously unpublished data from more than 12 years of field experience supports this attribution, and confirms Australian and subsequent American and Norwegian laboratory studies. During the field programme, several thousands of arresters were recovered from service, and the results of post-recovery tests, and of examinations of dismantled components, were compared with their service history.
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