The first part of this work gives a broad introduction on the origins of ZnO bismuthbased
v aristor materials. The electrical properties of ZnO varistors follow, giving a detailed
and up to date review of all the models published with an attempt to explain their complex
conduction mechanisms. Stresses found in HV networks are also reviewed in detail, their
knowledge being necessary to link the de gradation and fail ure mechanisms of ZnO
varistors which are explained at depth. The manufacture of ZnO varistors on a laboratory
scale is also presented: disc type as well as thick-film type varistors were manufactured and
tested during this inv estigation. The parameters influencing the microstructure and
electrical characteristics of varistors during sintering were reviewed. Testing sequences
used by manufacturers as well as surge arrester testing standards were also assessed to
derive tests for the laboratory produced samples.
Date of Award | Nov 1995 |
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Original language | English |
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Awarding Institution | |
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The Effects of Multi-Current Impulses on the Low
Current Bulk Distribution In Varistor Materials, Under
Continuous AC Operation
Perrot, F. (Author). Nov 1995
Student thesis: Doctoral Thesis