Behavior of transformer insulation under short-time overvoltage
This paper reports on a series of tests made on transformer insulation samples with automatically applied short-time a.c. overvoltages above the corona inception level to determine the conditions under which damaging corona occurs. Modified dielectric tests for power transformers are discussed.
Switching Surge Response of Transformer Insulation Designed on the Basis of Power Frequency PD Inception Volt-Time Curves
The paper presents the results of power-frequency and switching-surge tests performed on transformer insulation models.
Gas Evolution From Transformer Oils Under High-Voltage Stress
Some insulating oils when subjected to high-voltage stress undergo chemical changes that result in the formation of various gases. Since there are different insulating oils available to users that are made by various finishing techniques resulting in oils of significantly varied composition, a study of a range of these materials was made to show if they produced different amounts or types of gases. The evolution of gases from oils in atmospheres of hydrogen and nitrogen were studied when the stressing voltage and temperature were varied over reasonable ranges.