The impulse characteristics of oil gaps from the standpoint of insulation coordination

Electrical Engineering

McCann, Gilbert Donald ; Unknown, Unknown

University:California Institute of Technology

Department:Engineering and Applied Science

关键词: Electrical Engineering;   

Others  :  https://thesis.library.caltech.edu/1768/1/McCann_gd_1939.pdf

美国|英语

来源: Caltech THESIS

【 摘 要 】

The development and use of high voltage surge generating equipment are described in this thesis.

Impulse equipment capable of producing and recording standard test surges up to 2,000,000 volts for both research and commercial testing have been developed.

The present status of insulation coordination shows the need for more data on the impulse characteristics of large oil gaps.

A new type of oil test tank has been constructed which permits less gap field distortion and better conditioning of oil and electrodes than was formerly possible for large gaps at high voltage.

The impulse characteristics of oil gaps having spacings ranging from one-half to eight inches formed by circular brass rods with spherical ends from one-fourth to two inches in diameter have been determined.

It is found that such gaps have impulse strengths which are greatly affected by slight changes in conditions of both the oil and electrode surfaces.

Their impulse values are much higher than their 60-cycle strengths and are functions of the wave shape of the surge.

The most probable type of breakdown mechanism was found to be the thermal electric breakdown initiated by impurities in the oil.