Accelerated-Frequency Hydrogen-Atmosphere Voltage-Endurance Testing of Micaceous Insulation Systems

Voltage-endurance testing of high-voltage micaceous insulation systems has traditionally been performed at normal power frequency. The test atmosphere has been air. The completion of tests in practical time periods has required the use of high dielectric stresses. Two series of voltage-endurance tests were conducted on micaceous insulation systems. These tests were designed to determine the effect on insulation life of accelerated frequency and of hydrogen atmosphere. The frequency of the test voltage was 412 Hz. From these tests two conclusions are drawn for voltage stress below 150 V/mil: 1) the voltage-endurance life-test rate was accelerated linearly with the increase of the frequency of the test voltage, and 2) the hydrogen atmosphere extended voltage-endurance life by a factor of at least 4.