Assess the impact of the steep-front, short duration impulse on electric power system insulation: Phase 1, Final report

Concern has been expressed with respect to the dielectric integrity of today's power systems and power system components when subjected to steep front, short duration (SFSD) impulse. Impulses of this type are characterized by voltage rise times of 10 to 250 ns and durations to several ..mu..s. A review of the literature on SFSD impulse and its associated impact on the insulating systems used in power system apparatus was completed. SFSD impulse was found to be the result of several sources including both lightning and nuclear electromagnetic pulse (EMP) and may contribute to the so called anomalous behavior or failure of electrical apparatus. The insulation systems used in power system apparatus were ranked with respect to vulnerability to SFSD impulse. The power insulating systems believes to be at greatest risk are the porcelain/air structural insulation (line insulation) and the paper/oil/enamel systems (transformers). Events reported in the open literature as anomalous behavior or failure were cataloged and characterized. The bibliography is available as a separate report.