ANALYSIS OF THE SWITCHING IMPULSE STRENGTH OF PHASE-TO-PHASE AIR GAPS.

This paper presents the results of an analytical and physical study of phase-to-phase strength based on experiments carried out at Renardieres. The flashover voltage was determined by the Up and Down method, both components varying simultaneously. Each sequence included 50 significant shots. Charging voltage, crest voltage, waveshape, time-to-breakdown, climatic parameters and static pictures of the discharge were recorded for every shot. In the most significant cases, physical measurements were carried out with an image converter camera and photomultipliers. The relative importance of the main parameters comes from their systematic analysis and could influence the testing procedure. Basic values are given for the most important configurations for design purposes.