Switching Impulse Strength of Compacted Transmission Line Flat and Delta Configurations

Five transmission line phase configurations suitable for phase compaction were simulated and tested in a large portal testing tower to establish phase-to-phase and phase-to-tower switching surge insulation requirements for 765 kV systems. Using these results and other data available from the literature, clearances for 345, 500, and 1100 kV systems also were developed.