The next step in interrupting capacity — 5,000,000 kva

Serious consideration is being given to large power-system interconnections which could develop short circuits at certain locations in excess of 3,500,000 kva. High-voltage oil-circuit-breaker capabilities for such heavy duty are reviewed in this paper, the fundamental design requirements outlined, and results of high-power laboratory tests presented which demonstrate that interrupting capacity ratings as high as 5,000,000 kva are feasible. Laboratory test methods for demonstrating these extremely high arc rupturing ratings are evaluated. The importance of verifying high-speed reclosing performance with high-power tests is emphasised, and on the basis of data already obtained, standard reclosing time intervals considerably less than 20 cycles are foreseen.