N/sub 2//SF/sub 6/ breakdown in concentric cylinders: consolidation of data

Electricite de France (EDF) is contemplating 420 kV compressed gas insulated cables (CGIC) as much as tens of kilometers long and environmentally acceptable. A literature review, measurements, and calculations were made for nitrogen alone or with minimum SF/sub 6/ for insulation of concentric cylinders. Data from different sources needed to be consolidated. It was found best to account for (at least approximately) both the similarity law for cylinders and the area effect, in order to visualize data from several sources together on one graph per mixture.